DESENVOLVIMENTO E VALIDAÇÃO DE UM MÉTODO ESPECTROFOTOMÉTRICO PARA DETERMINAÇÃO DE DAPSONA EM FORMAS FARMACÊUTICAS SÓLIDAS

Abstract

The quality control is essential at all stages of production of a drug, once your goal is to verify that the product is in the standards required by the pharmacopoeias. One of the steps taken in this control is the quantification of dapsone in solid pharmaceutical forms, for this determination should be used analytical methodologies validated that generates information reliable and interpretable on the sample. Against the foregoing, this study aimed to develop and validate an analytical method for the determination of dapsone in solid pharmaceutical forms with spectrophotometric detection in the visible. The method is based on the reaction of the dapsone with nitrous acid, forming a diazo which reacts with the agent chromogenic 8- oxyquinoline in alkaline solution of NaOH, producing a compound of red color which absorbs strongly at 510 nm with molar absorptivity of 5.94x104 L mol-1 cm-1. The experimental parameters were carefully studied and optimized using the method the univariate. The analytical curve showed good linearity in the range of concentration of 1.62 x10-6 to 1,95 x 10-5 mol L-1 with correlation of 0.9998. The limits of detection and quantification were 7,05 x 10-8 mol L-1 and 2.35 x 10-7 mol L-1, respectively. For the study of the effect of matrix was used the method of standard addition, where the percentage of recovery was from 96.9 to 102.0%, which highlighted the fact that there was no interference from excipients used. The method was successfully applied to the determination of dapsone in two synthetic pharmaceutical formulations, which showed an error of -1.0 to +0.3, compared with the expected value and coefficient of variation of 0.6 and 1.0% for samples with 95% confidence interval.