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Werner MH, Olanow CW, McGarry A, Meyer C, Kruger S, Klint C, Pellecchia J, Walaker S, Ereshefsky L, Blob L, Hassman H, Rodriguez C, Samara E, Safirstein B, Ellenbogen A. A Phase I, Randomized, SAD, MAD, and PK Study of Risvodetinib in Older Adults and Parkinson's Disease. J Parkinsons Dis 2024; 14:325-334. [PMID: 38251063 DOI: 10.3233/jpd-230319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Background Pre-clinical studies suggest that c-Abl activation may play an important role in the etiology of Parkinson's disease, making c-Abl an important target to evaluate for potential disease-modification. Objective To assess safety, tolerability, and pharmacokinetics of the c-Abl inhibitor risvodetinib (IkT-148009) in healthy subjects and participants with Parkinson's disease. Methods Part 1 (single ascending dose (SAD)) and Part 2 (7-day multiple ascending dose (MAD)) studies were in healthy volunteers. Participants were randomized 3 : 1 across 9 SAD doses and 3 MAD doses of risvodetinib (IkT-148009) or placebo. Part 3 was a MAD study conducted at two doses in 14 participants with mild-to-moderate PD (MAD-PD). Primary outcome measures were safety, tolerability and pharmacokinetics. Exploratory outcomes in PD participants included clinical measures of PD state, GI function, and cerebrospinal fluid (CSF) concentration. Results 108 patients were treated with no dropouts. The SAD tested doses ranging from 12.5 to 325 mg, while the MAD tested 25 to 200 mg and MAD-PD tested 50 to 100 mg in Parkinson's participants. All active doses had a favorable safety profile with no clinically meaningful adverse events. Single dose pharmacokinetics were approximately linear between 12.5 mg and 200 mg for both Cmax and AUC0 - inf without distinction between healthy volunteers and participants with PD. Exposures at each dose were high relative to other drugs in the same kinase inhibitor class. Conclusions Risvodetinib (IkT-148009) was well tolerated, had a favorable safety and pharmacology profile over 7-day dosing, did not induce serious adverse events and did not appear to induce deleterious side-effects in participants administered anti-PD medications.
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Affiliation(s)
| | - C Warren Olanow
- Department of Neurology and Neuroscience, Mount Sinai School of Medicine, New York, NY, USA
- Clintrex Research Corporation, Sarasota, FL, USA
| | - Andrew McGarry
- Clintrex Research Corporation, Sarasota, FL, USA
- Cooper Medical School at Rowan University/Cooper University Healthcare, Camden, NJ, USA
| | | | | | - Carl Klint
- Inhibikase Therapeutics, Inc., Atlanta, GA, USA
| | | | | | - Larry Ereshefsky
- Follow the Molecule, Marina del Rey, CA, USA
- CenExcel, Salt Lake City, UT, USA
| | - Lawrence Blob
- Cognitive Research Institute, St. Petersberg, FL, USA
| | | | | | - Emil Samara
- PharmaPolaris International, Inc., Danville, CA, USA
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Cascino GD, Tarquinio D, Wheless JW, Hogan RE, Sperling MR, Desai J, Vazquez B, Samara E, Misra SN, Carrazana E, Rabinowicz AL. Lack of Clinically Relevant Differences in Safety and Pharmacokinetics After Second-Dose Administration of Intranasal Diazepam Within 4 Hours for Acute Treatment of Seizure Clusters: A Population Analysis. Epilepsia 2022; 63:1714-1723. [PMID: 35377464 PMCID: PMC9543781 DOI: 10.1111/epi.17249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/01/2022] [Accepted: 04/01/2022] [Indexed: 11/30/2022]
Abstract
Objective Current diazepam nasal spray labeling requires waiting 4 h before administering a second dose. The objective of the current analyses was to examine safety and pharmacokinetic profiles of second doses of diazepam nasal spray given 0−4 h after the first dose. Methods Two datasets were analyzed. The first, a long‐term, repeat‐dose safety study of diazepam nasal spray, compared rates of treatment‐emergent adverse events (TEAEs), serious TEAEs, and treatment‐related TEAEs for patients receiving ≥1 second dose ≤4 h versus all second doses >4 h after the first. The second was a population pharmacokinetic analysis using data from three phase 1 studies to model drug exposure when a second dose of diazepam nasal spray was administered across multiple time points (1 min−4 h) following the first dose. Results In the repeat‐dose safety study, a second dose of diazepam nasal spray was administered ≤24 h after the first to treat 485 seizure clusters in 79 patients. Rates of TEAEs were similar between patients receiving ≥1 second dose in ≤4 h (89.5%, n = 38) compared with >4–24 h only (80.5%, n = 41). The most common treatment‐related TEAEs were associated with nasal discomfort, which was mild or moderate and transient. There were no reports of respiratory or cardiac depression. The pharmacokinetic simulations of second doses predicted comparable elevations of plasma diazepam concentrations with administrations across a range of intervals after the first dose (1 min−4 h). Significance These data indicate that the safety and pharmacokinetic profiles of a second dose of diazepam nasal spray administered within 4 h of the first dose are consistent with those associated with current labeling. This is potentially important for patients with seizure clusters who have a recurrent seizure within 4 h of first treatment and might benefit from immediate retreatment to reduce the risk of progression to status epilepticus.
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Affiliation(s)
| | | | - James W Wheless
- Le Bonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, TN, USA
| | | | | | - Jay Desai
- Children's Hospital of Los Angeles, CA, USA
| | - Blanca Vazquez
- New York University, Comprehensive Epilepsy Center, New York, NY, USA
| | - Emil Samara
- PharmaPolaris International, Inc, Washington, DC, USA
| | | | - Enrique Carrazana
- Neurelis, Inc., San Diego, CA, USA.,John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
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3
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Samara E, Constantin C. Analysis of rejected radiological images across 5 centres. Phys Med 2021. [DOI: 10.1016/s1120-1797(22)00067-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Borthakur G, Ofran Y, Tallman MS, Foran J, Uy GL, DiPersio JF, Showel MM, Shimoni A, Nagler A, Rowe JM, Altman JK, Abraham M, Peled A, Shaw S, Bohana-Kashtan O, Sorani E, Pereg Y, Foley-Comer A, Oberkovitz G, Lustig TM, Glicko-Kabir I, Aharon A, Vainstein-Haras A, Kadosh SE, Samara E, Al-Rawi AN, Pemmaraju N, Bueso-Ramos C, Cortes JE, Andreeff M. BL-8040 CXCR4 antagonist is safe and demonstrates antileukemic activity in combination with cytarabine for the treatment of relapsed/refractory acute myelogenous leukemia: An open-label safety and efficacy phase 2a study. Cancer 2020; 127:1246-1259. [PMID: 33270904 DOI: 10.1002/cncr.33338] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND CXCR4 mediates the retention and survival of acute myelogenous leukemia blasts in bone marrow and contributes to their resistance to chemotherapy. The authors evaluated a combination of the high-affinity CXCR4 antagonist BL-8040 with high-dose cytarabine (HiDAC) chemotherapy in a phase 2a study of patients with relapsed and refractory AML. METHODS Forty-two patients received treatment with BL-8040 monotherapy for 2 days followed by a combination of BL-8040 with HiDAC for 5 days. Six escalating BL-8040 dose levels were investigated (0.5, 0.75, 1.0, 1.25, 1.5, and 2.0 mg/kg), and 1.5 mg/kg was selected as the dose for the expansion phase (n = 23). RESULTS BL-8040 in combination with HiDAC was safe and well tolerated at all dose levels. Clinical response was observed with BL-8040 doses ≥1.0 mg/kg. The composite response rate (complete remissions plus complete remissions with incomplete hematologic recovery of platelets or neutrophils) was 29% (12 of 42) in all patients and 39% (9 of 23) in the 1.5-mg/kg phase. The median overall survival was 8.4 months for all patients, 10.8 months in the 1.5-mg/kg phase, and 21.8 months for responding patients in the 1.5-mg/kg cohort. Two days of BL-8040 monotherapy triggered the mobilization of blasts into peripheral blood, with significantly higher mean fold-changes in responders versus nonresponders. This was accompanied by a decrease in bone marrow blasts. CONCLUSIONS The current results demonstrate the efficacy of CXCR4 targeting with BL-8040 and support continued clinical development in acute myelogenous leukemia.
