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Kim E, Kim HC, Van Reet J, Böhlke M, Yoo SS, Lee W. Transcranial focused ultrasound-mediated unbinding of phenytoin from plasma proteins for suppression of chronic temporal lobe epilepsy in a rodent model. Sci Rep 2023; 13:4128. [PMID: 36914775 PMCID: PMC10011522 DOI: 10.1038/s41598-023-31383-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
The efficacy of many anti-epileptic drugs, including phenytoin (PHT), is reduced by plasma protein binding (PPB) that sequesters therapeutically active drug molecules within the bloodstream. An increase in systemic dose elevates the risk of drug side effects, which demands an alternative technique to increase the unbound concentration of PHT in a region-specific manner. We present a low-intensity focused ultrasound (FUS) technique that locally enhances the efficacy of PHT by transiently disrupting its binding to albumin. We first identified the acoustic parameters that yielded the highest PHT unbinding from albumin among evaluated parameter sets using equilibrium dialysis. Then, rats with chronic mesial temporal lobe epilepsy (mTLE) received four sessions of PHT injection, each followed by 30 min of FUS delivered to the ictal region, across 2 weeks. Two additional groups of mTLE rats underwent the same procedure, but without receiving PHT or FUS. Assessment of electrographic seizure activities revealed that FUS accompanying administration of PHT effectively reduced the number and mean duration of ictal events compared to other conditions, without damaging brain tissue or the blood-brain barrier. Our results demonstrated that the FUS technique enhanced the anti-epileptic efficacy of PHT in a chronic mTLE rodent model by region-specific PPB disruption.
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Affiliation(s)
- Evgenii Kim
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Hyun-Chul Kim
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
- Department of Artificial Intelligence, Kyungpook National University, Daegu, South Korea
| | - Jared Van Reet
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Mark Böhlke
- Massachusetts College of Pharmacy and Health Sciences University, Boston, MA, USA
| | - Seung-Schik Yoo
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Wonhye Lee
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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Yousfan A, Rubio N, Al-Ali M, Nattouf AH, Kafa H. Intranasal delivery of phenytoin-loaded nanoparticles to the brain suppresses pentylenetetrazol-induced generalized tonic clonic seizures in an epilepsy mouse model. Biomater Sci 2021; 9:7547-7564. [PMID: 34652351 DOI: 10.1039/d1bm01251g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work we describe the preparation and characterization of lecithin-chitosan nanoparticles (L10Ci+), and investigate their ability to deliver the anti-epileptic drug phenytoin (PHT) to mouse brain following intranasal (IN) administration. L10Ci+ were retained in the nasal cavity compared to PHT in PEG200 solution (PHT/PEG), which suffered immediate nasal drainage. PHT was detected in the brain after 5 min of IN administration reaching a maximum of 11.84 ± 2.31 %ID g-1 after 48 hours. L10Ci+ were associated with a higher brain/plasma ratio (Cb/p) compared to the experimental control comprising free PHT injected via the intraperitoneal route (PHT-IP) across all tested time points. Additionally, L10Ci+ led to lower PHT accumulation in the liver and spleen compared to PHT-IP, which is vital for lowering the systemic side effects of PHT. The relatively high drug targeting efficiency (DTE%) of 315.46% and the drug targeting percentage (DTP%) of 68.29%, combined with the increasing anterior-to-posterior gradient of PHT in the brain confirmed the direct nose-to-brain transport of PHT from L10Ci+. Electroencephalogram (EEG) analysis was used to monitor seizure progression. L10Ci+ resulted in a complete seizure suppression after 4 hours of administration, and this inhibition persisted even with an 8-fold reduction of the encapsulated dose compared to the required PHT-IP dose to achieve a similar inhibitory effect due to systemic loss. The presented findings confirm the possibility of using L10Ci+ as a non-invasive delivery system of PHT for the management of epilepsy using reduced doses of PHT.
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Affiliation(s)
- Amal Yousfan
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Damascus University, Syria
| | - Noelia Rubio
- Department of Chemistry and Materials, Imperial College London, SW7 2AZ, UK
| | - Mohammad Al-Ali
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria.
| | - Abdul Hakim Nattouf
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Damascus University, Syria
| | - Houmam Kafa
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria.
