Simultaneous spectrophotometric estimation of aceclofenac and thiocolchicoside by first order derivative method in combined dosage form

The objective of the study was to develop a simple, accurate, precise and rapid a UV spectrophotometric i.e. first order derivative method for the determination of aceclofenac and thiocolchicoside in combined dosage form i.e. tablets by using methanol as a solvent. The method was further validated by ICH guidelines. The proposed first order derivative method involves the measurement of absorbance of one drug at zero crossing point of other; hence wavelengths 259 nm and 353.6 nm were selected for the estimation of aceclofenac and thiocolchicoside respectively. The linearity of the proposed method was found in the concentration range of 1 to 14 μg /ml (r2= 0.9995) for aceclofenac and 1 to 14 μg /ml (r2= 0.9999) for thiocolchicoside respectively. The percentage mean recovery was found to be 100.52 % for aceclofenac and 100.72% for thiocolchicoside and respectively. The method was also statistically validated for its linearity, accuracy and precision. Both intra and inter day variations showed less percentage (%) RSD values indicating high grade of precision of this method