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Long-term Survival, Tolerability, and Safety of First-Line Bevacizumab and FOLFIRI in Combination With Ginsenoside-Modified Nanostructured Lipid Carrier Containing Curcumin in Patients With Unresectable Metastatic Colorectal Cancer. Integr Cancer Ther 2022; 21:15347354221105498. [PMID: 35695002 PMCID: PMC9202259 DOI: 10.1177/15347354221105498] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Colorectal cancer is the third most common malignant disease and the second leading cause of death worldwide. Previous studies showed improved bioavailability and cytotoxicity of ginsenoside-modified nanostructured lipid carrier containing curcumin (G-NLC) in human colon cancer cell lines. This study aimed to evaluate the safety and tolerability with long-term survival rates in patients with colorectal cancer with unresectable metastases after treatment with first-line bevacizumab/FOLFIRI (folinic acid, bolus/continuous fluorouracil, and irinotecan) in combination with a dietary supplement of G-NLC. METHODS This study was a prospective, observational, single-group analysis. The enrolled patients had colorectal cancer with unresectable metastases and were administered bevacizumab and FOLFIRI in combination with daily oral G-NLC as first-line treatment. Overall survival, progression-free survival, tumor response, and adverse events were evaluated. RESULTS A total of 44 patients were enrolled between 2015 and 2019. The median age was 65 (range 45-81) years and the sex ratio was 31:13 (male:female). The primary tumor locations were the colon (31 patients) and rectum (13 patients). The metastatic sites included, liver only (n = 20), lung only (n = 6), both liver and lung (n = 12), and others (n = 6). The median duration of curcumin supply was 7.9 (range 0.9-16.6) months. The most common grade 3 or higher adverse events were neutropenia (n = 15, 34.1%), followed by nausea (n = 4, 9.1%) and vomiting (n = 4, 9.1%). Within the median follow-up period of 22.8 months, the median overall survival was 30.7 months, and the median progression-free survival was 12.8 months. None of the patients achieved complete response (CR); however, 9 patients showed partial response (PR), and 3 patients underwent conversion surgery. CONCLUSIONS Bevacizumab/FOLFIRI with G-NLC as first-line chemotherapy in patients with colorectal cancer with unresectable metastases presented comparable long-term survival outcomes with acceptable toxicity outcomes. Additional randomized controlled studies are needed to establish definitive conclusions regarding this new regimen for metastatic colorectal cancer.
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In Vitro Cytotoxicity and Bioavailability of Ginsenoside-Modified Nanostructured Lipid Carrier Containing Curcumin. AAPS PharmSciTech 2019; 20:88. [PMID: 30675630 DOI: 10.1208/s12249-019-1295-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/27/2018] [Indexed: 12/13/2022] Open
Abstract
Our aim was to investigate the cellular uptake, in vitro cytotoxicity and bioavailability of ginsenoside-modified nanostructured lipid carrier loaded with curcumin (G-NLC). The formulation was prepared by melt emulsification technique, in which water was added to the melted lipids and homogenized to give a uniform suspension of NLC (without ginsenoside) and G-NLC. Cellular uptake of curcumin in two colon cancer cell lines (HCT116 and HT29) was increased when administered using both NLC and G-NLC compared to control (curcumin dissolved into DMSO) as measured by fluorescence microscopy. Ginsenoside modification resulted in 2.0-fold and 1.4-fold increases in fluorescence intensity in HCT116 and HT29 cell lines, respectively, compared to plain NLC. In vitro cytotoxicity (assessed by MTT assay) had a dose-dependent relationship with curcumin concentration for both NLC and G-NLC. Although G-NLC was taken up more readily in HCT116 cells, ginsenoside modification did not produce a significant increase in cytotoxic effect; a significant increase was observed in HT29 cells. Oral administration of G-NLC in ten colon cancer patients produced an appreciable plasma level of unbound curcumin (2.9 ng/mL). In conclusion, introduction of ginsenoside into NLC enhanced the cellular uptake and cytotoxicity of curcumin as well as its oral bioavailability, and this strategy can be used to improve clinical outcomes in the treatment of colon cancer with similar genotype to HT29.
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Quercetin-Loaded Solid Lipid Nanoparticle Dispersion with Improved Physicochemical Properties and Cellular Uptake. AAPS PharmSciTech 2017; 18:875-883. [PMID: 27368922 DOI: 10.1208/s12249-016-0573-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/15/2016] [Indexed: 12/22/2022] Open
Abstract
The objective of this study was to formulate and characterize properties of solid lipid nanoparticle (SLN) dispersion containing quercetin. SLN was prepared by ultrasonication method using tripalmitin and lecithin as lipid core and then the surface was coated with chitosan. Entrapment efficiency was greater than 99%, and mean particle size of SLN was 110.7 ± 1.97 nm with significant increase in the coated SLN (c-SLN). Zeta potential was proportionally increased and reached plateau at 5% of chitosan coating with respect to tripalmitin. Differential scanning calorimetry showed disappearance of endothermic peak of quercetin in SLNs, indicating conversion of crystalline state to amorphous state. FTIR study of SLNs showed no change in the spectrum of quercetin, which indicates that the lipid and chitosan were not incompatible with quercetin. When coating amount was greater than 2.5% of tripalmitin, particle size and zeta potential were very stable even at 40°C up to 90 days. All SLN dispersions showed significantly faster release profile compared to pure quercetin powder. At pH 7.0, the release rate was increased in proportion to the coating amount. Interestingly, at pH 3.0, chitosan coating of 5.0% or greater decreased the rate. Cellular uptake of quercetin was performed using Caco-2 cells and showed that all SLN dispersions were significantly better than quercetin dispersed in distilled water. However, cellular uptake of quercetin from c-SLN was significantly lower than that from uncoated SLN.