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Affiliation(s)
- Gautam Borthakur
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Yishai Ofran
- Laboratory of genetic and immunology of Leukemia, Rambam Medical Center, Haifa, Israel
| | | | - James Foran
- Cancer center, Bone Marrow Transplant Program, Hematology, Mayo Clinic, Jacksonville, Florida
| | - Geoffrey L Uy
- Oncology Division Bone Marrow Transplantation & Leukemia, Washington University School of Medicine, St Louis, Missouri
| | - John F DiPersio
- Oncology Division Bone Marrow Transplantation & Leukemia, Washington University School of Medicine, St Louis, Missouri
| | | | - Avichai Shimoni
- Division of Hematology, Chaim Sheba Medical Center, Ramat-Gan, Israel
| | - Arnon Nagler
- Division of Hematology, Chaim Sheba Medical Center, Ramat-Gan, Israel
| | | | - Jessica K Altman
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois
| | - Michal Abraham
- Biokine Therapeutics Ltd, Ness Ziona, Israel.,Goldyne Savad Institute of Gene Therapy, Hebrew University Hospital, Jerusalem, Israel
| | - Amnon Peled
- Biokine Therapeutics Ltd, Ness Ziona, Israel.,Goldyne Savad Institute of Gene Therapy, Hebrew University Hospital, Jerusalem, Israel
| | | | | | | | | | | | | | | | | | | | | | | | - Emil Samara
- PharmaPolaris International Inc, Washington, District of Columbia
| | - Ahmed N Al-Rawi
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Naveen Pemmaraju
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Carlos Bueso-Ramos
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jorge E Cortes
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Michael Andreeff
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Samara E, Twohig E. A new manifestation of Job's syndrome in the orofacial region. Br J Oral Maxillofac Surg 2019; 58:120-121. [PMID: 31668864 DOI: 10.1016/j.bjoms.2019.10.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/08/2019] [Indexed: 11/29/2022]
Affiliation(s)
- E Samara
- Honorary Clinical Tutor Speciality Dentsit Oral Surgery Birmingham Dental Hospital, Birmingham, UK.
| | - E Twohig
- Worcestershire Royal Hospital, Worcester, UK.
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Wates E, Ria B, Samara E, Higginson J. Urgent oral and maxillofacial surgery in the pregnant patient: a review of the literature. Int J Oral Maxillofac Surg 2019. [DOI: 10.1016/j.ijom.2019.03.214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Samara E, Williams M, Howlett D. Current applications of ultrasound-guided wire localization in head and neck surgery. Int J Oral Maxillofac Surg 2019; 48:443-446. [DOI: 10.1016/j.ijom.2018.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/27/2018] [Accepted: 09/27/2018] [Indexed: 11/16/2022]
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Spiegelstein O, Mimrod D, Rabinovich L, Eyal E, Sprenger C, Elgart A, Samara E, Morganroth J. A Thorough QT/QTc Study With Laquinimod, a Novel Immunomodulator in Development for Multiple Sclerosis and Huntington Disease. Clin Pharmacol Drug Dev 2018; 8:49-59. [DOI: 10.1002/cpdd.442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/20/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Ofer Spiegelstein
- Clinical Pharmacology and Pharmacometrics; Teva Pharmaceutical Industries Ltd; Netanya Israel
| | - Dorit Mimrod
- Project Leadership; Teva Pharmaceutical Industries Ltd; Netanya Israel
| | - Laura Rabinovich
- Clinical Pharmacology and Pharmacometrics; Teva Pharmaceutical Industries Ltd; Frazer PA USA
| | - Eli Eyal
- Global Biostatistics Unit; TEVA Pharmaceutical Industries Ltd; Netanya Israel
| | | | - Anna Elgart
- Clinical Pharmacology and Pharmacometrics; Teva Pharmaceutical Industries Ltd; Netanya Israel
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Chloros T, Douma A, Makrypodi M, Andreeva A, Samara E, Dimakopoulou A. Dexmedetomidine sedation for non-elective, awake airway management – A case series. Trends in Anaesthesia and Critical Care 2017. [DOI: 10.1016/j.tacc.2017.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ziemssen T, Tumani H, Sehr T, Thomas K, Paul F, Richter N, Samara E, Spiegelstein O, Sorani E, Bar-Ilan O, Mimrod D, Hayardeny L. Safety and in vivo immune assessment of escalating doses of oral laquinimod in patients with RRMS. J Neuroinflammation 2017; 14:172. [PMID: 28859672 PMCID: PMC5577769 DOI: 10.1186/s12974-017-0945-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/16/2017] [Indexed: 11/18/2022] Open
Abstract
Background Laquinimod is an oral immunomodulator in clinical development to treat relapsing-remitting multiple sclerosis (RRMS). Laquinimod is in clinical development for the treatment of multiple sclerosis and Huntington Disease (HD). The objective of this study is to assess the safety, tolerability, pharmacokinetics (PK) and cytoimmunologic effects following escalating doses of laquinimod in patients with RRMS. Methods One hundred twelve patients were randomly assigned to laquinimod/placebo in a series of separate dose-escalating cohorts starting from a daily oral dose of 0.9 mg/1.2 mg escalating to 2.7 mg, in 0.3 mg increments. Results Twenty-eight patients received placebo and 84 received laquinimod ranging from 0.9 to 2.7 mg. No deaths occurred. One serious adverse event (SAE) of perichondritis was reported, which was unrelated to laquinimod (0.9 mg). There was no increased incidence of adverse events (AEs) with escalating doses. Laquinimod-treated patients showed more abnormal laboratory levels in liver enzymes, P-amylase, C-reactive protein (CRP), and fibrinogen, but most shifts were clinically non-significant. The exposure of laquinimod was dose proportional and linear in the tested dose range. An immunological substudy showed significant dose-dependent decreases in 6-sulpho LacNAc + dendritic cell (slanDC) frequency following laquinimod compared to placebo. Conclusion Laquinimod doses up to 2.7 mg were safely administered to patients with RRMS. An in vivo effect of laquinimod on the innate immune system was demonstrated. Trial registration EudraCT Number: 2009-011234-99. Registered 23 June 2009. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0945-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tjalf Ziemssen
- Department of Neurology, MS Center Dresden, Center of Clinical Neuroscience, University Clinic Carl Gustav Carus Dresden, Dresden, Germany.
| | - Hayrettin Tumani
- Multiple Sclerosis Unit, Department of Neurology, University of Ulm, Ulm, Germany. .,Fachklinik für Neurologie Dietenbronn, Schwendi, Germany.
| | - Tony Sehr
- Department of Neurology, MS Center Dresden, Center of Clinical Neuroscience, University Clinic Carl Gustav Carus Dresden, Dresden, Germany
| | - Katja Thomas
- Department of Neurology, MS Center Dresden, Center of Clinical Neuroscience, University Clinic Carl Gustav Carus Dresden, Dresden, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center and Clinical and Experimental Multiple Sclerosis Research Center, Department of Neurology, Charité University Medicine, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité University Medicine Berlin, Berlin, Germany
| | - Nils Richter
- Neurologische Gemeinschaftspraxis, Düsseldorf, Germany
| | | | | | - Ella Sorani
- Teva Pharmaceutical Industries, Netanya, Israel
| | | | | | - Liat Hayardeny
- Teva Pharmaceutical Industries, Netanya, Israel.,Galmed Pharmaceuticals, Tel Aviv, Israel
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Moriarty TF, Schmid T, Post V, Samara E, Kates S, Schwarz EM, Zeiter S, Richards RG, Richards RG. A large animal model for a failed two-stage revision of intramedullary nail-related infection by methicillin-resistant Staphylococcus aureus. Eur Cell Mater 2017; 34:83-98. [PMID: 28853767 DOI: 10.22203/ecm.v034a06] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The treatment of chronic orthopaedic device-associated infection (ODRI) often requires multiple surgeries and prolonged antibiotic therapy. Despite this extensive treatment protocol, the procedure is associated with significant failure rates. Currently, no large animal model is available that recapitulates a failed revision. Therefore, our aim was to establish a large animal model for failed treatment of an ODRI in order to serve as a testbed for future interventional strategies. Adult Swiss Alpine sheep received an intramedullary nail in the tibia and a localised inoculum of either a methicillin-sensitive or methicillin-resistant Staphylococcus aureus (MSSA, MRSA respectively). After 8 weeks, when chronic infection had been established, the animals underwent a staged revision with debridement and temporary placement of an antibiotic-loaded cement spacer. Antibiotics were delivered systemically in a standard or pathogen-adapted manner. Debridement and implant exchange alone failed to treat the MSSA infection. Neither local therapy alone nor systemic therapy alone were effective in resolving infection with MSSA, but a combination of local and systemic therapy was effective against it. MRSA infection was not resolved by the combination of local and systemic antibiotics (standard or pathogen-adapted). A model for failed revision of MRSA infection is described despite the use of local and systemic antibiotics. Novel interventions may be assessed using this model, including antibiotic and non-antibiotic interventions.
