ABSTRACT:
Two simple, rapid, accurate and economic spectrophotometric methods are described for the determination of Drotaverine Hydrochloride (DRO) and Diclofenac Potassium (DIC) in combined dosage form. The first method is First Derivative and second is Absorption Corrected method. The amplitudes at 248.92 nm and 242.64 in the first derivative spectra were selected to determine Drotaverine Hydrochloride (DRO) and Diclofenac Potassium (DIC), respectively in combined formulation. The second method was based on the absorption corrected method in which DRO and DIC exhibit ?max at 358.41 nm and 277.27 nm, respectively in double distilled water. DRO has some interference due to DIC at 277.27 nm, while DIC do not show any absorption at 358.41 nm. Quantitative estimation of DIC was carried out by subtracting the absorption due to DRO at 277.27 nm using experimentally calculated absorption factor. Beer’s law was obeyed in the concentration range of 8-40 µg mL-1 for DRO and 5-25 µg mL-1 for DIC for both the methods. The results of analysis have been validated statistically and recovery studies confirmed the accuracy and reproducibility of the proposed methods which were carried out by following ICH guidelines.