Development and validation of dissolution test for captopril in capsules by HPLC

Abstract

Captopril is an anti-hypertensive and vasodilator agent utilized in the congestive cardiac insufficiency and it can be commercially found in Brazil in the form of tablets and compounded capsules. The aim of this study was to evaluate the dissolution profile of captopril in capsules dosage obtained from compounded pharmacies, when submitted to different conditions of pH, apparatus, stirring speed of dissolution medium and analytical method, as well the validation of the dissolution procedure and of the method of analysis. The drug concentrations in dissolution medium were determined by liquid chromatography and ultraviolet spectrophotometric. The results showed that the chromatographic method was the most suitable for captopril capsules evaluation, while the spectrophometric method (recommended by the Brazilian and the United States Pharmacopeias) presented low specificity. The dissolution procedure in the selected conditions was precise, accurate and specific. The method was linear. With base in the results obtained the conditions of dissolution test for capsules were the use of 0.01 M HCl (900 mL, 37 ± 0.5 ºC), basket apparatus, stirring speed 50 rpm, 20 minutes time and quantification by chromatographic method. All the capsules presented satisfactory results in all the tests assessed.