Desenvolvimento de métodos analíticos para quantificação de efavirenz, lamivudina e fumarato de tenofovir desoproxila em comprimidos de dose fixa combinada e em plasma

Abstract

Antiretroviral therapy for human immunodeficiency virus infections usually consists of the combination of at least three antiretroviral drugs, therapeutic strategy known as highly active antiretroviral therapy. In recent studies, efavirenz, lamivudine and tenofovir disoproxil fumarate proved to be virologically and immunologically effective, well tolerated and safe. Tablets containing efavirenz (66 mg), lamivudine (33 mg) and tenofovir disoproxil fumarate (33 mg) fixed-dose combination were prepared in Fundação Ezequiel Dias considering the conversion of the human therapeutic dose for rabbits and were subjected to quality control tests. The wet granulation process was used in the production of tablets, due to the low density and fluidity of efavirenz in micronized form. The tablets complied with pharmacopoeial requirements for weight variation, friability, assay, uniformity of content and disintegration time. In this work, an analytical method was developed and validated for simultaneous quantification of efavirenz, lamivudine and tenofovir disoproxil fumarate in a fixed-dose combination tablet. Analysis by reverse phase HPLC with a gradient mobile phase (buffer pH 5.4 and methanol) and detection at ë 260 nm was efficient in the separation and quantification of this antiretrovirals. The developed method showed to be selective, linear, precise, accurate and robust and can be successfully used in for routine quality control analyses. A bioanalytical method by HPLC with detection by mass spectrometry and electrospray ionization in the positive mode was development for the quantification of efavirenz, lamivudine and tenofovir in human plasma. For the extraction of the drugs from plasma, protein precipitation and internal standards were employed. The chromatographic analysis was performed using a cyano columm with a gradient mobile phase (formic acid 0.05% and methanol). The method showed to be linear (from 200 to 10000 ng/mL for efavirenz, from 50 a 4000 ng/mL for lamivudina and from 100 to 1000 ng/mL for tenofovir), precise, accurate and showed no residual and matrix effects. The bioanalytical method development can be applied for bioavailability and bioequivalence studies as well as in the therapeutic monitoring of patients treated with the combination antiretroviral of efavirenz, lamivudina and tenofovir disoproxil fumarato.