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Abstract
Objective: To evaluate available literature characterizing the pharmacology, pharmacokinetics, drug interactions, efficacy, and safety of exenatide in patients with type 2 diabetes. Data Sources: A PubMed database search (1966–May 2006) was conducted, using exenatide as the search term. The manufacturer's prescribing information was also used. Study Selection and Data Extraction: English-language articles were selected and data were extracted with a focus on clinical outcomes associated with the treatment of patients with type 2 diabetes. Data Synthesis: Exenatide exerts a glucoregulatory effect by various mechanisms including secretion of glucose-dependent insulin, suppression of inappropriately high glucagon levels in patients with type 2 diabetes, delayed gastric emptying, and reduction of food intake. In placebo-controlled clinical studies, plasma exenatide concentrations appeared to exhibit dose-proportional kinetics, reaching peak plasma levels between 2 and 3 hours after a single subcutaneous injection. Exenatide's elimination half-life ranged from 3.3 to 4.0 hours, and the time to reach maximum concentration was about 2 hours. Interactions between exenatide and agents such as digoxin and lisinopril were not considered significant. In Phase III trials, exenatide demonstrated significant reduction of hemoglobin A1c levels from baseline and compared with placebo after 30 weeks of treatment in patients unable to achieve optimal glycemic control with metformin, a sulfonylurea, or oral combination therapy (0.4–0.9%). Patients' weight decreased with exenatide (0.9–2.8 kg), but adverse gastrointestinal (GI) events were common. Exenatide combined with thiazolidonediones, D-phenylalanine derivatives, meglitinides, or alpha glucosidase inhibitors has not been studied. Conclusions: Clinical trials have demonstrated that exenatide improves glycemic control when added to sulfonylureas and metformin, and it may be an alternative to insulin glargine in patients requiring additional therapy. Hypoglycemia has been encountered in clinical trials of exenatide, especially upon initiation of therapy with sulfonylureas (not with metformin); close patient monitoring is therefore recommended. Further studies should assess the impact of exenatide on clinical outcomes such as micro- and macrovascular disease.
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Abstract
The objective of this study is to develop a topical bead formulation of tranexamic acid (TA) which can be used concomitantly with laser treatment. The bead formulation of TA (TAB) was successfully prepared by fluidized bed drying method. Physicochemical properties of the TAB were evaluated in terms of chemical stability of TA and differential scanning calorimetry. TA in the bead was stable up to six months at 25°C and existed as amorphous state. In vitro skin permeation and in vivo skin retention of TA in the beads were significantly higher compared to a commercial product. When the bead was dissolved into distilled water and applied concomitantly with laser treatment, the amount of TA retained in the skin in the in vivo study was inversely proportional to the energy levels of laser treatment, indicating absorption into subcutaneous tissue and drainage to systemic circulation. Therefore, when laser treatment is used concomitantly with TAB, energy level should be very carefully monitored to avoid possible adverse events associated with systemic side effects of TA.
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Meta-analysis of the Efficacy and Safety of Secukinumab for the Treatment of Plaque Psoriasis. Ann Pharmacother 2016; 50:341-51. [PMID: 26783352 DOI: 10.1177/1060028015626545] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND In January 2015, US FDA approved secukinumab, a human interleukin-17A (IL-17A) antagonist, for the treatment of plaque psoriasis. OBJECTIVE To provide unbiased drug information about the efficacy and safety of secukinumab for the treatment of moderate to severe plaque psoriasis by performing meta-analysis. METHODS PubMed and EMBASE database searches were conducted. Among the literatures retrieved, relevant Phase III clinical trials were analyzed. Statistical analysis of the data was performed by RevMan. RESULTS Four pivotal and three non-pivotal Phase III clinical trials were retrieved. All the trials evaluated the efficacy and safety of secukinumab for the treatment of moderate to severe plaque psoriasis with two co-primary endpoints: proportions of Psoriasis Area and Severity Index (PASI) responders and Investigator's Global Assessment (IGA) responders. The overall odd ratios for proportions of PASI responders and IGA responders in secukinumab-containing arm were 65.6 and 62.5 compared to the placebo arm, respectively. Secukinumab was superior to etanercept resulting in both of the odd ratios being 3.7 compared to the etanercept. Secukinumab was generally well tolerated during the one year trial. However, as with other monoclonal antibody medications, vulnerability of respiratory infection (especially nasopharyngitis) was reported as most common adverse event. CONCLUSIONS Meta-analysis of the seven Phase III clinical trials resulted in superiority of secukinumab over etanercept in terms of the efficacy and safety. However, long-term safety data is lacking at this time so post-marketing surveillance should be performed for any adverse events associated with the use of this new biological medication.
