Control Study of Captopril Degradation on Tablets by High Performance Liquid Chromatography Analysis

This work proposes a critical alteration in the official methods using high performance liquid chromatography (HPLC) to quantify the active pharmaceutical ingredient captopril and its major degradation product, captopril disulfide, present in captopril tablets. Analytical alternatives were studied to minimize captopril oxidative degradation for a 24-hour period in order to ensure sample solution stability and thereafter the analytical data reliability. Captopril degradation in solution is discussed in detail in this article. Six captopril 25 mg tablets commercial batches were used in this study. The analytical method was based on the official methods described in the Brazilian Pharmacopoeia 5th edition and The United States Pharmacopeia 36th edition (USP 36). For the analytical method development, a comparative stability study of captopril tablet commercial batches sample solutions was carried out within a 24-hour period using three different solvents to evaluate sample diluent solution better stability. The results demonstrate that samples prepared in methanol presented the best stability performance within the period studied unlike the samples prepared in diluent system described in the official product monographs.