RESUMO
BACKGROUND: A high-throughput bioanalytical method using 96-blade thin film microextraction (TFME) and LC-MS/MS for the analysis of repaglinide (RPG) and two of its main metabolites was developed and used for an in vitro metabolism study. RESULTS: The target analytes were extracted from human microsomal medium by a 96-blade-TFME system employing the low-cost prototype 'SPME multi-sampler' using C18 coating. Method validation showed recoveries around 90% for all analytes and was linear over the concentration range of 2-1000 ng ml(-1) for RPG and of 2-500 ng ml(-1) for each RPG metabolite. CONCLUSION: The method was applied to an in vitro metabolism study of RPG employing human liver microsomes and proved to be very useful for this purpose.
Assuntos
Carbamatos/uso terapêutico , Cromatografia Líquida/métodos , Hipoglicemiantes/uso terapêutico , Técnicas In Vitro/métodos , Piperidinas/uso terapêutico , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Carbamatos/administração & dosagem , Humanos , Hipoglicemiantes/administração & dosagem , Piperidinas/administração & dosagemRESUMO
BACKGROUND: An enantioselective analytical method was developed and validated for determination of venlafaxine and its metabolites O-desmethylvenlafaxine and N-desmethylvenlafaxine in plasma samples. The method employed LC-MS/MS analysis and hollow-fiber liquid-phase microextraction (HF LPME) for sample preparation. RESULTS: After HF LPME optimization the following condition was established: sample volume of 4 ml, sample agitation at 1750 rpm, 20 min of extraction, 0.1 mol/l acetic acid as acceptor phase, 1-octanol as organic phase and donor phase pH adjustment to 10. Under these conditions, the method was linear over the concentration range of 5-500 ng/ml with quantification limits of 5 ng/ml. CONCLUSION: The use of HF LPME for sample preparation provided suitable recoveries, efficient clean-up and low consumption of organic solvent.
Assuntos
Antidepressivos de Segunda Geração/sangue , Cromatografia Líquida de Alta Pressão , Cicloexanóis/sangue , Microextração em Fase Líquida/métodos , Espectrometria de Massas em Tandem , 1-Octanol/química , Antidepressivos de Segunda Geração/metabolismo , Antidepressivos de Segunda Geração/normas , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Cicloexanóis/isolamento & purificação , Cicloexanóis/metabolismo , Cicloexanóis/normas , Succinato de Desvenlafaxina , Humanos , Concentração de Íons de Hidrogênio , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/normas , Estereoisomerismo , Espectrometria de Massas em Tandem/normas , Cloridrato de VenlafaxinaRESUMO
Pioglitazone (PGZ), a thiazolidinedione antidiabetic agent, is reported as a potent and selective activator of peroxisome proliferator-activated receptor γ (PPAR γ). This drug has been widely prescribed for the treatment of Type 2 diabetes mellitus. In this regard, this manuscript presents, for the first time, an alternative electrophoretic method for PGZ and its main metabolites determination in rat liver microsomal fraction. The electrophoretic analyses were performed using an uncoated fused-silica capillary of 50 µm id, 48 cm in total length and 40 cm in effective length, and 50 mmol/L sodium phosphate buffer solution (pH 2.5). All experiments were carried out under the normal mode. The capillary temperature was set at 35°C and a constant voltage of +30 kV was applied during the analyses. Samples were introduced into the capillary by hydrodynamic injection (50 mbar, 15 s) and detection was performed at 190 nm. The sample preparation procedure, based on hollow-fiber liquid-phase microextraction, was optimized using multifactorial experiments. Next, the following optimal condition was established: sample agitation at 1500 rpm, extraction for 15 min, 0.01 mol/L hydrochloric acid as acceptor phase, 1-octanol as organic phase, and donor phase pH adjustment to 6.0. The method demonstrated LOQs of 200 ng/mL. Additionally, it was linear over the concentration range of 200-25,000 ng/mL for PGZ and 200-2000 ng/mL for the metabolites. Finally, the validated method was employed to study the in vitro metabolism of PGZ using rat liver microsomal fraction.