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Pires PC, Santos LT, Rodrigues M, Alves G, Santos AO. Intranasal fosphenytoin: The promise of phosphate esters in nose-to-brain delivery of poorly soluble drugs. Int J Pharm 2020; 592:120040. [PMID: 33157214 DOI: 10.1016/j.ijpharm.2020.120040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 10/23/2022]
Abstract
Intranasal administration could increase both safety and efficacy of drugs acting on the central nervous system, but low solubility severely limits administration through this route. Phenytoin's prodrug, fosphenytoin, is hydrophilic and freely soluble in water, but less permeable since it is dianionic. We aimed to assess whether this phosphoester prodrug could be a suitable alternative to phenytoin in intranasal delivery. Secondly, we aimed to compare simple formulation strategies in fosphenytoin delivery. Fosphenytoin formulations containing thermosensitive and/or mucoadhesive (hydroxypropyl methylcellulose, HPMC) polymers were developed, guided by viscosity, gelling temperatures, osmolality, and in vitro drug release tests. Then, a pharmacokinetic study was performed, comparing an intravenous fosphenytoin solution, an intranasal fosphenytoin solution, and intranasal fosphenytoin mucoadhesive formulations with or without albumin. Formulations containing HPMC allowed high drug strengths, and had a relatively fast release profile, which was not changed by albumin. Intranasal administration of a formulation with HPMC and albumin prolonged drug concentration over time and led to complete or even increased absolute bioavailability. Moreover, phenytoin's blood levels did not reach the high peak obtained with intravenous administration. In conclusion, the use of phosphate ester prodrugs could be an efficient and safe strategy to increase the intranasal bioavailability of poorly soluble drugs.
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Affiliation(s)
- Patrícia C Pires
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Liliana T Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Márcio Rodrigues
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Research Unit for Inland Development (UDI-IPG), Polytechnic Institute of Guarda, 6300-559 Guarda, Portugal.
| | - Gilberto Alves
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Adriana O Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
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Glauser T, Shinnar S, Gloss D, Alldredge B, Arya R, Bainbridge J, Bare M, Bleck T, Dodson WE, Garrity L, Jagoda A, Lowenstein D, Pellock J, Riviello J, Sloan E, Treiman DM. Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults: Report of the Guideline Committee of the American Epilepsy Society. Epilepsy Curr 2016; 16:48-61. [PMID: 26900382 PMCID: PMC4749120 DOI: 10.5698/1535-7597-16.1.48] [Citation(s) in RCA: 673] [Impact Index Per Article: 84.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
CONTEXT The optimal pharmacologic treatment for early convulsive status epilepticus is unclear. OBJECTIVE To analyze efficacy, tolerability and safety data for anticonvulsant treatment of children and adults with convulsive status epilepticus and use this analysis to develop an evidence-based treatment algorithm. DATA SOURCES Structured literature review using MEDLINE, Embase, Current Contents, and Cochrane library supplemented with article reference lists. STUDY SELECTION Randomized controlled trials of anticonvulsant treatment for seizures lasting longer than 5 minutes. DATA EXTRACTION Individual studies were rated using predefined criteria and these results were used to form recommendations, conclusions, and an evidence-based treatment algorithm. RESULTS A total of 38 randomized controlled trials were identified, rated and contributed to the assessment. Only four trials were considered to have class I evidence of efficacy. Two studies were rated as class II and the remaining 32 were judged to have class III evidence. In adults with convulsive status epilepticus, intramuscular midazolam, intravenous lorazepam, intravenous diazepam and intravenous phenobarbital are established as efficacious as initial therapy (Level A). Intramuscular midazolam has superior effectiveness compared to intravenous lorazepam in adults with convulsive status epilepticus without established intravenous access (Level A). In children, intravenous lorazepam and intravenous diazepam are established as efficacious at stopping seizures lasting at least 5 minutes (Level A) while rectal diazepam, intramuscular midazolam, intranasal midazolam, and buccal midazolam are probably effective (Level B). No significant difference in effectiveness has been demonstrated between intravenous lorazepam and intravenous diazepam in adults or children with convulsive status epilepticus (Level A). Respiratory and cardiac symptoms are the most commonly encountered treatment-emergent adverse events associated with intravenous anticonvulsant drug administration in adults with convulsive status epilepticus (Level A). The rate of respiratory depression in patients with convulsive status epilepticus treated with benzodiazepines is lower than in patients with convulsive status epilepticus treated with placebo indicating that respiratory problems are an important consequence of untreated convulsive status epilepticus (Level A). When both are available, fosphenytoin is preferred over phenytoin based on tolerability but phenytoin is an acceptable alternative (Level A). In adults, compared to the first therapy, the second therapy is less effective while the third therapy is substantially less effective (Level A). In children, the second therapy appears less effective and there are no data about third therapy efficacy (Level C). The evidence was synthesized into a treatment algorithm. CONCLUSIONS Despite the paucity of well-designed randomized controlled trials, practical conclusions and an integrated treatment algorithm for the treatment of convulsive status epilepticus across the age spectrum (infants through adults) can be constructed. Multicenter, multinational efforts are needed to design, conduct and analyze additional randomized controlled trials that can answer the many outstanding clinically relevant questions identified in this guideline.