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Novel self-micellizing anticancer lipid nanoparticles induce cell death of colorectal cancer cells. Colloids Surf B Biointerfaces 2015; 135:793-801. [PMID: 26342325 DOI: 10.1016/j.colsurfb.2015.08.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/02/2015] [Accepted: 08/24/2015] [Indexed: 12/23/2022]
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Novel self-micellizing anticancer lipid nanoparticles induce cell death of colorectal cancer cells. Colloids Surf B Biointerfaces 2015. [PMID: 26342325 DOI: 10.1016/j.colsurfb.2015.08.039.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
In the present study, we developed a novel drug-like self-micellizing anticancer lipid (SMAL), and investigated its anticancer activity and effects on cell death pathways in human colorectal cancer (CRC) cell lines. Three self-assembled nanoparticles were prepared, namely, SMAL102 (lauramide derivative), SMAL104 (palmitamide derivative), and SMAL108 (stearamide derivative) by a thin-film hydration technique, and were characterized for physicochemical and biological parameters. SMAL102 were nanosized (160.23 ± 8.11 nm) with uniform spherical shape, while SMAL104 and SMAL108 did not form spherical shape but formed large size nanoparticles and irregular in shape. Importantly, SMAL102 showed a cytotoxic effect towards CRC cell lines (HCT116 and HT-29), and less toxicity to a normal colon fibroblast cell line (CCD-18Co). Conversely, SMAL104 and SMAL108 did not have an anti-proliferative effect on CRC cell lines. SMAL102 nanoparticles were actively taken up by CRC cell lines, localized in the cell membrane, and exhibited remarkable cytotoxicity in a concentration-dependent manner. The normal colon cell line showed significantly less cellular uptake and non-cytotoxicity as compared with the CRC cell lines. SMAL102 nanoparticles induced caspase-3, caspase-9, and PARP cleavage in HT-29 cells, indicating the induction of apoptosis; whereas LC3B was activated in HCT116 cells, indicating autophagy-induced cell death. Collectively, these results demonstrate that SMAL102 induced cell death via activation of apoptosis and autophagy in CRC cell lines. The present study could be a pioneer for further preclinical and clinical development of such compounds.
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Enhanced skin permeation of 5α-reductase inhibitors entrapped into surface-modified liquid crystalline nanoparticles. Arch Pharm Res 2014; 38:534-42. [DOI: 10.1007/s12272-014-0464-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/25/2014] [Indexed: 02/07/2023]
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Entrapment of curcumin into monoolein-based liquid crystalline nanoparticle dispersion for enhancement of stability and anticancer activity. Int J Nanomedicine 2014; 9:3119-30. [PMID: 25061290 PMCID: PMC4079637 DOI: 10.2147/ijn.s61823] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Despite the promising anticancer potential of curcumin, its therapeutic application has been limited, owing to its poor solubility, bioavailability, and chemical fragility. Therefore, various formulation approaches have been attempted to address these problems. In this study, we entrapped curcumin into monoolein (MO)-based liquid crystalline nanoparticles (LCNs) and evaluated the physicochemical properties and anticancer activity of the LCN dispersion. The results revealed that particles in the curcumin-loaded LCN dispersion were discrete and monodispersed, and that the entrapment efficiency was almost 100%. The stability of curcumin in the dispersion was surprisingly enhanced (about 75% of the curcumin survived after 45 days of storage at 40°C), and the in vitro release of curcumin was sustained (10% or less over 15 days). Fluorescence-activated cell sorting (FACS) analysis using a human colon cancer cell line (HCT116) exhibited 99.1% fluorescence gating for 5 μM curcumin-loaded LCN dispersion compared to 1.36% for the same concentration of the drug in dimethyl sulfoxide (DMSO), indicating markedly enhanced cellular uptake. Consistent with the enhanced cellular uptake of curcumin-loaded LCNs, anticancer activity and cell cycle studies demonstrated apoptosis induction when the cells were treated with the LCN dispersion; however, there was neither noticeable cell death nor significant changes in the cell cycle for the same concentration of the drug in DMSO. In conclusion, entrapping curcumin into MO-based LCNs may provide, in the future, a strategy for overcoming the hurdles associated with both the stability and cellular uptake issues of the drug in the treatment of various cancers.
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Enhanced topical delivery of finasteride using glyceryl monooleate-based liquid crystalline nanoparticles stabilized by cremophor surfactants. AAPS PharmSciTech 2014; 15:44-51. [PMID: 24222268 DOI: 10.1208/s12249-013-0034-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/10/2013] [Indexed: 11/30/2022] Open
Abstract
The aim of this study was to investigate the capability of two surfactants, Cremophor RH 40 (RH) and Cremophor EL (EL), to prepare liquid crystalline nanoparticles (LCN) and to study its influence on the topical delivery of finasteride (FNS). FNS-loaded LCN was formulated with the two surfactants and characterized for size distribution, morphology, entrapment efficiency, in vitro drug release, and skin permeation/retention. Influence of FNS-loaded LCN on the conformational changes on porcine skin was also studied using attenuated total reflectance Fourier-transform infrared spectroscopy. Transmission electron microscopical image confirmed the formation of LCN. The average particle size of formulations was in the range of 165.1-208.6 and 153.7-243.0 nm, respectively. The formulations prepared with higher surfactant concentrations showed faster release and significantly increased skin permeation. Specifically, LCN prepared with RH 2.5% presented higher permeation flux (0.100 ± 0.005 μgcm(-2)h(-1)) compared with lower concentration (0.029 ± 0.007 μgcm(-2)h(-1)). Typical spectral bands of lipid matrix of porcine skin were shifted to higher wavenumber, indicating increased degree of disorder of the lipid acyl chains which might cause fluidity increase of stratum corneum. Taken together, Cremophor surfactants exhibited a promising potential to stabilize the LCN and significantly augmented the skin permeation of FNS.
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Optimization of self-microemulsifying drug delivery system for telmisartan using Box–Behnken design and desirability function. J Pharm Pharmacol 2013; 65:1440-50. [DOI: 10.1111/jphp.12115] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 06/15/2013] [Indexed: 10/26/2022]
Abstract
Abstract
Objectives
To develop and optimize the novel self-microemulsifying drug delivery system (SMEDDS) formulation for enhanced water solubility and bioavailability of telmisartan (TMS) using the Box–Behnken design (BBD) and desirability function.
