Validated Stability-Indicating RP-HPLC Method for the Dual-Drug Analysis of Fluconazole and Terbinafine in Solid Oral Dosage Forms

An efficient and cost-effective RP-HPLC method was optimized for the concurrent quantification of fluconazole and terbinafine in combined tablet formulations. Separation was accomplished on a Discovery C18 column (150 × 4.6mm, 5μm) using a mobile phase comprising 0.01N sodium hydrogen phosphate buffer and acetonitrile (70:30 v/v), delivered at 1.2mL/min under isothermal conditions (30°C). UV detection at 246nm yielded distinct retention times of 2.16 min for fluconazole and 3.09 min for terbinafine. The method demonstrated high precision (%RSD < 0.5), excellent recovery (99.69% for fluconazole and 100.15% for terbinafine), and low detection limits (0.52μg/mL and 0.17μg/mL, respectively). Linearity was confirmed with correlation coefficients exceeding 0.999. The rapid analysis and reduced solvent consumption render this method highly suitable for routine quality control in pharmaceutical settings.