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Affiliation(s)
- Tracy Glauser
- Division of Neurology, Comprehensive Epilepsy Center, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH
| | - Shlomo Shinnar
- Departments of Neurology, Pediatrics, and Epidemiology and Population Health, and the Comprehensive Epilepsy Management Center, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY
| | | | - Brian Alldredge
- School of Pharmacy, University of California, San Francisco, CA
| | - Ravindra Arya
- Division of Neurology, Comprehensive Epilepsy Center, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH
| | - Jacquelyn Bainbridge
- Department of Clinical Pharmacy, University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO
| | - Mary Bare
- Division of Neurology, Comprehensive Epilepsy Center, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH
| | - Thomas Bleck
- Departments of Neurological Sciences, Neurosurgery, Medicine, and Anesthesiology, Rush University Medical Center, Chicago, IL
| | - W. Edwin Dodson
- Departments of Neurology and Pediatrics, Washington University School of Medicine, St. Louis, MO
| | - Lisa Garrity
- Division of Pharmacy, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Andy Jagoda
- Department of Emergency Medicine, Mount Sinai Hospital, Mount Sinai School of Medicine, New York, NY
| | - Daniel Lowenstein
- Department of Neurology, University of California, San Francisco, CA
| | - John Pellock
- Division of Pediatric Neurology, Virginia Commonwealth University, Richmond, VA
| | | | - Edward Sloan
- Department of Emergency Medicine, University of Illinois at Chicago, Chicago, IL
| | - David M. Treiman
- Division of Neurology, Barrow Neurological Institute, Phoenix, AZ
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Rosenow F, Knake S. Recent and future advances in the treatment of status epilepticus. Ther Adv Neurol Disord 2011; 1:33-42. [PMID: 21180563 DOI: 10.1177/1756285608094263] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Status epilepticus (SE) is one of the most frequent neurological emergencies with an incidence of 20/100,000 per year and a mortality between 3% and 40% depending on etiology, age, SE type and duration. Generalized convulsive forms of SE (GTCSE), in particular, require aggressive treatment. Presently, only 55-80% of cases of GTCSE are controlled by initial therapy. Therefore, there is a need for new options for the treatment of SE. Here we review the current standard treatment including recent advances and provide a summary of preclinical and clinical data regarding treatment options which may become available in the near future. The initial treatment of SE usually consists of a benzodiazepine (preferably lorazepam 0.1 mg/kg) followed by phenytoin or fosphenytoin or valproic acid (where approved for SE therapy). With intravenous formulations of levetiracetam, available since 2006, and lacosamide, which is expected for autumn of 2008, new treatment options have become available, that should be evaluated in prospective controlled trials. If SE remains refractory, the induction of general anaesthesia using propofol, midazolam, thiopental, or pentobarbital is warranted in GTCSE.