Method
TMS-SMEDDS formulation consisted of the mixture of oil (Peceol), surfactant (Labrasol), co-surfactant (Transcutol), TMS and triethanolamine. A three-level BBD was applied to explore the main effect, interaction effect and quadratic effect of three independent variables, including the amount of Peceol (X1), Labrasol (X2) and Transcutol (X3). Determined conditions were 20 < X1 < 40, 50 < X2 < 80 and 5 < X3 < 30. The response variables were droplet size (Y1), polydispersity index (Y2) and dissolution percentage of TMS after 15 min (Y3).
Key findings
The optimized conditions were 28.93, 80 and 28.08 (mg) for X1, X2 and X3, respectively, and the response variables were predicted to be 159.8 nm, 0.241 and 85.8% for Y1, Y2 and Y3, respectively. The actual values from the optimized formulation showed good agreement with predicted values. The optimized TMS-SMEDDS formulation showed faster drug dissolution rate and higher bioavailability than TMS powder.
Conclusions
Our results suggest that response surface methodology using BBD and desirability function is a promising approach to understand the effect of SMEDDS variables and to optimize the formulation.
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Design and in vitro evaluation of finasteride-loaded liquid crystalline nanoparticles for topical delivery. AAPS PharmSciTech 2013. [PMID: 23207960 DOI: 10.1208/s12249-012-9888-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In this study, liquid crystalline nanoparticles (LCN) have been proposed as new carrier for topical delivery of finasteride (FNS) in the treatment of androgenetic alopecia. To evaluate the potential of this nanocarrier, FNS-loaded LCN was prepared by ultrasonication method and characterized for size, shape, in vitro release, and skin permeation-retention properties. The particle size ranged from 153.8 to 170.2 nm with a cubical shape and exhibited controlled release profile with less than 20% of the drug released in the first 24 h. The release profile was significantly altered with addition of different additives. Formulation with lower monoolein exhibited higher skin permeation with a flux rate of 0.061±0.005 μg cm(-2) h(-1) in 24 h. The permeation however, significantly increased with glycerol, propylene glycol, and polyethylene glycol 400, while it declined for the addition of oleic acid. A similar trend was observed with skin retention study. In conclusion, FNS-loaded LCN could be advocated as a viable alternative for oral administration of the drug.
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Evaluation of the effect of tacrolimus-loaded liquid crystalline nanoparticles on psoriasis-like skin inflammation. J DERMATOL TREAT 2013; 25:22-5. [DOI: 10.3109/09546634.2012.755250] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Preparation, Characterization, and Release Study of Tacrolimus-Loaded Liquid Crystalline Nanoparticles. J DISPER SCI TECHNOL 2013. [DOI: 10.1080/01932691.2011.648462] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Solid self-nanoemulsifying drug delivery system (S-SNEDDS) containing phosphatidylcholine for enhanced bioavailability of highly lipophilic bioactive carotenoid lutein. Eur J Pharm Biopharm 2011; 79:250-7. [PMID: 21550401 DOI: 10.1016/j.ejpb.2011.04.012] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/15/2011] [Accepted: 04/21/2011] [Indexed: 11/29/2022]
Abstract
The objectives of this study was to prepare solid self-nanoemulsifying drug delivery system (S-SNEDDS) containing phosphatidylcholine (PC), an endogenous phospholipid with excellent in vivo solubilization capacity, as oil phase for the delivery of bioactive carotenoid lutein, by spray drying the SNEDDS (liquid system) containing PC using colloidal silica (Aerosil® 200 VV Pharma) as the inert solid carrier, and to evaluate the enhanced bioavailability (BA) of lutein from S-SNEDDS. The droplet size analyses revealed droplet size of less than 100 nm. The solid state characterization of S-SNEDDS by SEM, DSC, and XRPD revealed the absence of crystalline lutein in the S-SNEDDS. The bioavailability study performed in rabbits resulted in enhanced values of C(max) and AUC for S-SNEDDS. The enhancement of C(max) for S-SNEDDS was about 21-folds and 8-folds compared with lutein powder (LP) and commercial product (CP), respectively. The relative BA of S-SNEDDS compared with CP or LP was 2.74-folds or 11.79-folds, respectively. These results demonstrated excellent ability of S-SNEDDS containing PC as oil phase to enhance the BA of lutein in rabbits. Thus, S-SNEDDS containing PC as oil phase could be a useful lipid drug delivery system for enhancing the BA of lutein in vivo.
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Enhanced Oral Bioavailability of Curcumin via a Solid Lipid-Based Self-Emulsifying Drug Delivery System Using a Spray-Drying Technique. Biol Pharm Bull 2011; 34:1179-86. [DOI: 10.1248/bpb.34.1179] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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The effect of 1-furan-2-yl-3-pyridine-2-yl-propenone on pharmacokinetic parameters of theophylline. Biol Pharm Bull 2010; 29:1282-5. [PMID: 16755035 DOI: 10.1248/bpb.29.1282] [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: 11/22/2022]
Abstract
The pharmacokinetic parameters of theophylline in rats did not change significantly when the drug was intravenously administered after three consecutive days of pretreatment with 17 mg/kg, orally, of 1-furan-2-yl-3-pyridine-2-yl-propenone (FPP-3), an investigatory drug having dual inhibitory action on cyclooxygenase (COX) and 5-lipoxygenase (5-LOX). However, significant changes were found in the pharmacokinetic parameters of the drug at doses of 34 mg/kg and more of FPP-3. Results of cytochrome P450 activity test indicated that the alteration in pharmacokinetic parameters of the drug appears to be due to the inhibitory effect of FPP-3 on cytochrome P450 1A which is responsible for the metabolism of theophylline. Methoxyresorufin-O-demethylase (MROD) and ethoxyresorufin-O-deethylase (EROD) activity assays revealed that the relative activities of cytochrome P450 1A1 and 1A2 were dose-dependently reduced in the presence of 1, 5, and 10 microM FPP-3 concentrations. Taking into consideration that FPP-3 is intended to be primarily used by geriatric patients with chronic diseases and therefore may be used in long-term basis, the investigatory drug needs to be assessed thoroughly in terms of drug interaction with other commonly prescribed medications.