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12
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Samara E, Moriarty TF, Decosterd LA, Richards RG, Gautier E, Wahl P. Antibiotic stability over six weeks in aqueous solution at body temperature with and without heat treatment that mimics the curing of bone cement. Bone Joint Res 2017; 6:296-306. [PMID: 28515059 PMCID: PMC5457644 DOI: 10.1302/2046-3758.65.bjr-2017-0276.r1] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/27/2017] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Thermal stability is a key property in determining the suitability of an antibiotic agent for local application in the treatment of orthopaedic infections. Despite the fact that long-term therapy is a stated goal of novel local delivery carriers, data describing thermal stability over a long period are scarce, and studies that avoid interference from specific carrier materials are absent from the orthopaedic literature. METHODS In this study, a total of 38 frequently used antibiotic agents were maintained at 37°C in saline solution, and degradation and antibacterial activity assessed over six weeks. The impact of an initial supplementary heat exposure mimicking exothermically curing bone cement was also tested as this material is commonly used as a local delivery vehicle. Antibiotic degradation was assessed by liquid chromatography coupled to mass spectrometry, or by immunoassays, as appropriate. Antibacterial activity over time was determined by the Kirby-Bauer disk diffusion assay. RESULTS The heat exposure mimicking curing bone cement had minimal effect on stability for most antibiotics, except for gentamicin which experienced approximately 25% degradation as measured by immunoassay. Beta-lactam antibiotics were found to degrade quite rapidly at 37°C regardless of whether there was an initial heat exposure. Excellent long-term stability was observed for aminoglycosides, glycopeptides, tetracyclines and quinolones under both conditions. CONCLUSIONS This study provides a valuable dataset for orthopaedic surgeons considering local application of antibiotics, and for material scientists looking to develop next-generation controlled or extended-release antibiotic carriers.Cite this article: E. Samara, T. F. Moriarty, L. A. Decosterd, R. G. Richards, E. Gautier, P. Wahl. Antibiotic stability over six weeks in aqueous solution at body temperature with and without heat treatment that mimics the curing of bone cement. Bone Joint J 2017;6:296-306. DOI: 10.1302/2046-3758.65.BJR-2017-0276.R1.
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Affiliation(s)
- E Samara
- AO Research Institute Davos, Davos, Switzerland
| | | | - L A Decosterd
- Head of the Laboratory of Clinical Pharmacology, University Hospital Lausanne and University of Lausanne, Lausanne, Switzerland
| | | | - E Gautier
- Head of the Department of Orthopaedic Surgery, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland
| | - P Wahl
- Division for Orthopaedic and Trauma Surgery, Cantonal Hospital Winterthur, Winterthur, Switzerland
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Wilsey BL, Deutsch R, Samara E, Marcotte TD, Barnes AJ, Huestis MA, Le D. A preliminary evaluation of the relationship of cannabinoid blood concentrations with the analgesic response to vaporized cannabis. J Pain Res 2016; 9:587-98. [PMID: 27621666 PMCID: PMC5012851 DOI: 10.2147/jpr.s113138] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A randomized, placebo-controlled crossover trial utilizing vaporized cannabis containing placebo and 6.7% and 2.9% delta-9-tetrahydrocannabinol (THC) was performed in 42 subjects with central neuropathic pain related to spinal cord injury and disease. Subjects received two administrations of the study medication in a 4-hour interval. Blood samples for pharmacokinetic evaluation were collected, and pain assessment tests were performed immediately after the second administration and 3 hours later. Pharmacokinetic data, although limited, were consistent with literature reports, namely dose-dependent increase in systemic exposure followed by rapid disappearance of THC. Dose-dependent improvement in pain score was evident across all pain scale elements. Using mixed model regression, an evaluation of the relationship between plasma concentrations of selected cannabinoids and percent change in items from the Neuropathic Pain Scale was conducted. Changes in the concentration of THC and its nonpsychotropic metabolite, 11-nor-9-carboxy-THC, were related to percent change from baseline of several descriptors (eg, itching, burning, and deep pain). However, given the large number of multiple comparisons, false-discovery-rate-adjusted P-values were not significant. Plans for future work are outlined to explore the relationship of plasma concentrations with the analgesic response to different cannabinoids. Such an appraisal of descriptors might contribute to the identification of distinct pathophysiologic mechanisms and, ultimately, the development of mechanism-based treatment approaches for neuropathic pain, a condition that remains difficult to treat.
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Affiliation(s)
- Barth L Wilsey
- VA Northern California Health Care System, Mather, CA; Department of Physical Medicine and Rehabilitation, University of California, Sacramento, CA
| | - Reena Deutsch
- Department of Psychiatry, University of California, San Diego, La Jolla, CA
| | | | - Thomas D Marcotte
- Department of Psychiatry, University of California, San Diego, La Jolla, CA
| | - Allan J Barnes
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, Baltimore, MD
| | - Marilyn A Huestis
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, Baltimore, MD; University of Maryland School of Medicine, Baltimore, MD, USA
| | - Danny Le
- VA Northern California Health Care System, Mather, CA; Department of Physical Medicine and Rehabilitation, University of California, Sacramento, CA
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Sy SKB, Asin-Prieto E, Derendorf H, Samara E. Predicting pediatric age-matched weight and body mass index. AAPS J 2014; 16:1372-9. [PMID: 25155824 DOI: 10.1208/s12248-014-9657-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 08/05/2014] [Indexed: 01/30/2023]
Abstract
The empirical scaling from adult to pediatric using allometric size adjustments based on body weight continued to be the mainstream method for pediatric dose selection. Due to the flexibility of a polynomial function to conform to the data trend, an empirical function for simulating age-matched weight and body mass index by gender in the pediatric population is developed by using a polynomial function and a constant coefficient to describe the interindividual variability in weight. A polynomial of up to fifth order sufficiently described the pediatric data from the Center for Disease Control (CDC) and the World Health Organization (WHO). The coefficients of variation to describe the variability were within 17%. The percentages of the CDC simulated weights for pediatrics between 0 and 5 years that fell outside the WHO 90% and 95% confidence boundaries were well within the expected percentage values, indicating that the CDC dataset can be used to substitute for the WHO dataset for the purpose of pediatric drug development. To illustrate the utility of this empirical function, the CDC-based age-matched weights were simulated and were used in the prediction of the concentration-time profiles of tenofovir in children based on a population pharmacokinetic model whose parameters were allometrically scaled. We have shown that the resulting 95% prediction interval of tenofovir in newborn to 5 years of age was almost identical whether the weights were simulated based on WHO or CDC dataset. The approach is simple and is broadly applicable in adjusting for pediatric dosages using allometry.
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Affiliation(s)
- Sherwin K B Sy
- Department of Pharmaceutics, College of Pharmacy, University of Florida, 1345 Center Drive, PO Box 100494, Gainesville, Florida, 32610, USA
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Aza E, Caresana M, Cassell C, Charitonidis N, Harrouch E, Manessi G, Pangallo M, Perrin D, Samara E, Silari M. Instrument intercomparison in the pulsed neutron fields at the CERN HiRadMat facility. RADIAT MEAS 2014. [DOI: 10.1016/j.radmeas.2013.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Samara E, Winkle P, Pardo P, Henney HR, Way SL, Brown E, Lee A, Blight AR. Pharmacokinetics of dalfampridine extended release 7.5-mg tablets in healthy subjects and individuals with mild and moderate renal impairment: an open-label study. J Clin Pharmacol 2014; 54:53-60. [PMID: 24150835 PMCID: PMC4263161 DOI: 10.1002/jcph.189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 09/17/2013] [Indexed: 11/08/2022]
Abstract
Dalfampridine extended release tablets (D-ER; prolonged-release fampridine in Europe) are available to improve walking in patients with multiple sclerosis (MS). D-ER is mainly renally eliminated; the approved 10-mg twice daily dose is contraindicated in the United States in patients with moderate or severe renal impairment. This study evaluated single-dose and steady-state pharmacokinetics of a 7.5-mg dose of D-ER in healthy subjects (n = 13) and subjects with mild (n = 17) and moderate (n = 12) renal impairment. D-ER plasma concentrations were consistently higher in subjects with renal impairment relative to healthy individuals with a significant (P < .0001) inverse linear relationship between creatinine clearance and drug exposure. Steady-state AUC0-12 among healthy subjects, 167.0 ± 55.3 ng h/mL, increased 74% and 151% with mild and moderate renal impairment, respectively. The overall incidence of adverse events was 61.5%, 47.1%, and 33.3% in healthy subjects, and subjects with mild and moderate renal impairment, respectively, and for treatment-related adverse events the rates were 0%, 17.6%, and 8.3%, respectively. The most common adverse events were headache, dizziness, and arthralgia. The pharmacokinetics of D-ER 7.5-mg twice daily in subjects with mild renal impairment was comparable to 10-mg twice daily in patients with MS who had normal renal function. Exposure was significantly higher in moderate renal impairment.
