CYP3A5*3A allele is associated with reduced lowering-lipid response to atorvastatin in individuals with hypercholesterolemia

Background: The cytochrome P450 isoenzyme 3A5 (CYP3A5) has an important role on biotransformation of xenobiotics. CYP3A5 SNPs have been associated with variations on enzyme activity that can modify the metabolism of several drugs. Methods: In order to evaluate the influence of CYP3A5 variants on response to lowering-cholesterol drugs, 139 individuals with hypercholesterolemia were selected. After a wash-out period of 4 weeks, individuals were treated with atorvastatin (10 mg/day/4 weeks). Genomic DNA was extracted by a salting-out procedure. CYP3A5*3C, CYP3A5*6 and CYP3A5*1D were analyzed by PCR-RFLP and DNA sequencing. Results: >Frequencies of the CYP3A5*3C and CYP3A5*1D alleles were lower in individuals of African descent (*3C: 47.8% and *1D: 55.2%) than in non-Africans (*3C: 84.9% and *1D 84.8%, p<0.01). Non-Africans carrying *3A allele (*3C and *1D combined alleles) had lower total and LDL-cholesterol response to atorvastatin than non-*3A allele carriers (p<0.05). Conclusion: CYP3A5*3A allele is associated with reduced cholesterol-lowering response to atorvastatin in non-African individuals. (C) 2008 Elsevier B.V. All rights reserved.

Comparative bioavailability of cefuroxime axetil suspension formulations administered with food in healthy subjects

Objective: To assess the comparative bioavailability of two formulations (250 mg/5 mL suspension) of cefuroxime axetil (CAS 64544-07-6), administered with food, in healthy volunteers of both sexes. Methods: The study was conducted using an open, randomized, two-period crossover design with a 1-week washout interval. Plasma samples were obtained for up to 12 h post dose. Plasma cefuroxime axetil concentrations were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) with negative ion electrospray ionization using multiple reactions monitoring (MRM). From the cefuroxime axetil plasma concentration vs. time curves, the following pharmacokinetic parameters were obtained: AUC(last) and C(max). Results: The limit of quantification was 0.1 mu g/mL for plasma cefuroxime axetil analysis. The geometric mean and 90% confidence interval CI of test/reference product percent ratios were: 106.1% (100.8%-111.8%) for C(max), 109.4% (104.8%-114.2%) for AUC(last). Conclusion: Since the 90% Cl for AUC(last) and C(max) ratios were within the 80-125 % interval proposed by the US FDA, it was concluded that cefuroxime axetil (test formulation, 250 mg/5 mL suspension) was bioequivalent to a reference formulation under fed conditions, for both the rate and extent of absorption.

Quantification of chlordesmethyldiazepam by liquid chromatography-tandem mass spectrometry: application to a cloxazolam bioequivalence study

A rapid, sensitive and specific LC-MS/MS method was developed and validated for quantifying chlordesmethyldiazepam (CDDZ or delorazepam), the active metabolite of cloxazolam, in human plasma. In the analytical assay, bromazepam (internal standard) and CDDZ were extracted using a liquid-liquid extraction (diethyl-ether/hexane, 80/20, v/v) procedure. The LC-MS/MS method on a RP-C18 column had an overall run time of 5.0 min and was linear (1/x weighted) over the range 0.5-50 ng/mL (R > 0.999). The between-run precision was 8.0% (1.5 ng/mL), 7.6% (9 ng/mL), 7.4% (40 ng/mL), and 10.9% at the low limit of quantification-LLOQ (0.500 ng/mL). The between-run accuracies were 0.1, -1.5, -2.7 and 8.7% for the above mentioned concentrations, respectively. All current bioanalytical method validation requirements (FDA and ANVISA) were achieved and it was applied to the bioequivalence study (Cloxazolam-test, Eurofarma Lab. Ltda and Olcadil (R)-reference, Novartis Biociencias S/A). The relative bioavailability between both formulations was assessed by calculating individual test/reference ratios for Cmax, AUClast and AUCO-inf. The pharmacokinetic profiles indicated bioequivalence since all ratios were as proposed by FDA and ANVISA. Copyright (C) 2009 John Wiley & Sons, Ltd.

