Development & determination of UV method for sildenafil & fluxetine in bulk drug & in formulation

A simple, rapid, precise and highly selective spectrophotometric method was developed for simultaneous estimation of Sildenafil citrate and Fluoxetine Hydrochloride in tablet dosage form. This method, involves the measurement of absorbances of Sildenafil citrate and Fluoxetine Hydrochloride at the wavelengths of 282nm (λmax of Sildenafil citrate) and 249 nm (λmax of Fluoxetine Hydrochloride). Methanol was used as solvent. Linearity was observed in the concentration range of 10-18µg/ml for Sildenafil citrate and 3-8ug/ml. Fluoxetine Hydrochloride. The accuracy of the method was confirmed by recovery studies of tablet dosage forms and was found to be 98.1% and 99.2% for Sildenafil citrate and Fluoxetine Hydrochloride respectively. The method showed good reproducibility and recovery with % RSD less than 2. Thus, the proposed method was found to be rapid, specific, precise, accurate and cost-effective quality control tool for the routine analysis of Sildenafil citrate and Fluoxetine Hydrochloride in bulk and combined dosage form. A rapid and simple derivative spectrophotometric method was developed for simultaneous determination of Sildenafil citrate and Fluoxetine Hydrochloride in tablet dosage form. This method involves second order derivative spectroscopy using 282 nm and 249 nm as zero crossing points for Sildenafil citrate and Fluoxetine Hydrochloride respectively in methanol. Linearity was observed in the concentration range of 10-18µg/ml for Sildenafil citrate and 3-8ug/ml for Fluoxetine Hydrochloride. The accuracy of the method was found to be 98.21% and 99.2% for Sildenafil citrate and Fluoxetine Hydrochloride respectively. The method showed good reproducibility and recovery with % RSD less than 2.Thus, the proposed method was found to be rapid, specific, precise, accurate and cost-effective quality control tool for the routine analysis of sildenafil citrate and Fluoxetine Hydrochloride in bulk and combined dosage form.                A selective, precise, isocratic and accurate stability indicating reverse phase high performance liquid chromatographic method was developed for the simultaneous determination of Sildenafil citrate and Fluoxetine Hydrochloride in the tablet dosage form. The method was validated for the linearity, accuracy, precision, robustness, system suitability as per ICH guidelines. Sildenafil citrate and Fluoxetine Hydrochloride were found to be linear in the range of 10-100 and 10-18µg/ml and 3-8ug/ml with the recoveries of 98.6% and 99.2%. The method was also applied for the determination of sildenafil citrate and Fluoxetine Hydrochloride in the presence of their degradation products formed under variety of stress conditions.