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Affiliation(s)
| | | | | | | | | | | | - Angela Lee
- Acorda Therapeutics, Inc.Ardsley, NY, USA
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17
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Baluom M, Samara E, Grossbard EB, Lau DTW. Fostamatinib, a Syk-kinase inhibitor, does not affect methotrexate pharmacokinetics in patients with rheumatoid arthritis. J Clin Pharmacol 2011; 51:1310-8. [PMID: 21209239 DOI: 10.1177/0091270010381496] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fostamatinib (R788) is being investigated as an add-on therapy for the treatment of rheumatoid arthritis (RA) in patients with inadequate response to methotrexate (MTX). This study evaluated the potential pharmacokinetic interaction between R788 and MTX. Sixteen RA subjects on a stable weekly MTX regimen were enrolled and received MTX on days 1 and 8. Twelve subjects received 100 mg of R788 orally, and 4 subjects received a matching placebo twice daily from days 4 to 8 and once daily on days 3 and 9. Blood samples were collected on days 1 and 8 for MTX and 7-hydroxymethotrexate (7-OH-MTX), and days 3 and 9 for R788 and its active metabolite, R406. MTX and 7-OH-MTX pharmacokinetic parameters were similar on days 1 and 8. In the R788 group, the mean day 8 to day 1 ratios (90% confidence intervals) of maximum concentration and area under the plasma concentration-time curve estimates were 1.01 (0.85-1.20) and 1.12 (0.90-1.40) for MTX and 1.06 (0.82-1.35) and 1.06 (0.83-1.36) for 7-OH-MTX, respectively. Urinary excretion of MTX and 7-OH-MTX was also similar with or without R788, averaging 58% to 69% and 4% to 5% of the MTX dose, respectively. The data suggest that there is no clinically significant pharmacokinetic interaction of R788 and MTX in RA patients.
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Affiliation(s)
- Muhammad Baluom
- Rigel Pharmaceuticals, Inc, 1180 Veterans Blvd., South San Francisco, CA 94080, USA
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18
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Treier R, Aroua A, Verdun FR, Samara E, Stuessi A, Trueb PR. Patient doses in CT examinations in Switzerland: implementation of national diagnostic reference levels. Radiat Prot Dosimetry 2010; 142:244-254. [PMID: 20926508 DOI: 10.1093/rpd/ncq279] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerland.
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Affiliation(s)
- R Treier
- Radiation Protection Division, Federal Office of Public Health, 3003 Bern, Switzerland.
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19
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Dutta S, Qiu Y, Samara E, Cao G, Granneman GR. Once-a-Day Extended-Release Dosage form of Divalproex Sodium III: Development and Validation of a Level A in Vitro–in Vivo Correlation (IVIVC). J Pharm Sci 2005; 94:1949-56. [PMID: 16052544 DOI: 10.1002/jps.20387] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Defining a quantitative and reliable relationship between in vitro drug release and in vivo absorption is highly desired for rational development, optimization, and evaluation of controlled-release dosage forms and manufacturing process. During the development of a once-daily extended-release (ER) tablet of divalproex sodium, a predictive in vitro drug release method was designed and statistically evaluated using three formulations with varying release rates. In order to establish an internally and externally validated Level A IVIVC, a total of five different ER formulations of divalproex sodium were used to evaluate a linear IVIVC model based on the in vitro test method. For internal validation, a single-dose four-way crossover study (N = 16) was performed using fast-, medium-, and slow-releasing ER formulations and a 12-h IV infusion of valproic acid as reference. To validate the IVIVC externally, a second three-way crossover study (N = 36) was performed using slightly-fast-, medium-, and slightly-slow-releasing ER formulations. The in vivo absorption-time profile was inferred by deconvolution of the observed plasma concentration-time profiles against the unit disposition function (UDF). A linear IVIVC model was established in which the in vivo absorption was expressed as a function of in vitro drug release. Plasma profiles of ER formulations were estimated via convolution of in vitro release profiles with the UDF. Successful internal and external validations of the model were demonstrated by individual and average absolute percent prediction errors of </=9% for both C(max) and AUC(infinity). In conclusion, a Level A IVIVC describing the entire time-course of plasma concentrations was developed and validated, both internally and externally, for ER formulations of divalproex sodium.
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Affiliation(s)
- Sandeep Dutta
- Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois 60064, USA.
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20
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Lee SH, Lopes de Menezes D, Vora J, Harris A, Ye H, Nordahl L, Garrett E, Samara E, Aukerman SL, Gelb AB, Heise C. In vivoTarget Modulation and Biological Activity of CHIR-258, a Multitargeted Growth Factor Receptor Kinase Inhibitor, in Colon Cancer Models. Clin Cancer Res 2005; 11:3633-41. [PMID: 15897558 DOI: 10.1158/1078-0432.ccr-04-2129] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate the therapeutic and biological effects of CHIR-258, an orally bioavailable, potent inhibitor of class III-V receptor tyrosine kinases, in colon cancer models. EXPERIMENTAL DESIGN The pharmacologic activity of CHIR-258 was characterized by monitoring target modulation as well as by evaluating the antitumor and antiangiogenic effects in human colon xenograft models. RESULTS CHIR-258 inhibits vascular endothelial growth factor receptor 1/2, fibroblast growth factor receptor 1/3, and platelet-derived growth factor receptor beta (PDGFRbeta) and shows both antitumor and antiangiogenic activities in vivo. Treatment of KM12L4a human colon cancer cells with CHIR-258 resulted in a dose-dependent inhibition of vascular endothelial growth factor receptor 1 and PDGFRbeta phosphorylation and reduction of phosphorylated extracellular signal-regulated kinase (ERK) levels, indicating modulation of target receptors and downstream signaling. In vivo administration of CHIR-258 resulted in significant tumor growth inhibition and tumor regressions, including large, established tumors (500-1,000 mm(3)). Immunohistochemical analysis showed a reduction of phosphorylated PDGFRbeta and phosphorylated ERK in tumor cells after oral dosing with CHIR-258 compared with control tumors. These changes were accompanied by decreased tumor cell proliferation rate and reduced intratumoral microvessel density. CHIR-258 inhibited the phosphorylation of PDGFRbeta and ERK phosphorylation in tumors within 2 hours following dosing and the inhibitory activity was sustained for >24 hours. Significant antitumor activity was observed with intermittent dosing schedules, indicating a sustained biological activity. CONCLUSION These studies provide evidence that biological activity of CHIR-258 in tumors correlates with efficacy and aids in the identification of potential biomarkers of this multitargeted receptor tyrosine kinase inhibitor. CHIR-258 exhibits properties that make it a promising candidate for clinical development in a variety of solid and hematologic malignancies.
