RESUMO
The development of a specific agar diffusion bioassay for the quantitative determination of fluconazole formulated in capsules was carried out using a strain of Candida albicans ATCC 18804 as the test organism. A prospective validation of the method showed adequate linearity (r²=0.9995), precision (R.S.D. = 4.0 percent for intra-day and 4.5 percent for inter-day precision) and accuracy (mean recovery = 102.9 percent). High performance liquid chromatography was chosen as a comparison method for the fluconazole determination. The contents of fluconazole determined by both methods, for four capsule samples, showed a strong correlation, confirmed by Pearson's correlation coefficient value (r = 0.9884). The bioassay is a suitable method for both research and pharmaceutical industry laboratories.
Este trabalho visou ao desenvolvimento e validação de um método microbiológico por difusão em ágar para quantificação de fluconazol em cápsulas utilizando o isolado Candida albicans ATCC 18804 como reagente biológico. O método foi validado e foi verificada linearidade (r²=0,9995), precisão (D.P.R. = 4.0 por cento para precisão intra-dia e 4,5 por cento para precisão inter-dia) e exatidão (recuperação média = 102,9 por cento). Concomitantemente, foi realizado o doseamento de fluconazol nas cápsulas por meio de cromatografia líquida de alta eficiência. Os teores encontrados por ambos os métodos demonstraram alta correlação, confirmada pelo Coeficiente de Correlação de Pearson (r = 0,9884). O ensaio microbiológico desenvolvido pode ser considerado ferramenta valiosa tanto para a pesquisa científica quanto para a rotina da indústria farmacêutica.
Assuntos
Bioensaio/métodos , Cromatografia Líquida de Alta Pressão , Fluconazol/farmacocinética , Análise Espectral , Técnicas Microbiológicas/métodos , Cápsulas/análise , Cápsulas/farmacocinéticaRESUMO
The development and validation of an HPLC-UV method and a microbiological assay were performed for the analysis of ketoconazole in capsule formulations. The bioassay was developed using a specific agar diffusion technique with the strain of Candida albicans ATCC 18804 as the test organism. The effect of the mobile phase pH in the range of 2.5-7.5 on the retention and tailing factors of the ketoconazole peak was analyzed in the chromatography method and a pH value of 4.5 was considered to be adequate. A prospective validation of both methods showed adequate linearity (r2 > 0.99 for the two methods), precision, (RSD = 2.42% for intraday and 2.69% for interday precision for bioassay; RSD = 0.74% for intraday and 0.66% for interday precision for HPLC-UV), and accuracy (mean recoveries were 103 +/- 1.0% for bioassay and 99 +/- 1.0% for HPLC-UV). Student's t-test revealed no significant difference between the results obtained by the two methods (P < 0.05). The contents found for three capsule samples showed a strong correlation, as attested by Pearson's coefficient value (r = 0.9998), which also evidenced the concordance between the studied methodologies.