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Plerixafor for stem cell mobilization in patients with non-Hodgkin's lymphoma and multiple myeloma. Ann Pharmacother 2009; 44:117-26. [PMID: 20009003 DOI: 10.1345/aph.1m380] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To evaluate the literature characterizing the mechanism of action, pharmacokinetics, pharmacodynamics, and therapeutic efficacy of plerixafor for hematopoietic stem cell (HSC) mobilization for autologous transplantation in patients with non-Hodgkin's lymphoma (NHL) or multiple myeloma. DATA SOURCES A PubMed search (1966-September 2009) was conducted using the key words plerixafor and AMD3100. Manufacturer's prescribing information was also used. STUDY SELECTION AND DATA EXTRACTION English-language articles were selected and data were extracted with a focus on clinical studies of HSC mobilization in patients with NHL or multiple myeloma. DATA SYNTHESIS Plerixafor exerts its effect by reversibly blocking the ability of HSC to bind to the bone marrow matrix. When used with granulocyte colony-stimulating factor (G-CSF), plerixafor helps increase the number of HSCs in the peripheral blood, where they can be collected for use in autologous transplantation. In clinical studies, plerixafor was rapidly absorbed after subcutaneous injection, reaching a maximum plasma concentration at approximately 0.5 hours. Plerixafor is renally excreted as the parent drug, with an elimination half-life ranging from 3 to 5 hours. Plerixafor increases circulating CD34+ cells in the peripheral blood, with a peak effect about 6-9 hours after subcutaneous administration. An approximate 2- to 3-fold increase in the CD34+ cell count is seen by the first dose of plerixafor after 4 consecutive days of G-CSF treatment. In 2 Phase 3 studies in patients with NHL or multiple myeloma, addition of plerixafor to G-CSF resulted in a higher CD34+ cell collection with fewer apheresis days, but failed to show better graft durability or overall patient survival for up to 12 months of follow-up. CONCLUSIONS Clinical trials have demonstrated that the addition of plerixafor to G-CSF was beneficial for HSC mobilization to peripheral blood for collection and subsequent transplantation in patients with NHL or multiple myeloma. Further studies should assess the benefit of the additive use of plerixafor on clinical outcomes.
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Enhanced oral bioavailability of dexibuprofen by a novel solid self-emulsifying drug delivery system (SEDDS). Eur J Pharm Biopharm 2009; 72:539-45. [PMID: 19298857 DOI: 10.1016/j.ejpb.2009.03.001] [Citation(s) in RCA: 231] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/19/2009] [Accepted: 03/02/2009] [Indexed: 11/25/2022]
Abstract
The main objective of this study was to prepare a solid form of lipid-based self-emulsifying drug delivery system (SEDDS) by spray drying liquid SEDDS with an inert solid carrier Aerosil 200 to improve the oral bioavailability of poorly water-soluble drug dexibuprofen. The liquid SEDDS was a system that consisted of dexibuprofen, Labrasol, Capryol 90 and Labrafil M 1944 CS. The particle size analysis revealed no difference in the z-average particle diameter of the reconstituted emulsion between liquid and solid SEDDS. The solid SEDDS was characterized by SEM, DSC and XRD studies. In vivo results of solid SEDDS and dexibuprofen powder in rats at the dose of 10mg/kg showed that the initial plasma concentrations of drug in solid SEDDS were significantly higher than those of dexibuprofen powder (P<0.05). The solid SEDDS gave significantly higher AUC and Cmax than did dexibuprofen powder (P<0.05). In particular, the AUC of solid SEDDS was about twofold higher than that of dexibuprofen powder. Our results suggested that this solid SEDDS could be used as an effective oral solid dosage form to improve the bioavailability of poorly water-soluble drug dexibuprofen.
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Enhanced Dissolution of Ibuprofen Using Solid Dispersion with Polyethylene Glycol 20000. Drug Dev Ind Pharm 2008; 34:1013-21. [DOI: 10.1080/03639040701744095] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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First renin inhibitor, aliskiren, for the treatment of hypertension. ACTA ACUST UNITED AC 2008; 30:741-9. [PMID: 18802783 DOI: 10.1007/s11096-008-9252-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Accepted: 08/31/2008] [Indexed: 11/30/2022]
Abstract
AIM OF THE REVIEW To systematically analyze the efficacy and safety of aliskiren for the treatment of hypertension in comparison to placebo, other monotherapy, and various combination therapies. METHOD A PubMed database (1966-June 2008) search was conducted with aliskiren as a search term with limits of humans, written in English, and in title only. Phase III pivotal clinical studies retrieved by PubMed database and resources such as printed labeling, approval letter, pharmacology reviews, and medical reviews posted in Drug@FDA website were evaluated with regard to study design and outcomes of efficacy and safety. RESULTS Six Phase III pivotal clinical studies compared various doses of aliskiren to placebo and some studies compared aliskiren to treatment with other monotherapies or combinations. Aliskiren in doses of 300 mg showed a statistically significant reduction in both systolic and diastolic blood pressure versus placebo. Comparison to other antihypertensive treatments suggest that aliskiren doses of 150 and 300 mg may induce blood pressure changes similar to those seen with moderate doses of hydrochlorothiazide or angiotensin receptor blockers. Aliskiren in combination with angiotensin receptor blockers or hydrochlorothiazide showed additional blood pressure reduction only when higher doses of aliskiren were used. Aliskiren appears to be well tolerated, with diarrhea being the only statistically significant adverse event. CONCLUSION Aliskiren is a novel antihypertensive that exerts its effects through the direct inhibition of renin. Although the drug is well tolerated, its modest effects on blood pressure and the present lack of evidence of impact on objective cardiovascular outcomes appear to limit its utility in the general treatment of hypertension at this time.
