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: AUClast and Cmax. RESULTS: The limit of quantification was 0.1 microg/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 Cmax, 109.4% (104.8%-114.2%) for AUClast. CONCLUSION: Since the 90% CI for AUClast and Cmax 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.

Comparative bioavailability study with two pantoprazole delayed-released tablet formulations administered with and without food in healthy subjects.

OBJECTIVE: To assess the comparative bioavailability of two formulations (40 mg delayed-released [DR] tablet; test and reference) of pantoprazole (CAS 102625-70-7) in healthy volunteers of both sexes, with and without food. METHODS: The study was conducted using an open, randomized, two-period crossover design with a 1-week washout interval, in two groups, with and without food. Plasma samples were obtained for up to 24 h post dose. Plasma pantoprazole concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM). From the pantoprazole plasma concentration vs. time curves, the pharmacokinetic parameters AUC(last) and C(max) were obtained, with and without food. RESULTS: The limit of quantification was 5 ng/mL for plasma pantoprazole analysis. The geometric mean and 90% confidence interval CI of test/reference percent ratios were, without and with food, respectively: 104.6540% (90.8616%-120.5401%) and 99.9708% (90.9987%-109.8275%) for C(max), 95.6634% (85.2675%-107.3267%) and 89.3500% (83.6630%-95.4237%) for AUC(last). CONCLUSION: Since the 90% CI for AUC(last) and C(max) ratios were within the 80-125% interval proposed by the US FDA, it was concluded that pantoprazole 40 mg DR tablet (test formulation) with and without food was bioequivalent to the reference 40 mg DR tablet for both the rate and extent of absorption.

Clonazepam quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry in a bioequivalence study.

A rapid, sensitive and specific method for quantifying clonazepam in human plasma using diazepam as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using a hexane/diethylether (20 : 80, v/v) solution. The extracts were analysed by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS-MS). Chromatography was performed on a Jones Genesis C8 4 microm analytical column (100 x 2.1 mm i.d.). The method had a chromatographic run time of 3.0 min and a linear calibration curve over the range 0.5-50 ng/ml (r2 > 0.9965). The limit of quantification was 0.5 ng/ml. This HPLC/MS/MS procedure was used to assess the bioequivalence of two clonazepam 2 mg tablet formulations (clonazepam test formulation from Ranbaxy Laboratories Ltd and Rivotril from Roche Laboratórios Ltda as standard reference formulation).