DEVELOPMENT AND VALIDATION OF A STABILITY INDICATING LIQUID CHROMATOGRAPHIC METHOD FOR THE SIMULTANEOUS ESTIMATION OF PAROXETINE AND CLONAZEPAM IN BULK AND ITS PHARMACEUTICAL FORMULATIONS

A novel stability indicating reversed-phase liquid chromatographic method has been developed and validated for simultaneous estimation of paroxetine and clonazepam in combined pharmaceutical dosage form. An Agilent zorbax sb-c18 (250mmx4.6mmx5 µm) column with the mobile phase containing 0.2 % Orthophosphoric acid and Methanol (60:40 v/v) was used. The flow rate was maintained at 0.8 ml/min, column temperature was 30°C and effluents were monitored by using a photodiode array detector at 270 nm. The retention times of paroxetine and clonazepam were found to be 3.478min and 3.964 min, respectively. Correlation co-efficient for paroxetine and clonazepam were found to be 0.99 and 0.99, respectively. The proposed method was validated with respect to linearity, accuracy, precision, specificity, and robustness. Recovery of paroxetine and clonazepam in formulations was found to be in a range of 97-103% and 97-103% respectively. Paroxetine and clonazepam were also subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from and peak purity test results confirmed that paroxetine and clonazepam peaks were homogenous and pure in all stress samples, thus proving stability-indicating power of the method. Due to its simplicity, rapidness and high precision, this method can be applied for regular analysis