Matrix tablets, Guar gum, Oxaliplatin, Diclofenac sodium, Colorectal cancer, controlled release.

An accurate, precise and reproducible high performance liquid chromatographic method was developed for the simultaneous estimation of lamivudine, zidovudine and nevirapine in pharmaceutical dosage forms. Phenomenex C18 column (250 x 4.6 mm; 5µ) was employed for the separation of drugs. A mixture of 0.02 M trichloroacetic acid (6.8 pH) and methanol in the ratio of 40:60 v/v was used as the mobile phase and pumped at a flow rate of 1ml/min. The detection wavelength was set at 265 nm. The linearity of quantification was observed in the range of 7.5-112.5, 10-150 and 15-225 μg/ml for lamivudine, zidovudine and nevirapine respectively. The proposed method was validated according to ICH guidelines. The method was found to be suitable for simultaneous and accurate determination of these drugs in tablet dosage forms without any interference from the excipients.