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Affiliation(s)
- Sang Hoon Lee
- Department of Pharmacology, Chiron Corp., Emeryville, California, USA
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21
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Qiu Y, Garren J, Samara E, Cao G, Abraham C, Cheskin HS, Engh KR. Once‐a‐Day Controlled‐Release Dosage Form of Divalproex Sodium II: Development of a Predictive In Vitro Drug Release Method. J Pharm Sci 2003; 92:2317-25. [PMID: 14603516 DOI: 10.1002/jps.10486] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During formulation design of a once-daily controlled release matrix system of divalproex sodium, the in vitro dissolution test (USP II, 100 rpm, pH 6.8 buffer) was found to result in release rates that were slower than in vivo absorption. The test method also did not sufficiently discriminate formulations with different in vivo absorption rates. To develop an in vitro method that is directly correlated with in vivo absorption, statistically designed studies were carried out to investigate the effects of various in vitro testing variables on drug release using USP dissolution apparatuses. The variables studied included agitation intensity, apparatus, pH, surfactant and ionic strength of the dissolution medium. Experimental data were analyzed using ANOVA. In vitro/in vivo correlation was tested based on the hypothesis that the same linear regression equation holds for three formulations with different release rates. A mixed effects model was used in which the dependence among observations from the same subject was taken into account. Factorial studies indicated that higher pH, addition of sodium lauryl sulphate (SLS) to the dissolution medium, and higher agitation intensity increased the release rate from the matrix tablet. Use of SLS not only lead to increased release rates that are more comparable to in vivo absorption rates, but also improved differentiation among formulations with varying release rates. Furthermore, drug release was also affected by interactions among the variables studied. Statistical analysis indicated that a combination of higher SLS concentration and lower pH provided enhanced differentiation between release profiles of the fast and slow releasing formulations. Based on the above findings, a new set of testing conditions was identified and demonstrated to be predictive of in vivo drug absorption for various controlled release formulations of divalproex sodium. The new method uses USP Apparatus II operating at 100 rpm in 500 mL of 0.1 N HCl for 45 min followed by 900 mL of 0.05 M phosphate buffer containing 75 mM SLS, pH 5.5, 37 +/- 0.5 degrees C. In conclusion, adjusting dissolution testing conditions to match the behavior of the formulations in vitro with that in vivo is a useful approach in identifying a predictive method in development of in vitro-in vivo correlation.
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Affiliation(s)
- Yihong Qiu
- Formulation Development Center, Global Pharmaceutical Research and Development, Abbott Laboratories, R-4P7/R1B, 1401 N. Sheridan Rd., North Chicago, Illinois 60064, USA.
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Abstract
The pharmacokinetics of 1, 10, 23.25, and 139.5 mg doses of atrasentan was assessed in a placebo-controlled, double-blind, single oral dose study in 24 healthy male subjects. Atrasentan was well tolerated. Atrasentan pharmacokinetics was linear in the 1 to 23.25 mg dose range, with some dose dependency in the highest dose group. Harmonic mean terminal half-life was similar across all dose groups (20-25 h). Apparent oral clearance was low (12 L/h) for the highest dose group compared with the other three dose groups (21-27 L/h). The apparent volume of distribution was large (approximately 6 L/kg), consistent with extensive tissue distribution.
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Affiliation(s)
- E Samara
- Abbott Laboratories, Abbott Park, Illinois, USA
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23
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Bush MA, Samara E, Whitehouse MJ, Yoshizawa C, Novicki DL, Pike M, Laham RJ, Simons M, Chronos NA. Pharmacokinetics and pharmacodynamics of recombinant FGF-2 in a phase I trial in coronary artery disease. J Clin Pharmacol 2001; 41:378-85. [PMID: 11304894 DOI: 10.1177/00912700122010230] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fibroblast growth factor-2 (FGF-2) is a heparin-binding protein capable of inducing angiogenesis in multiple animal models of chronic ischemia. The pharmacokinetics and pharmacodynamics of a single dose of recombinant FGF-2 (rFGF-2) administered by intracoronary or intravenous infusion were evaluated in a Phase I trial in 66 patients with severe coronary artery disease. rFGF-2 displayed biphasic elimination with a mean studywide distribution t1/2 of 21 minutes and a mean apparent terminal elimination t1/2 of 7.6 hours. Systemic exposure to rFGF-2 was comparable following intracoronary or intravenous administration. Peak plasma concentration and area under the concentration-time curve increased proportionally with dose, indicating linear pharmacokinetics over the dose range examined (0.33 to 48.0 micrograms/kg). Greater systemic exposure was observed when heparin was administered closer to rFGF-2 infusion, consistent with slower clearance of heparin/rFGF-2 complexes. Infusion of rFGF-2 was associated with changes in acute hemodynamics. While a clear PK/PD dose-response relationship was not established, a trend toward hypotension and tachycardia with higher rFGF-2 doses was observed.
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Affiliation(s)
- M A Bush
- Chiron Corporation, 4560 Horton Street M/S 4. 178, Emeryville, CA 94608-2916, USA
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Singh M, Shirley B, Bajwa K, Samara E, Hora M, O'Hagan D. Controlled release of recombinant insulin-like growth factor from a novel formulation of polylactide-co-glycolide microparticles. J Control Release 2001; 70:21-8. [PMID: 11166404 DOI: 10.1016/s0168-3659(00)00313-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of the current study was to develop a controlled-release delivery system for recombinant insulin-like growth factor (rhIGF-I). Polylactide-co-glycolide (PLG) microparticles with entrapped rhIGF-I were prepared by a novel emulsion based solvent evaporation process. Microparticles with two loading levels of rhIGF-I were prepared (4 and 20% w/w). The integrity of released rhIGF-I was characterized by RP-HPLC, SDS-PAGE and a bioactivity assay. In vitro and in vivo release profiles of rhIGF-I from these microparticles were also evaluated. Reproducible batches of microparticles with 4% and 20% w/w loading of rhIGF-I were prepared, with excellent encapsulation efficiency (81 and 85% of total protein respectively entrapped). The protein retained integrity after the microencapsulation process as evaluated by RP-HPLC, SDS-PAGE and bioactivity assay. The in vitro profiles exhibited a significant burst release of rhIGF-I (20-30%), followed by controlled release of protein for up to 28 days. A similar level of burst release was observed in vivo, followed by controlled release of protein for 14-18 days. In addition, there was a surprisingly close correlation between in vitro and in vivo release rates. PLG microparticles with entrapped rhIGF-I are a promising delivery system which may allow rhIGF-I to be used for a broad range of therapeutic indications.
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Affiliation(s)
- M Singh
- Chiron Corporation, 4560 Horton Street, Emeryville, CA 94608, USA.
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25
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Dutta S, Samara E, Lam W, Granneman G, Leese PT, Padley R. Multiple-Dose Pharmacokinetics of Atrasentan, an Endothelin-A Receptor Antagonist. Clin Drug Investig 2001. [DOI: 10.2165/00044011-200121020-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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26
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Arendar G, Samara E, Palmas C. Neonatal acquired paraplegia: retrospective review of 30 patients. J Pediatr Orthop B 1999; 8:80-3. [PMID: 10218164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Thirty patients with neonatal acquired paraplegia without an identified cause were reviewed. The mean gestational age was 33 weeks (range, 25-40 weeks); the mean Apgar scores were 6 and 8 (range, 0-10); the mean weight at birth was 1.739 kg (range, 0.750-4.200 kg). Half of the infants needed neonatal intensive care for a mean period of 42 days. Fourteen (46%) had local or generalized infections, 12 (40%) had respiratory complications, and seven (22%) required mechanical ventilation. Seven (22%) had polycythemia, six (20%) had anemia, six (20%) underwent umbilical artery catheterization, and five (16%) received full exchange transfusion. Two clinical presentations were observed: flaccid (24 patients) and hypertonic (6 patients). The secondary deformities that were found and the orthopedic procedures to correct them are described. A vascular or intravascular change, such as thrombosis/embolism or ischemia/hypoxia by vasospasm or failure of autoregulation of spinal blood perfusion, is the final pathway of many events that may produce paraplegia in preterm and low birthweight neonates.
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Affiliation(s)
- G Arendar
- National Pediatric Hospital Juan P. Garrahan, Buenos Aires, Argentina
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27
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Samara E, Cao G, Locke C, Granneman GR, Dean R, Killian A. Population analysis of the pharmacokinetics and pharmacodynamics of seratrodast in patients with mild to moderate asthma. Clin Pharmacol Ther 1997; 62:426-35. [PMID: 9357394 DOI: 10.1016/s0009-9236(97)90121-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Seratrodast, a potent thromboxane receptor antagonist, is approved in Japan for the treatment of asthma and currently is being developed in the United States. METHODS This was a phase II, randomized, double-blind, parallel-group, placebo-controlled 15-center study of seratrodast in patients with mild to moderate asthma. A total of 183 patients were randomly assigned to receive daily doses of either placebo, or 80 mg seratrodast, or 120 mg seratrodast for 8 weeks. Pharmacokinetic and pharmacodynamic modeling was carried out by means of the population approach. A two-compartment model with zero-order input and first-order elimination best fitted the plasma concentration-time data. RESULTS AND CONCLUSIONS The pharmacokinetics of seratrodast were linear after single and multiple dosing for 8 weeks. The population estimates for oral clearance and apparent volume of distribution were 8.5 ml/hr/kg and 43.3 ml/kg, respectively. All pharmacokinetic parameters (the oral central compartment clearance, the volumes of distribution of the central and peripheral compartments, and the intercompartmental clearance) were estimated with a precision of 10% or less and were found to be associated with body weight. The residual variability was 30%. The values of oral clearance estimated in this study in male patients were similar to those previously estimated in healthy male subjects. Seratrodast at a dose of 120 mg daily produced an increase in forced expiratory volume in 1 second (FEV1) from baseline that was linearly correlated with its plasma concentrations. The average slope of the concentration-effect relationship was 0.222% and 0.470% per microgram/ml after single and multiple dosing, respectively. Interpatient variability in response was mainly affected by the initial severity of the disease. A lower percentage of predicted FEV1 (i.e., more severe obstruction) was associated with higher slopes, and greater increases in FEV1.
