Desenvolvimento e validaÃÃo de mÃtodos bionalÃticos para dosagem de antimicrobianos em plasma humano

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The Brazilian policy for generic drugs (Bill n 9.787, 10th of February, 1999) is improving the access to quality medicines by the Brazilian population. However, it makes it necessary to have analytical methods for the quantification of drugs in biological matrices with better selectivity and sensitivity for both drugs and metabolites so that they can be applied to comparative pharmacokinetics studies (bioequivalence). In Brazil there is still a scarcity of human resources with academic training for conducting comparative bioequivalence studies, especially for the analytical steps. With the purpose of helping to implement this policy, the present work had the aim of develop and validate analytical methods to quantify two classes of antibiotics (sulphonamides and fluoroquinolones) in human plasma and to apply these methods to the biopharmaceutical evaluation of different formulations of these drugs. During the development of the methods, the complexity of the techniques used increased from liquid-liquid extraction (LLE) with UV detection (HPLC-UV) through solid phase extraction (SPE) with HPLC-UV and also solid phase extraction with detection using tandem mass spectrometry (HPLC-ESI MS/MS). The development and validation of bionalytical methods encompass the selection of the chromatographic systems and the detection strategy, extraction technique for sample clean-up so that quality chromatograms are obtained, stability studies in the biological matrix, and the compliance with system suitability and quality control requirements for the chromatographic runs. Amongst the fluoroquinolones, the one selected for the study was norphloxacin (NFX) 400 mg tablets. For extraction and clean-up in human plasma we used LLE followed by quantification using HPLC with UV detection. Amidst the many sulphonamides, the one used in our study was a formulation of sulphametoxazole and trimetoprim (SMZ + TMP). We determine SMZ and TMP simultaneously in human plasma after administration of the formulations: hard gelatin capsules with 400mg + 80mg of SMZ and TMP respectively by offline SPE with quantification by HPLC-UV and a suspension 400mg + 80mg of SMZ and TMP/ 10mL) by HPLC-ESI-MS/MS. The bioavailability of the drugs in the formulations was evaluated through statistical analysis of plasma concentration data, using parameters such as area under curve (AUC) and maximum plasma concentration (Cmax) using the criteria set forward by the Brazilian Sanitary Agency â ANVISA (Bill RE 898, 29th, May, 2003). The methods proved to be linear, precise, accurate and rugged considering the high sample throughput. The HPLC-ESI-MS/MS method proved to be more rugged since it allowed a better clean-up of plasma interferents from the samples, and a shorter analysis time (2.5 min), decreasing the amount of solvent residue generated. All the methods developed were able to discriminate the comparative bioavailability of the formulations studied

ASSUNTO(S)

clae-uv ell bioequivalence sulphametoxazole + trimetoprim efs norfloxacino sulfametoxazol + trimetoprima lle hplc-ms/ms cl-em/em bioequivalÃncia spe norphloxacin hplc-uv farmacia

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