Development and validation of a method for the assay and dissolution of a fixed dose combination of lamivudine, tenofovir and efavirenz tablet

Abstract

ABSTRACT A reverse phase-high performance liquid chromatographic method was developed and validated for the simultaneous determination of lamivudine, tenofovir disoproxil fumarate and efavirenz in lamivudine, tenofovir and efavirenz finished formulation product. The method was developed by altering various organic solvents such as acetonitrile and methanol, column, detection, flow rate and temperature. An isocratic elution mode with a mixture of acetonitrile and water in the ratio of (55:45 % v/v) was selected for the mobile phase with a nucleosil (Macherey Nagel-Germany) C18 (4.6 mm x 250 mm x 5m) column as stationary phase for simultaneous separation of lamivudine, tenofovir disoproxil fumarate and efavirenz. The separation was achieved at a flow rate of 1 mL/min and detection wavelength of 252 nm at room temperature. Further, different dissolution media were investigated for optimal release of lamivudine, tenofovir disoproxil fumarate and efavirenz from lamivudine, tenofovir and efavirenz tablets. The optimization of dissolution medium was preceded by establishment of the sink concentration for efavirenz which was found at 0.5% sodium dodecyl sulphate in water with a release of more than 75% of each of the three active pharmaceutical ingredients at 37°C with a paddle method, 75 rpm at 45 min. The analytical method was validated and the linear range was found in the concentration range of 0.05 to 0.12 mg/mL of lamivudine, tenofovir disoproxil fumarate and efavirenz with regression coefficient (r2) of 0.9984 which met the acceptance criteria of r2 equal or greater than 0.98. The % rsd for the intra-day precision were 1.08%, 1.23% and 1.46% for lamivudine, tenofovir disoproxil fumarate and efavirenz respectively. The % rsd for the inter-day precision were 1.95%, 1.99% and 1.67% for lamivudine, tenofovir disoproxil fumarate and efavirenz respectively. The test method had an acceptable level of accuracy for the assay of lamivudine, tenofovir disoproxil fumarate and efavirenz in lamivudine, tenofovir and efavirenz tablets from 50 % to 120 % of test concentration with % rsd less than 2% for all three active pharmaceutical ingredients. The test solution remained stable when stored at 4°C for 72 hours. The method was robust as it remained largely unaffected by small variations in temperature and mobile phase. All of these assessed parameters complied with the acceptance criteria hence indicated the usefulness of the reverse phase-high performance liquid chromatographic method for determination of assay and dissolution release testing for finished formulation product which contain lamivudine, tenofovir disoproxil fumarate and efavirenz active substances.