Assuntos
Eletroforese Capilar/métodos , Microextração em Fase Líquida/métodos , Microssomos Hepáticos/metabolismo , Tiazolidinedionas/análise , Tiazolidinedionas/metabolismo , Animais , Calibragem , Hipoglicemiantes/análise , Hipoglicemiantes/metabolismo , Hipoglicemiantes/farmacocinética , Masculino , Pioglitazona , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Temperatura , Tiazolidinedionas/farmacocinéticaRESUMO
BACKGROUND: An enantioselective bioanalytical method using dispersive liquid-liquid microextraction (DLLME) and LC-MS/MS was developed for the chiral analysis of ranolazine (RNZ) and one of its metabolites (desmethyl ranolazine [DRNZ]). RESULTS: The analytes were extracted from microsomal medium by DLLME, using chloroform as extractor solvent and acetone as dispersive solvent. The enantiomers of RNZ and DRNZ were analyzed simultaneously for the first time using a Chiralcel OD-H(®). Method validation showed recoveries in the order of 55 and 45%, and LLOQ of 25 and 10 ng ml(-1) for the enantiomers of RNZ and DRNZ, respectively. Linearity was established in the concentration range of 10 to 1000 and 25 to 2500 ng ml(-1) for each DRNZ and RNZ enantiomer, respectively. CONCLUSION: The unprecedented use of DLLME was demonstrated to be very useful for sample preparation of microsomal matrix. Furthermore, the in vitro metabolism of RNZ was enantioselective.
Assuntos
Acetanilidas/análise , Cromatografia Líquida/métodos , Inibidores Enzimáticos/análise , Microextração em Fase Líquida/métodos , Piperazinas/análise , Espectrometria de Massas em Tandem/métodos , Acetanilidas/química , Animais , Inibidores Enzimáticos/química , Masculino , Microssomos Hepáticos/química , Piperazinas/química , Ranolazina , Ratos , Ratos Wistar , EstereoisomerismoRESUMO
A high-performance liquid chromatography (HPLC) method is presented for the simultaneous determination of midodrine and desglymidodrine (DMAE) in Czapek-Dox culture medium, to be used in biotransformation studies by fungi. The HPLC analysis was conducted using a Lichrospher 100 RP18 column, acetonitrile-40 mmol/L formic acid solution (60:40, v/v) as mobile phase, and ultraviolet detection at 290 nm. The sample preparation was conducted by liquid-liquid extraction using ethyl acetate as extractor solvent. The method was linear over the concentration range of 0.4-40.0 µg/mL for midodrine (r ≥ 0.9997) and DMAE (r ≥ 0.9998). Within-day and between-day precision and accuracy were evaluated by relative standard deviations (≤ 8.2%) and relative errors (-7.3 to 7.4%), respectively. The validated method was used to assess midodrine biotransformation by the fungi Papulaspora immersa Hotson SS13, Botrytis cinerea UCA 992 and Botrytis cinerea 2100 under static and shaken conditions. Under shaken conditions, the biotransformation of midodrine to DMAE was more efficient for all studied fungi, especially for the fungus Botrytis cinerea 2100, which converted 42.2% of midodrine to DMAE.
Assuntos
Ascomicetos/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Botrytis/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Meios de Cultura/análise , Midodrina/análogos & derivados , Midodrina/metabolismo , Ascomicetos/crescimento & desenvolvimento , Técnicas de Cultura Celular por Lotes/instrumentação , Biotransformação , Botrytis/crescimento & desenvolvimento , Meios de Cultura/metabolismo , Midodrina/análiseRESUMO
A new high-performance liquid chromatographic method with triple quadrupole mass spectrometry detection was developed and validated for the quantification of zopiclone enantiomers in rat brain samples. Zopiclone enantiomers were resolved on a CHIRALPAK AD column with a mobile phase consisting of acetonitrile/ethanol/methanol (60:20:20, v/v/v) at a flow rate of 1.3 mL min(-1). Moclobemide was used as internal standard. The sample treatment procedure was carried out employing solid-phase extraction, yielding mean absolute recoveries of 89.6 and 91.7% for each zopiclone enantiomer. The validated method showed linearity in the range of 0.29-344.8 ng g(-1), with quantification limits of 0.29 ng g(-1) for both enantiomers. Precision and accuracy were within acceptable levels of confidence (<15%). The method was applied in a pilot study of zopiclone kinetic disposition in rats. It could be observed that the levels of (+)-(S)-zopiclone were always higher than those of (-)-(R)-zopiclone, confirming the stereoselective disposition of zopiclone.