An artificial nanoemulsion carrying paclitaxel decreases the transplant heart vascular disease: A study in a rabbit graft model

Objective: In previous studies cholesterol-rich nanoemulsions (LDE) resembling low-density lipoprotein were shown to concentrate in atherosclerotic lesions of rabbits. Lesions were pronouncedly reduced by treatment with paclitaxel associated with LDE. This study aimed to test the hypothesis of whether LDE-paclitaxel is able to concentrate in grafted hearts of rabbits and to ameliorate coronary allograft vasculopathy after the transplantation procedure. Methods: Twenty-one New Zealand rabbits fed 0.5% cholesterol were submitted to heterotopic heart transplantation at the cervical position. All rabbits undergoing transplantation were treated with cyclosporin A (10 mg . kg(-1) . d(-1) by mouth). Eleven rabbits were treated with LDE-paclitaxel (4 mg/kg body weight paclitaxel per week administered intravenously for 6 weeks), and 10 control rabbits were treated with 3 mL/wk intravenous saline. Four control animals were injected with LDE labeled with [(14)C]-cholesteryl oleate ether to determine tissue uptake. Results: Radioactive LDE uptake by grafts was 4-fold that of native hearts. In both groups the coronary arteries of native hearts showed no stenosis, but treatment with LDE-paclitaxel reduced the degree of stenosis in grafted hearts by 50%. The arterial luminal area in grafts of the treated group was 3-fold larger than in control animals. LDE-paclitaxel treatment resulted in a 7-fold reduction of macrophage infiltration. In grafted hearts LDE-paclitaxel treatment reduced the width of the intimal layer and inhibited the destruction of the medial layer. No toxicity was observed in rabbits receiving LDE-paclitaxel treatment. Conclusions: LDE-paclitaxel improved posttransplantation injury to the grafted heart. The novel therapeutic approach for heart transplantation management validated here is thus a promising strategy to be explored in future clinical studies. (J Thorac Cardiovasc Surg 2011;141:1522-8)

Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome

Background: Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem(R), in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. Methods: Fifteen male Wistar rats were intravenously photosensitized with 1.5 mg/kg body weight of Photogem(R). Laser-induced fluorescence spectroscopy at 532nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. Results: Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. Conclusions: As a consequence of these results, this study suggests that photosensitizer surface spatial distribution should be taken into account in photodynamic therapy dosimetry, as this will help to better predict clinical results. (C) 2010 Elsevier B.V. All rights reserved.

Comparative bioavailability of three ibuprofen formulations in healthy human volunteers

Objective: To assess the bioequivalence of three ibuprofen formulations (Test formulation: ibuprofen (400 mg capsule) manufactured by Cardinal Health Brasil 402 Ltda. (Sorocaba, Brazil) and licensed to Boehringer Ingelheim do Brasil Quim. e Farm. Ltda. (Sao Paulo, Brazil); Reference formulation (1): ibuprofen (Advil (R); 2 x 200 mg coated tablet) from Wyeth-Whitehall Ltda. (Itapevi, Brazil); Reference formulation (2): ibuprofen (Alivium (R); 8 ml x 50 mg/ml solution) from Schering Plough S.A. (Rio de Janeiro, Brazil)) in 24 healthy volunteers of both sexes. Methods: The study was conducted using an open, randomized, three-period crossover design with at least 5-day washout interval. Plasma samples were obtained over a 24-h period. Plasma ibuprofen concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with negative ion electrospray ionization using multiple reaction monitoring (MRM). The following pharmacokinetic parameters were obtained from the ibuprofen plasma concentration vs. time curves: AUC(last), AUC(trunctmax) AUC(inf) and C-max. Results: The limit of quantification for ibuprofen was 0.1 mu g x ml(-1). The geometric mean with corresponding 90% confidence interval (CI) for Test/Reference (1) percent ratios were 114.24% (90% CI = 105.67, 123.50%) for C-max, 98.97% (90% CI = 94.69, 103.44%) for AUC(last) and 99.40% (90% CI = 95.21, 103.78%) for AUCinf. The geometric mean and respective 90% confidence interval (CI) for Test/Reference (2) percent ratios were 108.38% (90% Cl = 100.195, 117.25%) for C-max, 100.79% (90% CI = 96.39, 105.40%) for AUC(last) and 101.26% (90% CI = 96.94, 105.77%) for AUC(inf); t(max) for the 400 mg Test capsule was shorter than that for the 2 x 200 mg Reference (1) tablets (p < 0.002). Conclusion: Since the 90% CI for AUC(last), AUC(inf) and C-max ratios were within the 80 - 125% interval proposed by the US FDA, it was concluded that ibuprofen formulation manufactured by Cardinal Health Brasil 402 Ltda. and licensed to Boehringer Ingelheim do Brasil Quim. e Farm. Ltda. is bioequivalent to the Advil (R) and Alivium (R) formulations with regard to both the rate and the extent of absorption.