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Affiliation(s)
- Felix Rosenow
- Interdisciplinary Epilepsy Center Marburg Department of Neurology Philipps-University Marburg, Rudolf-Bultmann-Str. 8, 35033 Marburg, Germany
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Rossetti AO. Treatment Options in the Management of Status Epilepticus. Curr Treat Options Neurol 2010; 12:100-12. [DOI: 10.1007/s11940-010-0060-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Knake S, Hamer HM, Rosenow F. Status epilepticus: a critical review. Epilepsy Behav 2009; 15:10-4. [PMID: 19236943 DOI: 10.1016/j.yebeh.2009.02.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
Abstract
Status epilepticus (SE) is a major neurological emergency with an incidence of about 20/100,000 and a mortality between 3 and 40% depending on etiology, age, status type, and status duration. Generalized tonic-clonic SE, in particular, requires immediate, aggressive, and effective treatment to stop seizure activity, and to prevent neuronal damage and systemic complications and death. Benzodiazepines and phenytoin/fosphenytoin are traditionally used as first-line drugs and are effective in about 60% of all episodes. However, a notable portion of patients remain in SE. For those, narcotics and induction of general anesthesia are used as second-line treatment. Therefore, there is a need for more effective first-line treatment options. Recently, valproic acid was approved for the treatment of status epilepticus in some European countries, and two of the newer antiepileptic drugs have become available for intravenous use: Levetiracetam (LEV) and lacosamide (LCM) should be evaluated in prospective controlled trials as possible treatment options. Standardized protocols for the management of SE are useful to improve immediate care.
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Affiliation(s)
- Susanne Knake
- Interdisciplinary Epilepsy Center Marburg, Department of Neurology, Philipps University Marburg, Rudolf-Bultmann-Strasse 8, 35033 Marburg, Germany.
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8
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Łuszczki JJ. Third-generation antiepileptic drugs: mechanisms of action, pharmacokinetics and interactions. Pharmacol Rep 2009; 61:197-216. [DOI: 10.1016/s1734-1140(09)70024-6] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Revised: 02/13/2009] [Indexed: 01/23/2023]
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10
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Wang X, Patsalos PN. A comparison of central brain (cerebrospinal and extracellular fluids) and peripheral blood kinetics of phenytoin after intravenous phenytoin and fosphenytoin. Seizure 2003; 12:330-6. [PMID: 12915078 DOI: 10.1016/s1059-1311(03)00099-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Phenytoin (PHT) is a first-line drug in the treatment of status epilepticus. However, the parenteral PHT formulation is associated with administration difficulties and therefore fosphenytoin (FosPHT), a PHT pro-drug, has been developed. As the peripheral (blood) and central (cerebrospinal fluid [CSF] and brain extracellular fluid [ECF]) kinetic inter-relationship of PHT after i.v. FosPHT administration is unknown we sought to ascertain the relationship and to compare it to that of i.v. PHT. A freely behaving rat model, which allows for the concurrent and temporal sampling of blood (jugular vein), CSF (cisterna magna) and brain ECF (frontal cortex and hippocampus), was used. PHT and FosPHT were administered by i.v. infusion and blood, CSF and microdialysate samples collected at timed intervals up to 6 hours. The pharmacokinetic parameters in plasma of PHT after PHT and FosPHT (30 and 60 mg/kg) administration were indistinguishable. The PHT plasma free fraction (free/total concentration ratio) was 0.25-0.31 and 0.26-0.31 for PHT and FosPHT, respectively. Mean PHT Tmax values for CSF were 9-13 minutes. The equivalent values in the frontal cortex and hippocampal ECF were 29-34 minutes. Cmax values increased dose-dependently and were independent of whether PHT or FosPHT was administered. Furthermore the kinetic profiles of PHT for the frontal cortex and hippocampus were indistinguishable suggesting that PHT distribution in the brain is not brain region specific. Thus, overall, the central and peripheral kinetics of PHT are indistinguishable after PHT and FosPHT.
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Affiliation(s)
- Xiaolan Wang
- Pharmacology and Therapeutics Unit, Department of Clinical and Experimental Epilepsy, Institute of Neurology, Queen Square, London, UK
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11
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Lawn ND, Wijdicks EFM. Progress in clinical neurosciences: Status epilepticus: a critical review of management options. Can J Neurol Sci 2002; 29:206-15. [PMID: 12195609 DOI: 10.1017/s0317167100001967] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Although generalized tonic-clonic status epilepticus (SE) is frequently seen, an evidence-based approach to management is limited by a lack of randomized clinical studies. Clinical practice, therefore, relies on a combination of expert recommendations, local hospital guidelines and dogma based on individual preference and past successes. This review explores selected and controversial aspects of SE in adults and provides a critical appraisal of currently recommended management strategies.
