Determination of bromazepam in human plasma by high-performance liquid chromatography with electrospray ionization tandem mass spectrometric detection: application to a bioequivalence study.

A simple method using a one-step liquid-liquid extraction (LLE) followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the determination of bromazepam in human plasma, using lorazepam as internal standard. The acquisition was performed in the multiple reaction monitoring mode, monitoring the transitions: m/z 316 > 182 for bromazepam and m/z 321 > 275 for lorazepam. The method was linear over the studied range (1-100 ng ml(-1)), with r(2) > 0.98, and the run time was 2.5 min. The intra- and inter-assay precisions were 2.7-14.6 and 4.1-17.3%, respectively and the intra- and inter-assay accuracies were 87-111 and 75.8-109.5%, respectively. The mean recovery was 73.7%, ranging from 64.5 to 79.7%. The limit of quantification was 1 ng ml(-1). At this concentration the mean intra- and inter-assay precisions were 14.6 and 7.1%, respectively, and the mean intra- and inter-assay accuracies were 102.5 and 104%, respectively. Bromazepam stability was evaluated and the results showed that the drug is stable in standard solution and in plasma samples under typical storage and processing conditions. The method was applied to a bioequivalence study in which 27 healthy adult volunteers (14 men) received single oral doses (6 mg) of reference and test bromazepam formulations, in an open, two-period, randomized, crossover protocol. The 90% confidence interval of the individual ratios (test formulation/reference formulation) for C(max) (peak plasma concentration), AUC(0-96) and AUC(0-inf) (area under the plasma concentration versus time curve from time zero to 96 h and to infinity, respectively) were within the range 80-125%, which supports the conclusion that the test formulation is bioequivalent to the reference formulation regarding the rate and extent of bromazepam absorption.

One-step liquid-liquid extraction of cocaine from urine samples for gas chromatographic analysis.

An improved technique for cocaine extraction from urine samples for gas chromatographic (GC) analysis is described. Employing a simple liquid-liquid extraction (LLE) of cocaine with a mixture of ethyl ether:isopropanol (9:1) the method presents a mean recovery of 74.49%. Limit of detection (LOD) and limit of quantification (LOQ) were 5 and 20 ng/ml, respectively. The method is highly precise (coefficient of variation (CV) <8%) and linear from 20 to 2000 ng/ml. It can he applied to detect the presence of cocaine in urine as a marker of its recent use in drug abuse treatment protocols.

Identificaçäo de 3, 4-metilenodioximetanfetamina (MDMA) e compostos relacionados por cromatografia em fase gasosa e espectrometria de massas em comprimidos de Ecstasy apreendidos em Säo Paulo / Identification of 3, 4-methylenedioxymethamphetamine (MDMA) and related compounds by gas chromatography-mass spectrometry in Ecstasy tablets seized in Säo Paulo, Brazil

Foram analisados comprimidos de Ecstasy provenientes de sete diferentes lotes da droga apreendidos em Säo Paulo, visando à pesquisa de metilenodioxifenilalquilaminas. Em seis amostras foi detectada a presença de 3, 4-metilenodioximetanfetamina (MDMA), sendo que numa delas foi encontrada também cafeína. Apenas numa, foi identificada a 3, 4-metilenodioxietilanfetamina (MDEA). A cromatografia em fase gasosa com detector de nitrogênio/fósforo (CG/DNP) e a espectrometria de massas acoplada à cromatografia em fase gasosa (CG/EM) foram utilizadas como técnica de triagem e confirmaçäo, respectivamente