A liquid chromatography method was developed and validated for the determination of phenobarbital in human plasma using phenytoin as internal standard. The drugs were extracted from plasma by liquid-liquid extraction and separated isocratically on a C12 analytical column, maintained at 35 ºC, with water:acetonitrile:methanol (58.8:15.2:26, v/v/v) as mobile phase, run at a flow rate of 1.2 mL/min with detection at 205 nm. The method was linear in the range of 0.1-4 μg/mL (r²=0.9999) and demonstrated acceptable results for the precision, accuracy and stability studies. The method was successfully applied for the bioequivalence study of two tablet formulations (test and reference) of phenobarbital 100 mg after single oral dose administration to healthy human volunteers.

OBJETIVO: Comparar a biodisponibilidade de duas formulações de glimepirida em 26 voluntários sadios de ambos os sexos. MATERIAL E MÉTODOS: O estudo foi aberto, cruzado e randomizado com dois períodos e wash out de 14 dias. As amostras foram obtidas em um intervalo de 48 horas. As concentrações de glimepirida foram analisadas por HPLC MS/MS. Das curvas de concentração de glimepirida no plasma versus tempo, foram obtidos os seguintes parâmetros farmacocinéticos: ASC(0-t), ASC(0-<FONT FACE=Symbol>¥</FONT>), Cmax, Ke, Tmax e T1/2. RESULTADOS: A razão entre as média geométricas de Glimepirida/Amaryl® 4 mg foi de 102,35% para ASC(0-t); 102,35% para ASC(0-<FONT FACE=Symbol>¥</FONT>) e 99,31% para Cmax. Os intervalos de confiança de 90% (IC 90%) foram de 92,62-109,55%; 95,62-109,55% e 88,60-111,32%, respectivamente. CONCLUSÃO: Como o IC 90% para Cmax, ASC(0-t) e ASC(0-<FONT FACE=Symbol>¥</FONT>) estava dentro do intervalo de 80-125%, concluiu-se que ambas as formulações foram bioequivalentes de acordo com o grau e a extensão de sua absorção.

OBJECTIVE: To compare the bioavailability of two glimepiride 4-mg tablet formulation in 26 healthy volunteers of both sexes. MATERIAL AND METHODS: The study was conducted open with randomized two-period crossover design and a 14-day washout period. Samples were obtained over a 48-hour interval. Glimepiride concentrations were analyzed by LC-MS-MS. From the glimepiride plasma concentration versus time curves the following pharmacokinetic parameters were obtained: AUC(0-last), AUC(0-t), AUC(0-<FONT FACE=Symbol>¥</FONT>), Ke, T1/2, Cmax, and Tmax. RESULTS: Geometric mean of Glimepirida/Amaryl® 4 mg was 102.35% for AUC(0-t), 102.35% for AUC(0-<FONT FACE=Symbol>¥</FONT>) and 99.31% for Cmax. The 90% CI was 92.62-109.55%; 95.62-109.55% e 88.60-111.32%, respectively. CONCLUSION: Since the 90% CI for both Cmax, AUC(0-t), and AUC(0-<FONT FACE=Symbol>¥</FONT>) were within the interval of 80-125%, it was concluded that both formulations were bioequivalent, according to both the rate and extent of absorption.