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The cost effectiveness of screening newborns for congenital adrenal hyperplasia. Public Health Genomics 2008; 12:67-72. [PMID: 19039250 DOI: 10.1159/000156115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 06/18/2008] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To assess the cost effectiveness of newborn screening for congenital adrenal hyperplasia (CAH) in the U.S. newborn population. METHODS We constructed a decision model to estimate the incremental cost-effectiveness ratio (ICER) of CAH screening compared to a strategy of no screening. Two types of cost effectiveness analyses (CEA) were conducted to measure ICER as net cost per life year (LY): (1) traditional CEA with sensitivity and scenario analyses, and (2) probabilistic CEA. RESULTS ICERs for (1) base-case analysis in traditional CEA and (2) probabilistic CEA were USD 292,000 and USD 255,700 per LY saved in 2005 USD, respectively. ICERs were particularly sensitive to assumptions regarding the mortality rate for the salt wasting type of CAH, in a range from 2 to 9%. The ICERs for best-case and worst-case scenarios were USD 30,900 and USD 2.9 million per LY saved, respectively. CONCLUSIONS Using common benchmarks for cost effectiveness, our results indicate that CAH screening would be unlikely to be considered cost effective unless assumptions favorable to screening were adopted, although it could meet economic criteria used to assess U.S. regulatory policies. A limitation is that the analysis excludes outcomes such as correct assignment of gender and quality of life.
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Development of polyvinyl alcohol–sodium alginate gel-matrix-based wound dressing system containing nitrofurazone. Int J Pharm 2008; 359:79-86. [DOI: 10.1016/j.ijpharm.2008.03.021] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 02/26/2008] [Accepted: 03/18/2008] [Indexed: 11/16/2022]
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Chloroquine-induced nitric oxide increase and cell death is dependent on cellular GSH depletion in A172 human glioblastoma cells. Toxicol Lett 2008; 178:52-60. [DOI: 10.1016/j.toxlet.2008.02.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/31/2008] [Accepted: 02/06/2008] [Indexed: 01/31/2023]
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Preparation and in Vivo Evaluation of Piroxicam-Loaded Gelatin Microcapsule by Spray Drying Technique. Biol Pharm Bull 2008; 31:1284-7. [DOI: 10.1248/bpb.31.1284] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Enhancement of Solubility, Dissolution and Bioavailability of Ibuprofen in Solid Dispersion Systems. Chem Pharm Bull (Tokyo) 2008; 56:569-74. [DOI: 10.1248/cpb.56.569] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Preparation, characterization and in vivo evaluation of ibuprofen binary solid dispersions with poloxamer 188. Int J Pharm 2007; 343:228-37. [PMID: 17597315 DOI: 10.1016/j.ijpharm.2007.05.031] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 04/05/2007] [Accepted: 05/17/2007] [Indexed: 11/20/2022]
Abstract
Ibuprofen-Poloxamer 188 (P 188) binary solid dispersions (SD) with different drug loadings were prepared, characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), and evaluated for solubility, in vitro release, and oral bioavailability of ibuprofen in rats. Loss of their individual surface properties during melting and solidification as revealed by SEM micrographs indicated the formation of effective SDs. Absence or shifting towards the lower melting temperature of the drug peak in SDs and physical mixtures in DSC study indicated the possibilities of its interactions with P 188. However, no such interactions in the solid state were confirmed by FTIR spectra which showed the presence of drug crystalline in SDs. Immediate and complete release of ibuprofen from SDs might be because of the reduction in the drug crystalline due to eutectic formation, and their dosing to fasted rats resulted in a significant increase in the area under curve (AUC) of the plasma concentration versus time curve and the maximum plasma concentration (Cmax), and a significant decrease in the time to reach Cmax (Tmax) over ibuprofen and physical mixtures.
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The effect of beta-cyclodextrin complexation on the bioavailability and hepatotoxicity of clotrimazole. DIE PHARMAZIE 2007; 62:756-759. [PMID: 18236780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Clotrimazole, a poorly water-soluble antimycotic agent, is a promising therapeutic agent for various diseases including cancer and sickle cell anemia. The oral bioavailability and hepatic toxicity of clotrimazole were compared with its beta-cyclodextrin inclusion form which was prepared by the spray-drying method. The inclusion complex gave significantly higher initial plasma concentrations, Cmax and AUC than did clotrimazole alone, indicating that the drug from the inclusion compound could be more easily absorbed in rats. Furthermore, mice treated with the inclusion compound showed significantly higher GOT/GPT values compared to clotrimazole alone. The inclusion compound also induced hypertrophy of hepatic cells by fat accumulation and disappearance of hepatic sinusoids, indications of pathological changes of liver, suggesting that the inclusion compound could induce more severe tissue damage in the liver than clotrimazole alone. Thus, hepatotoxicity of clotrimazole seems to be correlated with the enhanced oral bioavailability by inclusion complexation. Our results suggest that, in the development of a novel oral product, appearance or enhancement of hepatic toxicity must be considered along with oral bioavailability.
