Desenvolvimento de métodos indicativos de estabilidade para nevirapina insumo farmacêutico ativo e comprimidos: propostas de caracterização estrutural e estudo de citotoxicidade para os produtos de degradação

Abstract

Stability is an important parameter for assessing the quality, safety and efficacy of active pharmaceutical ingredients (API) and drug products. The lack of stability can be related to loss of therapeutical effect and patient exposure to potential toxic effects from the degradation products. Nevirapine, which belongs to the class of nonnucleoside reverse transcriptase inhibitors, is an important component applied to Acquired Immunodeficiency Syndrome (AIDS) treatment. It is part of a worldwide recognized program of the Brazilian Ministry of Health, which justifies the importance of studying its stability by means of the forced degradation studies, the development of methods to evaluate the presence of degradation products in the API and the determination of the degradation profile of the drug. The API and nevirapine tablets were subjected to a detailed study of forced degradation, employing several degrading agents, which were used for the development of two selective stabilityindicating assay method by using ultra-high performance liquid chromatography with sub-2 µm and fused core columns , resulting in fast, efficient and with less expense of solvents methods. The stability-indicating assay method using fused core column was validated and proved to be selective for nevirapine and its degradation products, with resolution higher than 2.0 between the peaks and suitable peak purity for nevirapine. Calibration curves were linear in the range 8 to 48 g/mL, precise, accurate and robust for both nevirapine API as well as for the tablets, with a detection limit of less than 0.092 g/mL and a limit of quantification of less than 0.174 g/mL. Nevirapine was degraded in acidic and oxidative conditions and the degradation profile for tablets and API were similar. Chemical structures and mechanisms for the formation of three degradation products were proposed using the results obtained on a HPLC/MS-MS. The samples subjected to forced degradation in acidic and oxidative conditions presented no in vitro cytotoxicity against mononuclear cells from human peripheral blood of healthy individuals.