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Affiliation(s)
- Nicholas D Lawn
- Department of Neurology, Neurological-Neurosurgical ICU, Mayo Clinic, Rochester, Minnesota, USA
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12
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Muchohi SN, Kokwaro GO, Maitho TE, Munenge RW, Watkins WM, Edwards G. Pharmacokinetics of phenytoin following intravenous and intramuscular administration of fosphenytoin and phenytoin sodium in the rabbit. Eur J Drug Metab Pharmacokinet 2002; 27:83-9. [PMID: 12064376 DOI: 10.1007/bf03190421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The purpose of this study was to evaluate and compare plasma phenytoin concentration versus time profiles following intravenous (i.v.) and intramuscular (i.m.) administration of fosphenytoin sodium with those obtained following administration of standard phenytoin sodium injection in the rabbit. Twenty-four adult New Zealand White rabbits (2.1 +/- 0.4 kg) were anaesthetized with sodium pentobarbitone (30 mg/kg) followed by i.v. or i.m. administration of a single 10 mg/kg phenytoin sodium or fosphenytoin sodium equivalents. Blood samples (1.5 ml) were obtained from a femoral artery cannula predose and at 1, 3, 5, 7, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240 and 300 min after drug administration. Plasma was separated by centrifugation (1000 g; 5 min) and fosphenytoin, total and free plasma phenytoin concentrations were measured using high performance liquid chromatography (HPLC). Following i.v. administration of fosphenytoin sodium plasma phenytoin concentrations were similar to those obtained following i.v. administration of an equivalent dose of phenytoin sodium. Mean peak plasma phenytoin concentrations (Cmax) was 158% higher (P = 0.0277) following i.m. administration of fosphenytoin sodium compared to i.m. administration of phenytoin sodium. The mean area under the plasma total and free phenytoin concentration-time curve from time zero to 120 min (AUC(0-120)) following i.m. administration was also significantly higher (P = 0.0277) in fosphenytoin treated rabbits compared to the phenytoin group. However, there was no significant difference in AUC(0-180) between fosphenytoin and phenytoin-treated rabbits following i.v. administration. There was also no significant difference in the mean times to achieve peak plasma phenytoin concentrations (Tmax) between fosphenytoin and phenytoin-treated rabbits following i.m. administration. Mean plasma albumin concentrations were comparable in both groups of animals. Fosphenytoin was rapidly converted to phenytoin both after i.v. and i.m. administration, with plasma fosphenytoin concentrations declining rapidly to undetectable levels within 10 min following administration via either route. These results confirm the rapid and complete hydrolysis of fosphenytoin to phenytoin in vivo, and the potential of the i.m. route for administration of fosphenytoin delivering phenytoin in clinical settings where i.v. administration may not be feasible.
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Affiliation(s)
- S N Muchohi
- Kenya Medical Research Institute-Wellcome Trust Collaborative Research Programme, Nairobi
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13
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Mizukami Y, Yamada S, Kokudo N, Takashima M, Yokoyama T. Dietary iron reduces the anti-convulsion activity of phenytoin in electroconvulsion via inhibition of brain penetration. Brain Res 2001; 915:112-7. [PMID: 11578628 DOI: 10.1016/s0006-8993(01)02836-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We determined the anti-convulsion activity of phenytoin (PHT) using the maximum electron shock method in mice fed diets containing various concentrations of iron for 18 weeks. Dietary iron reduces the anti-convulsion activity of PHT in a dose-dependent manner (0-6100 ppm). High concentrations of PHT are detected in the plasma of mice fed a high iron diet compared with those fed normal and low iron diets, in contrast to the pharmacological effect. However, the concentration of PHT in the brains of mice fed high amounts of dietary iron decreased significantly 3 h after treatment with PHT, consistent with the anti-convulsion effect of PHT. The relationship between brain and plasma-unbound concentrations of PHT indicates that the penetration of PHT into brain is significantly inhibited by dietary iron.
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Affiliation(s)
- Y Mizukami
- Department of Hospital Pharmacy, Faculty of Pharmaceutical Sciences, Kyoto Pharmaceutical University, Kyoto, Japan.
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