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Affiliation(s)
- E Samara
- Abbott Laboratories, Abbott Park, IL, USA
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28
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Abstract
Population pharmacokinetic analysis is a relatively new approach which can be used to obtain important pharmacokinetic and pharmacodynamic information from sparse data sets routinely obtained in phase II and III clinical trials, these studies typically have many patients but few observations per patient. Similarly, this approach is beneficial for studies in which intensive blood sampling is not attainable, such as in children and patients with cancer and AIDS. It was not until the late 1980s and the early 1990s that this approach (which had been introduced by Sheiner and Beal approximately 20 years earlier) gained appreciable momentum. Today many pharmaceutical companies use this approach routinely, to differing extents, during their drug development process. Advocacy by the US Food and Drug Administration for pharmacokinetic screening during phase II and III studies was an important factor in the widespread adoption of this approach. A second factor was the gradual realisation that the approach can be cost effective in revealing clinically important information about the determinants of interpatient pharmacokinetic and pharmacodynamic variability in treated patients. However, several important issues remain to be resolved (such as the optimal study design, quality of the data and user-friendly software) which could determine the future role of the population approach in drug development.
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Affiliation(s)
- E Samara
- Department of Pharmacokinetics and Biopharmaceutics, Abbott Laboratories, Abbott Park, Illinois, USA.
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29
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Abstract
The pharmacokinetics of ibuprofen diethylcarbonate (ibudice) and naproxen diethythylcarbonate (napdice), two new diethylcarbonate prodrugs of ibuprofen and naproxen, was investigated in dogs. The rationale for the development of ibudice and napdice was that esterification of the carboxylic moiety of the parent compounds would suppress gastrotoxicity without adversely affecting their anti-inflammatory activity. In addition the biotransformation of the prodrugs to the parent compounds may be utilized to achieve rate and time controlled drug delivery of the active entities. Following oral administration the diethylcarbonate esters were rapidly biotransformed to the parent compounds and no ibudice or napdice was detected in the plasma. The relative bioavailability of ibuprofen and naproxen, following oral administration of ibudice and napdice, was 96% and 74%, respectively, and the rate of absorption was not significantly different from that obtained following oral dosing of the parent compound. Stability studies in gastric and intestinal juice showed that, unlike napdice, ibudice was stable in gastric juice, with both prodrugs undergoing rapid biotransformation to their parent compounds in intestinal juice. This rapid conversion led to the lack of sustained release performance following oral administration of ibudice or napidice.
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Affiliation(s)
- E Samara
- Department of Pharmacy, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Israel
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30
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Abstract
A randomised double-blind crossover study was undertaken in 20 healthy adult male volunteers to assess the effects of multiple oral dose administration of zileuton (600mg every 6 hours for 8 days) on the single dose pharmacokinetics of phenytoin 300mg. Serial blood samples were collected up to 72 hours after phenytoin administration and plasma concentrations were determined by high performance liquid chromatography. Pharmacokinetic data were analysed utilising noncompartmental and Michaelis-Menten-based population pharmacokinetic analysis. Zileuton did not significantly alter the peak plasma concentration, time to peak plasma concentration, and area under the plasma concentration-time curve of phenytoin. Moreover, population analysis revealed no significant effect of zileuton on the Michaelis-Menten parameters of phenytoin. Thus, coadministration of multiple doses of zileuton (2.4 g/day) did not significantly affect the single dose pharmacokinetics of phenytoin.
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Affiliation(s)
- E Samara
- Pharmacokinetics and Biopharmaceutics Department, Abbott Laboratories, Abbott Park, Illinois, USA
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31
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Hussein Z, Samara E, Locke CS, Orchard MA, Ringham GL, Granneman GR. Characterization of the pharmacokinetics and pharmacodynamics of a new oral thromboxane A2-receptor antagonist AA-2414 in normal subjects: population analysis. Clin Pharmacol Ther 1994; 55:441-50. [PMID: 8162671 DOI: 10.1038/clpt.1994.54] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The pharmacokinetics and pharmacodynamics of AA-2414 [(+-)-7-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)-7-phenylheptano+ ++ ic acid] were evaluated in 39 healthy male subjects after four different oral multiple-dosing regimens. Population pharmacokinetic analysis with NONMEM showed plasma concentration-time profiles of AA-2414 to be best characterized by a two-compartment open model with zero-order input and first-order elimination. The final estimates for oral clearance, volume of distribution, and steady-state volume of distribution were 10.7 ml/hr/kg, 92.8 ml/kg, and 280 ml/kg, respectively; the corresponding coefficients of variation for interindividual variability were 21%, 10%, and 9%. The pharmacokinetic parameters were associated only with body weight. The residual variability was 25%. The ex vivo platelet aggregation response to U-46619, a thromboxane A2 mimetic, was significantly inhibited by AA-2414. The effect was found to be linearly related to plasma concentration with population estimates of 2.3 mumol/L and 2.38 for the baseline effect and slope, respectively; the corresponding coefficients of variation for interindividual variability were 22% and 38%. The residual variability was 39%. The leukotriene B4, thromboxane B2, and anti-platelet aggregation factor activity measurements were not significantly affected by administration of AA-2414.
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Affiliation(s)
- Z Hussein
- Department of Pharmacokinetics and Biopharmaceutics (D-4PK), Abbott Laboratories, Abbott Park, IL 60064
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32
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Bialer M, Hadad S, Golomb G, Barel S, Samara E, Abu Salach O, Berkman N, Danenberg HD, Ben David J, Caron D. Pharmacokinetic analysis of two new sustained-release products of diltiazem designed for twice- and once-daily treatment. Biopharm Drug Dispos 1994; 15:45-52. [PMID: 8161715 DOI: 10.1002/bdd.2510150104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The pharmacokinetics of two new sustained-release (SR) products of diltiazem, Dilapress 120 mg tablets and Dilapress 240 mg tablets, was analysed and characterized in three different studies, in comparison to the following diltiazem SR formulations: Cardizem Retard, Cardizem SR, and Cardizem CD. Dilapress 120, designated for twice-daily dosing, was found to be bioequivalent to Cardizem SR and to Cardizem Retard with mean (+/- SD) relative bioavailability values of 99 +/- 27% and 113 +/- 38%, respectively. Dilapress 240, designed for once-a-day treatment, was found to have a slower absorption rate than Cardizem SR and its extent of absorption was 56 +/- 19% relative to that of Cardizem SR. However, the bioavailability of Dilapress 240 relative to that of Cardizem CD was 118 +/- 46%, indicating that the bioavailability of Cardizem CD relative to that of Cardizem SR was only 54 +/- 29%. Diltiazem is partially available due to a saturable liver first-pass effect. A high dose of Cardizem SR may partially escape this first-pass effect and, thus, achieve a higher extent of absorption than a slower SR product. Consequently, SR products of diltiazem designed for once-daily treatment may not reach the saturation stage in the liver first-pass effect process that diltiazem is susceptible to. Consequently, a twice-daily SR product of diltiazem cannot serve as a reference for extent of absorption assessments of a once-daily SR product.