Assuntos
Compostos Azabicíclicos/análise , Compostos Azabicíclicos/farmacologia , Encéfalo/efeitos dos fármacos , Cromatografia Líquida/métodos , Piperazinas/análise , Piperazinas/farmacologia , Espectrometria de Massas em Tandem/métodos , Acetonitrilas/química , Animais , Técnicas de Química Analítica , Etanol/química , Hipnóticos e Sedativos/análise , Hipnóticos e Sedativos/farmacologia , Cinética , Masculino , Metanol/química , Modelos Químicos , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , EstereoisomerismoRESUMO
A capillary electrophoretic enantioselective method with UV detection was developed and validated for the simultaneous quantification of zopiclone enantiomers and its impurities, zopiclone-N-oxide enantiomers, and 2-amino-5-chloropyridine, in tablets. The analytes were extracted from the tablets using ACN and were separated in an uncoated fused-silica capillary (50 µm, 42 cm effective length, 50 cm total length) using 80 mM sodium phosphate buffer pH 2.5 and 5 mM carboxymethyl-ß-cyclodextrin as running buffer. The analytes and the internal standard (trimethoprim) were detected at 305 and 200 nm, respectively. A voltage of 27 kV was applied and the capillary temperature was maintained at 25°C. All enantiomers were analyzed within 8 min and linear calibration curves over the concentration range of 0.4-0.8 mg mL⻹ for each zopiclone enantiomer, 0.8-1.6 µg mL⻹ for 2-amino-5-chloropyridine and 0.4-0.8 µg mL⻹ for each zopiclone-N-oxide enantiomer were obtained. The coefficients of correlation obtained for the linear curves were greater than 0.99. The intra-day and inter-day accuracy and precision were lower than 2% for all analytes. This validated method was employed to study the degradation and racemization of zopiclone under stress conditions. This application demonstrated the importance of a stability-indicating assay method for this drug.
Assuntos
Compostos Azabicíclicos/análise , Eletroforese Capilar/métodos , Piperazinas/análise , Piridinas/análise , Compostos Azabicíclicos/química , Contaminação de Medicamentos , Estabilidade de Medicamentos , Análise dos Mínimos Quadrados , Limite de Detecção , Piperazinas/química , Piridinas/química , Reprodutibilidade dos Testes , Estereoisomerismo , Comprimidos/químicaRESUMO
An high performance liquid chromatography (HPLC) method for the enantioselective determination of donepezil (DPZ), 5-O-desmethyl donepezil (5-ODD), and 6-O-desmethyl donepezil (6-ODD) in Czapek culture medium to be applied to biotransformation studies with fungi is described for the first time. The HPLC analysis was carried out using a Chiralpak AD-H column with hexane/ethanol/methanol (75:20:5, v/v/v) plus 0.3 % triethylamine as mobile phase and UV detection at 270 nm. Sample preparation was carried out by liquid-liquid extraction using ethyl acetate as extractor solvent. The method was linear over the concentration range of 100-10,000 ng mL(-1) for each enantiomer of DPZ (r ≥ 0.9985) and of 100-5,000 ng mL(-1) for each enantiomer of 5-ODD (r ≥ 0.9977) and 6-ODD (r ≥ 0.9951). Within-day and between-day precision and accuracy evaluated by relative standard deviations and relative errors, respectively, were lower than 15 % for all analytes. The validated method was used to assess DPZ biotransformation by the fungi Beauveria bassiana American Type Culture Collection (ATCC) 7159 and Cunninghamella elegans ATCC 10028B. Using the fungus B. bassiana ATCC 7159, a predominant formation of (R)-5-ODD was observed while for the fungus C. elegans ATCC 10028B, DPZ was biotransformed to (R)-6-ODD with an enantiomeric excess of 100 %.
