Desenvolvimento e Validação de Método de Dissolução de Suspensões de Benzoilmetronidazol e Perfil de Dissolução

Abstract

The benzoylmetronidazole is an insoluble ester of metronidazole, and it is indicated for the treatment of infectious disease caused by anaerobic bacteria and protozoa. This drug shows two potential degradation products, such as metronidazole and benzoic acid. Nowadays, there is no official monograph described for benzoylmetronidazole oral suspension, and this drug can show problems for its dissolution that may to influence the drug oral bioavailability. In this study, a dissolution method for benzoylmetronidazole oral suspension was developed and validated. To develop the method, the dissolution profiles in different medium and stirring speed were evaluated. The best dissolution conditions were paddle at 50 rpm stirring speed, gastric fluid medium (without pepsin), which allowed differentiate the diverse suspensions. The method was validated and shown to be specific, linear, precise, accurate and robust for the condition evaluated. A stability indicating method for the benzoylmetronidazole oral suspension by high performance liquid chromatography (HPLC) was developed and validated, and used for quantification of samples taken from the dissolution test. The conditions for the method were C18 (150 mm x 4,0 mm, 5 μm) column, mobile phase consisting of o-phosphoric acid 0,1% pH 3,0 and methanol (50:50 v/v) at a flow rate of 1,0 ml/min, using a isocratic elution. Benzoylmetronidazole was determined in the presence of degradation products using these analyses. The comparative dissolution profiles of benzoylmetronidazole oral suspensions were analyzed using the similarity factor, f 2 . The Weibull model describes the dissolution kinetics the suspensions in study. The dissolution method is suitable for routine quality control of benzoylmetronidazole oral suspensions and comparison of dissolution profiles of different commercial formulations.