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Affiliation(s)
- M Bialer
- Department of Pharmacy, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Israel
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Hussein Z, Granneman GR, Mukherjee D, Samara E, Hogan DL, Koss MA, Isenberg JI. Age-related differences in the pharmacokinetics and pharmacodynamics of lansoprazole. Br J Clin Pharmacol 1993; 36:391-8. [PMID: 12959285 PMCID: PMC1364610 DOI: 10.1111/j.1365-2125.1993.tb00386.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. The pharmacokinetics and pharmacodynamics of lansoprazole, an antisecretory and antiulcer agent, were evaluated in 12 older (> 60 years) and 12 younger (< 60 years) healthy men. 2. Doses of lansoprazole (15 or 30 mg) or placebo were each given once daily for 7 consecutive days in this randomized, double-blind, three-way crossover study. Plasma concentrations and urinary excretion of lansoprazole and its metabolites, and gastric acid secretion were monitored after dosing on days 1 and 7 of each treatment period. 3. Within each age group, lansoprazole pharmacokinetics were linear. The mean clearance and elimination half-life of lansoprazole were about 40% lower and higher, respectively, in the older subjects (CL0: 12-14 vs 20-24 1 h(-1); t1/2,z: 1.90-2.19 vs 1.26-1.44 h). 4. At each dose level, acid secretion was more inhibited in the older group. However, the AUC associated with a 50% decrease in acid secretion was similar (849 vs 892 ng ml(-1) h) for both age groups. Multiple dosing decreased the maximum possible inhibition more in the older group than in the younger group. 5. Since the decrease in acid output associated with equivalent AUCs on day 1 was similar for the two age groups, the greater difference between day 1 and day 7 secretion in the older group indicates that recovery of secretory activity may decline with increasing age.
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Affiliation(s)
- Z Hussein
- Department of Pharmacokinetics and Biopharmaceutics, Pharmaceutical Product Research and Development Division, Abbott Laboratories, Abbott Park, IL, USA
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Abstract
Urinary metabolites of cannabidiol (CBD) were extracted from human, dog and rat urine, concentrated by chromatography on Sephadex LH-20, and identified by GC/MS. Over 50 metabolites were identified with considerable species variation. CBD was excreted in substantial concentration from human urine, both in the free state and as its glucuronide. In dog, unusual glucoside conjugates of three metabolites (4''- and 5''-hydroxy and 6-oxo-CBD), not excreted in the unconjugated state, were found as the major metabolites at early times after drug administration. Other metabolites in all three species were mainly acids. Side-chain hydroxylated derivatives of CBD-7-oic acid were particularly abundant in human urine but much less so in dog. In the latter species the major oxidized metabolites were the products of beta-oxidation with further hydroxylation at C-6. A related, but undefined pathway, resulted in loss of three carbon atoms from the side-chain of CBD in man with the production of 2''-hydroxy-tris,nor-CBD-7-oic acid. Previous experiments indicate that 3'-hydroxy-metabolites are the precursors of compounds having this side-chain. Metabolism by the epoxide-diol pathway, resulting in dihydro-diol formation from the delta-8-double bond, gave metabolites in both dog and human urine. It was concluded that CBD could be used as a probe of the mechanism of several types of biotransformation, particularly those related to carboxylic acid metabolism, as intermediates of the type not usually seen with endogenous compounds were excreted in substantial concentration.
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Affiliation(s)
- D J Harvey
- University Department of Pharmacology, Oxford, UK
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Abstract
Metabolites of CBD excreted into the bile and perfusion fluid were examined in a rat liver perfusion preparation. Metabolites were extracted with ethyl acetate and identified by GC/MS as TMS derivatives. Four mono- and five di-hydroxy metabolites were identified with major sites of metabolic attack being at C-7 and C-4". A hydroxy-ketone was detected but not fully identified. All biliary metabolites were conjugated with glucuronic acid. Urinary metabolites were studied in rats with samples taken at times to 25 h after drug administration. Unmetabolized CBD and 13 metabolites were identified by GC/MS. Major metabolites were acids with beta-oxidation being a prominent pathway. The 6- and 7-hydroxy derivatives of 4",5"-bis,nor-CBD-3"-oic acid were the most abundant compounds but substantial concentrations of the di-acids, CBD-5",7-dioic acid and 4",5"-bis,nor-CBD-3",7-dioic acid were present. Concentrations of the more highly oxidized metabolites increased with time.
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Affiliation(s)
- E Samara
- University Department of Pharmacology, Oxford, UK
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Harvey DJ, Samara E, Mechoulam R. Urinary metabolites of cannabidiol in dog, rat and man and their identification by gas chromatography-mass spectrometry. J Chromatogr 1991; 562:299-322. [PMID: 2026700 DOI: 10.1016/0378-4347(91)80587-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Urinary metabolites of cannabidiol (CBD), a non-psychoactive cannabinoid of potential therapeutic interest, were extracted from dog, rat and human urine, concentrated by chromatography on Sephadex LH-20 and examined by gas chromatography-mass spectrometry as trimethylsilyl (TMS), [2H9]TMS, methyl ester-TMS and methyloxime-TMS derivatives. Fragmentation of the metabolites under electron-impact gave structurally informative fragment ions; computer-generated single-ion plots of these diagnostic ions were used extensively to aid metabolite identification. Over fifty metabolites were identified with considerable species variation. CBD was excreted in substantial concentration in human urine, both in the free state and as its glucuronide. In dog, unusual glucoside conjugates of three metabolites (4"- and 5"-hydroxy- and 6-oxo-CBD), not excreted in the unconjugated state, were found as the major metabolites at early times after drug administration. Other metabolites in all three species were mainly acids. Side-chain hydroxylated derivatives of CBD-7-oic acid were particularly abundant in human urine but much less so in dog. In the latter species the major oxidized metabolites were the products of beta-oxidation with further hydroxylation at C-6. A related, but undefined pathway resulted in loss of three carbon atoms from the side-chain of CBD in man with production of 2"-hydroxy-tris,nor-CBD-7-oic acid. Metabolism by the epoxide-diol pathway, resulting in dihydro-diol formation from the delta-8 double bond, gave metabolites in both dog and human urine. It was concluded that CBD could be used as a probe of the mechanism of several types of biotransformation; particularly those related to carboxylic acid metabolism as intermediates of the type not usually seen with endogenous compounds were excreted in substantial concentration.
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Affiliation(s)
- D J Harvey
- University Department of Pharmacology, Oxford, U.K
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Abstract
The pharmacokinetics of cannabidiol (CBD) and six of its urinary metabolites was investigated in dogs. CBD was administered intravenously to three dogs, and urine was collected at specified time intervals over a period of 30 h. The apparent terminal half-life of CBD calculated from the slope of the sigma minus plot was significantly shorter (2 h) than the half-life of CBD calculated from plasma data (8 h), and the apparent terminal half-life of the metabolites was similar to that of the CBD calculated from plasma data, indicating that the elimination of these metabolites was formation rate limited. The time course of the metabolite excretion could be divided into two phases: the first phase contained mainly monohydroxy metabolites, and the second phase contained mainly metabolites with a carboxylic acid moiety in their side-chain.
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Affiliation(s)
- E Samara
- Department of Pharmacy, School of Pharmacy, Hebrew University of Jerusalem, Israel
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Samara E, Bialer M, Harvey DJ. Identification of urinary metabolites of cannabidiol in the dog. Drug Metab Dispos 1990; 18:571-9. [PMID: 1981704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Three dogs were treated with cannabidiol (CBD) and urine samples were collected periodically to 30 hr. Metabolites were extracted with ethyl acetate before and after hydrolysis with beta-glucuronidase, and examined by GC/MS,. Thirty-seven metabolites were identified and another nine partially characterized. Twenty-one of the identified metabolites have not been reported before for this drug. The major oxidative metabolic routes were 6-hydroxylation, both alpha and beta, and beta-oxidation. At 10 hr the major metabolites of this type were 6-hydroxy-4'',5''-bis,nor-CBD-3''-oic acid and 6-oxo-4'',5''-bis,nor-CBD-3''-oic acid, whereas at 22 hr, further beta-oxidation had occurred to give 6-hydroxy-2'',3'',4'',5''-tetrakis,nor-CBD-1"pr-oic acid as the major metabolite. Other metabolic routes were carboxylic acid formation at C-7 accompanied by hydroxylation in the side chain, and dihydroxylation of the C-8,9 double bond. Three compounds, 4''-hydroxy-CBD, 5''hydroxy-CBD, and 6-oxo-CBD were found at early times as glucose conjugates in concentrations that exceeded those of the other metabolites. The unconjugated forms of these metabolites were not found and none of the identified oxidized metabolites were found as glucosides. Only 4'',6-dihydroxy-CBD was found conjugated with glucuronic acid.
