A HPLC method was developed to quantify thymine and thymidine impurities in stavudine bulk drug. The separation was carried out in isocratic mode using methanol/water (20:80) as mobile phase, a C18 column and UV detection at 266 nm. The method provided selectivity based on peak purities and resolution among peaks. It was linear over the range of 0.5-5.0 µg/mL. The quantitation limits were 0.021 µg/mL for thymine and 0.134 µg/mL for thymidine. The average accuracies of three concentrations ranged from 97.06 to 102.61% and precision was close to 1%. The method showed robustness, remaining unaffected by deliberate variations in relevant parameters.

A high performance liquid chromatography method was developed to quantify lamivudine, stavudine and nevirapine combined in tablets. The separation was carried out in less than 10 min using a phosphate buffer of pH 3.0 and acetonitrile (75:25, v/v) as mobile phase, a LiChrospher ODS column and UV detection at 266 nm. The method was linear over the range of 15-135 µg/mL (lamivudine), 4-36 µg/mL (stavudine) and 20-180 µg/mL (nevirapine). The accuracy ranged from 98.56 to 102.04% and intra-day and inter-day precision was less than 1% for the three drugs. The method showed robustness, remaining unaffected by deliberate variations in relevant parameters.

A lamivudina é um fármaco indicado para o tratamento de infecção por HIV, tipos 1 e 2. Tem sido extensivamente utilizada no Brasil, em programa público do Ministério da Saúde. Visando à verificação da qualidade dos medicamentos contendo este fármaco foi estabelecida e validada metodologia para determinação do teor da lamivudina. Foi também realizado estudo de equivalência farmacêutica frente ao medicamento referência. Parâmetros físicos e físico-químicos de comprimidos de liberação imediata de diferentes lotes de quatro laboratórios (G, A, B e C) foram avaliados. O método proposto para o doseamento, por cromatografia líquida de alta eficiência, mostrou precisão, exatidão, linearidade e especificidade. Os lotes dos laboratórios G, A e B apresentaram resultados adequados em todos os testes aos quais foram submetidos. O produto G (referência) mostrou similaridade entre seus lotes com dissolução rápida. Os produtos A e B mostraram diferenças entre seus lotes, mas ao final do tempo determinado alcançaram cedência semelhante ao do produto G, sendo considerados equivalentes farmacêuticos ao medicamento referência. Os lotes do produto C não foram similares entre si e apresentaram baixa dissolução, não possuindo qualidade adequada para o consumo humano.

Lamivudine is a drug used in the treatment of types 1 and 2 HIV infections. It has been widely used in Brazil, in public programs of the Health Ministry. This work reports lamivudine assay methodologies, which have been developed and validated. Pharmaceutical equivalency studies were also performed for lamivudine tablets. Physical and physicochemical parameters of immediate release reference and test tablets of four different laboratories (G, A, B and C) were evaluated. The proposed analytical method, high performance liquid chromatography, presented satisfactory precision, accuracy, linearity and specificity. Batches from laboratories G, A and B showed appropriate results in all tests to which they were submitted. Tablet batches from laboratory G (reference) showed similar dissolution profile and fast dissolution rate. The products A and B showed differences between their batches, in regards to the dissolution rates at the initial profile. However at the end of the profile they reached similar release to the reference, product G. Therefore they can be considered pharmaceutical equivalents to the reference product. Batches of product from laboratory C showed much more differences with reduced dissolution presenting no appropriate quality for human consumption.