Green HPLC quantification method of lamivudine, zidovudine and nevirapine with identification of related substances in tablets

A green HPLC method for lamivudine (3TC), zidovudine (AZT) and nevirapine (NVP) determination in fixed-dose combination tablets was developed using ethanol as both one of the mobile phases and the solvent for sample preparation. This method was validated according to ICH Q2(R1) guideline. Additionally, the method was adapted to complete the analysis of five related substances described in the International Pharmacopoeia (Ph. Int.), five other known related substances and two excipients. The separation was obtained with a C18 column (ARV4 5 µm 250 × 3.0 mm, Interchim) using a gradient mode with 0.1M ammonium acetate buffer (pH 4.5) and ethanol as mobile phase at 35°C, a flow rate of 0.4 mL/min, at 270 nm and an injection volume of 10 µL. The combination of ethanol (biodegradable and low-cost alternative solvent) with the use of a column diameter of 3 mm instead of 4.6 mm as used in pharmacopoeias, makes the wastes of the analysis more environmentally friendly and allows the use of a conventional HPLC pump (