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Affiliation(s)
- E Samara
- Department of Pharmacology, Oxford University, UK
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Samara E, Brown NK, Harvey DJ. Microsomal metabolism of the 1",1"-dimethylheptyl analogue of cannabidiol: relative percentage of monohydroxy metabolites in four species. Drug Metab Dispos 1990; 18:548-9. [PMID: 1976083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- E Samara
- Department of Pharmacy, Hebrew University of Jerusalem
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Abstract
1. Metabolism of the 1",1"-dimethylheptyl analogue of cannabidiol (DMH-CBD) was studied using an isolated perfused rat liver preparation and in rat and dog urine. 2. Metabolites were identified using g.l.c.-mass spectrometry of the trimethylsilyl (TMS), methyl ester/TMS and [2H9]TMS derivatives. 3. In contrast with the metabolism of cannabidiol, the dimethylheptyl analogue gave low concentrations of metabolites in all media examined. 4. Four metabolites were found in the perfusion fluid. Two were identified as 6- and 7-hydroxy-DMH-CBD and the other two were found to be hydroxylated in the dimethylheptyl chain but at undetermined positions. 5. Five metabolites were identified in dog urine; these were the 6- and 7-mono-hydroxy and 6,7-dihydroxy derivatives of acids formed by one stage of beta-oxidation of the dimethylheptyl chain, and the 6- and 7-hydroxy derivatives of corresponding acids formed by loss of three carbon atoms from the chain. 6. Metabolic routes were very similar to those found earlier for cannabidiol.
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Affiliation(s)
- E Samara
- Department of Pharmacy, Hebrew University of Jerusalem, Israel
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Abstract
1. Three dogs were treated i.v. with cannabidiol (CBD) and urine collected at intervals to 30 h. 2. Metabolites were extracted, converted into trimethylsilyl (TMS) derivatives and examined by g.l.c.-mass spectrometry. 3. The major metabolites excreted at early times were identified as the phenol glucosides of 4"-hydroxy-CBD, 5"-hydroxy-CBD and 6-oxo-CBD. 4. These three oxidized metabolites were not found unconjugated, and none of the free oxidized metabolites in urine were found conjugated with glucose. 5. The conjugates were hydrolysed by beta-glucuronidase Type HP-2 from Helix pomatia and acid phosphatase but not by beta-glucuronidase Type VII from E. coli. Differential reactivity towards alpha- and beta-glucosidase indicated that they possessed the beta-configuration.
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Affiliation(s)
- E Samara
- Department of Pharmacy, Hebrew University of Jerusalem, Israel
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Samara E, Bialer M. Pharmacokinetics of the dimethylheptyl homolog of cannabidiol in dogs. Drug Metab Dispos 1988; 16:875-9. [PMID: 2907468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cannabidiol (CBD) is one of the major nonpsychoactive cannabinoids produced by Cannabis sativa L. Recent studies have shown that a dimethylheptyl homolog (DMH) of CBD is more active as an anticonvulsant than is the naturally occurring CBD. In considering DMH as a potential antiepileptic agent, its pharmacokinetics was studied in dogs (N = 8) after both iv (20 mg) and oral (80 mg) administration. After iv administration, DMH was rapidly distributed. DMH has a mean terminal half-life of 2 hr, its plasma levels decline in a biphasic fashion, and its total body clearance is 8.3 liters/hr. This clearance value, after being normalized to blood clearance by the use of mathematical equations, was less than one half of the value of the hepatic blood flow and its extraction ratio (E) by the liver is 0.39, DMH was observed to have a mean volume of distribution of 10 liters (or 0.5 liters/kg). In four of the eight dogs studied, DMH could not be detected in the plasma after oral administration. In the other four, the oral bioavailability was 3, 21, 39, and 43%, respectively. After oral administration, DMH has a low and variable bioavailability, due to a liver first-pass effect and incomplete absorption from the gastrointestinal tract. In comparison with CBD, DMH has a shorter half-life and lower clearance and volume of distribution values, and its liver extraction ratio is about one half that of CBD.
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Affiliation(s)
- E Samara
- Department of Pharmacy, School of Pharmacy, Hebrew University of Jerusalem, Israel
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Raz I, Hussein Z, Samara E, Ben-David J. Comparative pharmacokinetic analysis of a novel sustained-release dosage form of diclofenac sodium in healthy subjects. Int J Clin Pharmacol Ther Toxicol 1988; 26:246-8. [PMID: 3410601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The pharmacokinetics and relative bioavailability of diclofenac sodium from a new sustained-release formulation (Effekton-100) and from a standard sustained-release formulation (Voltaren-Retard) were compared in 11 healthy adult male volunteers. After a single oral dose of 100 mg Effekton-100, a mean maximal plasma concentration (Cmax) of 497 +/- 120 ng/ml was obtained after 7.4 h (tmax). After an identical dose of Voltaren-Retard, a peak plasma concentration of 654 +/- 329 ng/ml was obtained after 6.4 h. Plasma levels of diclofenac were determined by a new HPLC assay which was developed as part of this study and makes possible monitoring plasma levels of diclofenac for 24 h after a single dose. The mean bioavailability of diclofenac from Effekton-100 was 0.97 +/- 0.28 relative to that of Voltaren-Retard. As the rate and the extent of absorption of diclofenac sodium was not significantly different after the administration of the two investigated formulations, it can be concluded that Effekton-100 is bioequivalent to Voltaren-Retard.
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Affiliation(s)
- I Raz
- Department of Internal Medicine B, Hadassah Medical Center, Jerusalem, Israel
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Samara E, Bialer M, Mechoulam R. Pharmacokinetics of cannabidiol in dogs. Drug Metab Dispos 1988; 16:469-72. [PMID: 2900742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cannabidiol (CBD) is one of the major nonpsychoactive cannabinoids produced by Cannabis sativa L. Recent studies have shown that CBD has a high protective index, comparable to that of phenobarbital and phenytoin. Because CBD has been reported to possess both anticonvulsant and antiepileptic activity, its pharmacokinetics were studied in dogs after the administration of two iv doses (45 and 90 mg) and one oral dose (180 mg) to dogs. After iv administration, CBD was rapidly distributed, followed by a prolonged elimination. It has a terminal half-life of 9 hr. CBD plasma levels declined in a triphasic fashion. The total body clearance of CBD was 17 liters/hr (after the 45-mg dose) and 16 liters/hr (after the 90-mg dose). This clearance value, after its normalization to blood clearance using mathematical equations, approaches the value of the hepatic blood flow; the extraction ratio in the liver is 0.74. CBD was observed to have a large volume of distribution, approximately 100 liters. In the dose range of 45 to 90 mg, the increase in the AUC was proportional to the dose, a fact that indicates that the pharmacokinetic profile of CBD in this dose range was not dose dependent. In three of the six dogs studied, CBD could not be detected in the plasma after oral administration. In the other three, the oral bioavailability ranged from 13 to 19%. The results of this study show that CBD is barely absorbed after oral administration to dogs. This low bioavailability may be due to a first pass effect.
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Affiliation(s)
- E Samara
- Department of Pharmacy, School of Pharmacy, Hebrew University, Jerusalem, Israel
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Raz I, Ben-David J, Hussein Z, Samara E. Comparative pharmacokinetic analysis of novel sustained-release dosage forms of pentoxifylline in healthy subjects. Int J Clin Pharmacol Ther Toxicol 1988; 26:206-8. [PMID: 3403100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The pharmacokinetics and relative bioavailability of pentoxifylline, from a new sustained-release formulation (Oxopurin) and from a standard sustained-release formulation (Trental-400), were compared in 8 healthy adult male volunteers. After a single oral dose of 400 mg Oxopurin, a mean maximal plasma concentration (Cmax) of 164 +/- 62 micrograms/l was obtained after 2.2 h (tmax). After an identical dose of Trental-400, a peak plasma concentration of 123 +/- 33 micrograms/l was obtained after 2.4 h. Plasma levels of pentoxifylline were determined by a new HPLC assay which was developed as part of this study and makes possible monitoring plasma levels of pentoxifylline for 14 h after a single dose. The mean relative bioavailability of pentoxifylline from Oxopurin was 1.30 +/- 0.19 relative to that of Trental-400. As the rate and the extent of absorption of pentoxifylline was not significantly different after the administration of the two investigated formulations, it can be concluded that Oxopurin is bioequivalent to Trental-400.
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Affiliation(s)
- I Raz
- Department of Internal Medicine B, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
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Samara E, Bialer M. Rapid high-performance liquid chromatographic assay with pharmacokinetic applications for monitoring cannabidiol in plasma. J Chromatogr 1987; 416:370-4. [PMID: 3611268 DOI: 10.1016/0378-4347(87)80522-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Corneli O, Samara E, Corneli JC. [Gynecologic hemoperitoneum. Personal experience in a gynecology and obstetrics clinic]. Prensa Med Argent 1970; 57:309-10. [PMID: 5452868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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