Chemometric optimization of a RP-HPLC method for the simultaneous analysis of abacavir, lamivudine, and zidovudine in tablets

A method has been developed and validated for the separation of abacavir, lamivudine, and zidovudine by high-performance liquid chromatography (HPLC) on a C-18 column with uv detection at 270nm. The optimal conditions for separation were determined with the aid of a critical resolution map technique using the program DryLab(R). The effect of simultaneously varying the pH and proportion of methanol in the mobile phase was studied to optimize the separation. A response surface diagram was used to study the interaction between factors determining the separation. The mobile phase composition that provides an optimal resolution of components in an acceptable elution time is water: methanol (60:40 v/v) + 0.2% TEA and pH = 3.20 (pH adjusted with H3PO4). A method is applied for the analysis of Trizivir(R) tablets (Glaxo Wellcome, UK). The powdered tablets were extracted with methanol: water (50: 50 v/v) mixture and after addition of stavudine as an internal standard subjected to HPLC analysis and assayed by comparison of analyte to internal standard peak areas to concentration ratios.