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Protective effects of fustin, a flavonoid from Rhus verniciflua Stokes, on 6-hydroxydopamine-induced neuronal cell death. Exp Mol Med 2007; 39:316-26. [PMID: 17603285 DOI: 10.1038/emm.2007.35] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
6-Hydroxydopamine (6-OHDA) is a neurotoxin and is commonly used to generate experimental models of Parkinson's disease (PD). In this study, we investigated the signaling molecules involved in the 6-OHDA-induced cell death using a neuronal catecholaminergic cell line (SK-N-SH cells), and the protective effect of fustin, a flavonoid from Rhus verniciflua Stokes, on 6-OHDA-induced neuronal death. 6-OHDA significantly increased levels of reactive oxygen species (ROS), intracellular Ca(2+) ([Ca(2+)](i)), and p38 phosphorylation. In addition, this ROS increase by 6-OHDA was reduced by pretreatment with N-acetylcysteine (NAC), a free radical scavenger, but not by bis-(o-aminophenoxy)-ethane-N,N,N,N-tetraacetic acid (BAPTA), a Ca(2+) chelator. However, the [Ca(2+)](i) increase induced by 6-OHDA was suppressed by NAC. Moreover, pretreatment with NAC or BAPTA significantly prevented the 6-OHDA-induced increases in p38 phosphorylation, Bax/Bcl-2 ratio, and caspase-3 activity. Although 6-OHDA-increased phosphorylation of p38 was prevented by NAC or BAPTA, inhibition of p38 by SB203580 did not suppress ROS, Bax/Bcl-2 ratio, or caspase-3 activity increases, and only partially prevented 6-OHDA-induced cell death, thus demonstrating that p38 activation is a component of a signaling pathway leading to the initiation of 6-OHDA-induced cell death, which acts in parallel with an ROS-Ca(2+)-Bcl-2-caspase-3 pathway. Moreover, fustin not only suppressed 6-OHDA-induced cell death in a concentration-dependent manner but also blocked 6-OHDA-induced increases in ROS, [Ca(2+)](i), Bax/Bcl-2 ratio, caspase-3 activity, and p38 phosphorylation. These results suggest that fustin exerts neuroprotection against 6-OHDA-induced cell death.
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The effect of 1-furan-2-yl-3-pyridine-2-yl-propenone on pharmacokinetic parameters of warfarin. Arch Pharm Res 2007; 30:898-904. [PMID: 17703744 DOI: 10.1007/bf02978843] [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: 11/27/2022]
Abstract
1-Furan-2-yl-3-pyridine-2-yl-propenone (FPP-3) is an investigatory drug which has a dual inhibitory action on cyclooxygenase (COX) and 5-lipoxygenase (5-LOX). We examined its effect on the pharmacokinetics of warfarin. Three consecutive days of pretreatment with 17 mg/kg of FPP-3 had no significant effect on the pharmacokinetic parameters of warfarin when orally administered to rats. A higher dosage of FPP-3 however, did cause significant changes in the pharmacokinetic parameters of wafarin. The cytochrome P450 activity test demonstrated that the metabolism of R-warfarin was significantly inhibited by FPP-3 while there was little or no inhibition of the metabolism of S-warfarin, which is mainly responsible for its anticoagulant effect. Therefore, it appears that the alteration in the pharmacokinetic parameters of warfarin was due to the inhibitory effect of FPP-3 on the metabolism of R-warfarin. Although there was a significant increase in the plasma concentration, the area under the curve, half life of warfarin, and prothrombin time were not significantly changed. Based on these findings, the pharmacokinetic drug interaction between FPP-3 and warfarin mainly involves R-warfarin and, therefore, this interaction may not be of clinical significance in terms of warfarin-related toxicity.
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Preparation, Characterization and Evaluation of Coenzyme Q10 Binary Solid Dispersions for Enhanced Solubility and Dissolution. Biol Pharm Bull 2007; 30:1171-6. [PMID: 17541177 DOI: 10.1248/bpb.30.1171] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phase solubility behavior of coenzyme Q10 (CoQ10) at 25 degrees C in various molar solutions of poloxamer 188 (P188) in water was observed and their binary solid dispersions (BSD) at different weight ratios were prepared by a simple, rapid, cost effective, uncomplicated and potentially scalable low temperature melting method. BSDs were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), and evaluated for improved solubility at 25 degrees C and 37 degrees C and in-vitro release of CoQ10 at 37 degrees C in distilled water. Solubility of CoQ10 increased with increasing concentrations of P188 in water. Gibbs free energy (deltaG(o)tr) values were all negative indicating the spontaneous nature of CoQ10 solubilization and decreased with increasing concentration of P188 demonstrating that the reaction conditions became more favorable as the concentration of P188 increased. DSC and SEM analysis indicated that the homogeneity of dispersion was not at the molecular level. However, BSDs exhibited a remarkably improved aqueous solubility and dissolution of CoQ10.
