Stability Indicating UV-Spectrophotometric Assay Of Terbinafine Hydrochloride In Dosage Forms

Two sensitive, precise and cost-effective UV-spectrophotometric methods are described for the determination of terbinafine hydrochloride (TFH) in bulk drug and tablets. The methods are based on the measurement of absorbance of TFH in 0.1M HCl at 222 nm in method A and in 0.1M acetic acid at 282 nm in method B. As per the International Conference on harmonization ICH guidelines, the methods were validated for linearity, accuracy, precision, limits of detection (LOD), limit of quantification (LOQ), robustness and ruggedness. Beer’s law is obeyed over the concentration ranges of 0.2-4.0 and 2.0-50.0 μg mL TFH in method A and method B, respectively, and the corresponding molar absorptivity values are 8.7 x 10 and 7.9 x 10 L mol cm. The proposed methods were applied successfully to the determination of TFH in tablets with good accuracy, precision and without any detectable interference from tablets excipients. The validity and reliability of the proposed methods were further assed by the recovery studies via a standard addition method. In addition, forced degradation of TFH was conducted in accordance with the ICH guidelines. Acidic, basic and water hydrolysis, thermal stress, peroxide and photolytic degradation were used to assess the stability indicating power of the methods. Slight degradation was observed during base degradation in method A and substantial degradation was observed during oxidative degradation in both methods. No degradation was observed under other stress conditions.