Assuntos
Beauveria/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Cunninghamella/metabolismo , Indanos/metabolismo , Piperidinas/metabolismo , Biotransformação , Meios de Cultura/metabolismo , Donepezila , Indanos/química , Estrutura Molecular , Piperidinas/química , EstereoisomerismoRESUMO
Zopiclone, zolpidem and zaleplon (Z-drugs) are nonbenzodiazepine hypnotic drugs that are used for the treatment of insomnia. These drugs were developed with the intent to overcome some disadvantages of benzodiazepines, such as dependence and next day sedation. In general, the nonbenzodiazepine hypnotic drugs are administered in oral doses daily and are widely biotransformed in the body. A large number of analytical methods based on chromatographic and electrophoretic techniques for the quantification of Z-drugs and their metabolites in biological matrices have been reported. In this review, the bioanalytical methods for Z-drugs were reviewed with the focus placed on sample preparation procedures and the separation techniques used. Furthermore, as these drugs are also reported as drugs of abuse or in drug-facilitated crime, screening methods that simultaneously cover these drugs and also other drugs of abuse were included in this review.
Assuntos
Acetamidas/análise , Compostos Azabicíclicos/análise , Hipnóticos e Sedativos/análise , Piperazinas/análise , Piridinas/análise , Pirimidinas/análise , Acetamidas/uso terapêutico , Compostos Azabicíclicos/uso terapêutico , Cromatografia Líquida de Alta Pressão , Eletroforese Capilar , Humanos , Hipnóticos e Sedativos/uso terapêutico , Espectrometria de Massas , Piperazinas/uso terapêutico , Piridinas/uso terapêutico , Pirimidinas/uso terapêutico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , ZolpidemRESUMO
This study evaluated the release of glutaraldehyde from heat-polymerized acrylic resins subjected to disinfection followed by chemical and mechanical polishing. Ninety disc-shaped specimens (15 x 4 mm), 30 per resin (Lucitone 550, QC-20 and Classico), were made and assigned to 2 groups according to the type of polishing. One side of each specimen was not polished and the other was either mechanically (n = 45) or chemically (n = 45) polished, and immersed in water at 50 °C for 1 h to allow the release of intrinsic substances and then kept in distilled water for 7 days. The specimens were disinfected by immersion in 2% glutaraldehyde for 10 min. After this period, 3 specimens from each group were immersed in water for 15, 30, 60, 120 and 240 min. For the 15-, 30-, 60-min immersions, 4 water exchanges were done at the end of period. High performance liquid chromatography (HPLC) was used to detect and quantify the glutaraldehyde released after each period. Data were analyzed statistically by two-way ANOVA and multiple comparisons were done by Tukey's and Scheffé's tests (α = 0.05). No glutaraldehyde release was observed from the specimens with chemical polishing at any of the immersion periods, while the mechanically polished specimens released glutaraldehyde. In the groups with water exchanges, Lucitone released more disinfectant in the 15-min period (0.040 µg/mL), Classico in the 30-min (0.021 µg/mL) and 60-min (0.018 µg/mL) periods, and QC-20 the same amount (-1.760 µg/mL) in all periods. In the groups without water exchanges, Lucitone released the highest amount of disinfectant (-1.370 µg/mL), differing significantly from QC-20 (0022 g/mL) and Classico (0019 g/mL), which were similar. The findings of this showed that chemically polished specimens from the 3 resin brands did not release glutaraldehyde after different periods of immersion, while glutaraldehyde release was observed from the mechanically polished specimens, especially from those made of Lucitone resin.