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Reduced renal toxicity of nanoparticular amphotericin B micelles prepared with partially benzylated poly-L-aspartic acid. Biol Pharm Bull 2006; 29:1700-5. [PMID: 16880628 DOI: 10.1248/bpb.29.1700] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A partially benzylated poly-L-aspartic acid (PBPA) was synthesized and investigated as a potential renal protective agent for the toxicity of amphotericin B (AmB) when the drug was administered as nanoparticular micelle. Nanoparticular AmB micelles were prepared by slow dialysis of the drug against distilled water at the elevated pH of 11.5 and subsequent sonication with the polymer solution. The resulting nanoparticular AmB micelles with PBPA showed an average diameter of about 20 nm and demonstrated significantly less damage to the tubular cells of the rat's kidney in terms of transmission electron microscopic study. There was little or no damage on the brush border of tubular cells 7 d after single intravenous dose of AmB 5 mg/kg in the rats when the drug was administered as nanoparticuar micelles with PBPA. The reduced renal toxicity appears to be due to the alteration of self-aggregation status of AmB. Molar absorptivity of AmB at 412 nm (a marker for the prevalence of non-aggregated AmB) was significantly higher in the nanoparticular AmB micelles with PBPA than those in AmB micelles without PBPA as well as in Fungizone. This result indicates an association of the reduced nephrotoxicity and the prevalence of non-aggregated AmB. Mechanisms for the reduced renal toxicity may also include the formation of electrostatic complex between anionic groups of PBPA and hydroxyl groups of AmB.
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Simultaneous determination of cefatrizine and clavulanic acid in dog plasma by HPLC. J Pharm Biomed Anal 2004; 35:221-31. [PMID: 15030898 DOI: 10.1016/j.jpba.2004.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2003] [Revised: 12/26/2003] [Accepted: 01/06/2004] [Indexed: 11/30/2022]
Abstract
A rapid and specific high-performance liquid chromatographic method was developed and validated for the simultaneous determination of cefatrizine and clavulanic acid in the plasma of beagle dog. The sample pretreatment procedure involved reaction of clavulanic acid with 1,2,4-triazole, which readily produced a derivative with its maximum UV absorption at 314 nm. This derivative was separated in a reverse-phase C-18 column without being interfered by other components present in plasma. Cefatrizine, however, was not derivatized and, therefore determined directly at 269 nm. Sulfanilamide was used as an internal standard. The retention times of sulfanilamide, the derivative, and cefatrizine were, 3.5, 4.9, and 6.0 min, respectively. The assay showed linearity from 2 to 100 microg/ml for cefatrizine and from 1 to 50 microg/ml for clavulanic acid. Precision expressed as R.S.D. ranged from 4.2 to 18.2% for cefatrizine and 5.5 to 15.8% for clavulanic acid. Accuracy ranged from 97.9 to 120% (lower limit of quantitation) for cefatrizine and from 97.7 to 119.2% for clavulanic acid. Extraction efficiencies for cefatrizine, clavulanic acid, and internal standard from dog plasma averaged 79.8+/-5.8%, 84.8+/-6.2%, and 89.0+/-3.8%, respectively. This method was employed successfully to follow the time course of the concentration of cefatrizine and clavulanic acid in beagle dogs following oral administration of cefatrizine and clavulanic acid.
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Modulation of the catalytic activity of brain succinic semialdehyde reductase by reaction with pyridoxal 5'-phosphate. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:274-9. [PMID: 9249037 DOI: 10.1111/j.1432-1033.1997.00274.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An NADPH-dependent succinic semialdehyde reductase from bovine brain was inactivated by pyridoxal 5'-phosphate. Spectral evidence is presented to indicate that the inactivation proceeds through formation of a Schiff's base with amino groups of the enzyme. After sodium borohydride reduction of the inactivated enzyme, it was observed that 1 mol phosphopyridoxyl residue was incorporated/mol enzyme monomer. The coenzyme, NADPH, protected the enzyme against inactivation by pyridoxal 5'-phosphate. After tryptic digestion of the enzyme modified with pyridoxal 5'-phosphate in the presence and absence of NADPH followed by [1H]NaBH4 reduction, a radioactive peptide absorbing at 310 nm was isolated by reverse-phase HPLC. The amino acid sequence of the peptide identified a portion of the pyridoxal-5'-phosphate-binding site as the region containing the sequence I-L-E-N-I-Q-V-F-X-K, where X indicates that the phenylthiohydantoin amino acid could not be assigned. The missing residue, however, can be designated as a phosphopyridoxyl lysine as interpreted from the result of amino acid composition of the peptide. It is suggested that the catalytic function of succinic semialdehyde reductase is modulated by binding of pyridoxal 5'-phosphate to a specific lysyl residue at or near the coenzyme-binding site of the protein.
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Distribution of succinic semialdehyde reductase in rat brain. Mol Cells 1997; 7:13-20. [PMID: 9085259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Succinic semialdehyde reductase (SSR) that catalyzes the reduction of succinic semialdehyde (SSA) to gamma-hydroxybutyrate (GHB) has been identified as one of the NADPH-dependent aldehyde reductases. Reduction of SSA to GHB strongly supports the proposal that GHB biosynthesis may be an important step in the GABA shunt. It is pharmacologically significant in anesthesia, evoking the state of sleep, and an increase in brain dopamine level. Monoclonal antibodies against bovine brain succinic semialdehyde reductase were produced. Using the anti-succinic semialdehyde reductase antibodies, we investigated the distribution of brain succinic semialdehyde reductase in rat brain. The brain tissues were sectioned with a basis on the rat brain atlas of Paxinos and were stained by the immunoperoxidase staining method using monoclonal antibodies. In the section of the frontal lobe, immunoreactive cells were observed in the lateral septal area, the ventral pallidum, which belongs to the substantia innominata. We could observe immunoreactive cells in the reticular thalamic nucleus, which is closely related with 'sleeping', the basal nuclei of Meynert, which is associated with Alzheimer's disease, and hypothalamic nuclei. Immunoreactive cells were also shown in raphe nuclei or the reticular formation of the midbrain, cerebellum, and inferior olivary nuclei of the medulla oblongata. Succinic semialdehyde reductase-immunoreactive cells were distributed extensively in rat brain, especially immunoreactive cells were strongly observed in the areas associated with the limbic system and reticular formation.
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