DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR THE ESTIMATION OF ESCITALOPRAM OXALATE AND FLUPENTIXOL DIHYDROCHLORIDE IN COMBINED DOSAGE FORM AND PLASMA

Objective: The objective of the study was to develop a simple and rapid chromatographic method for quantification of escitalopram oxalate and flupentixol dihydrochloride in combined dosage form and plasma. Methods: The separation was achieved with a sun fire C8 [150×4.6 mm] 3.5 µm column with an isocratic mobile phase containing a mixture of potassium dihydrogen orthophosphate buffer: methanol: acetonitrile [30:60:10 v/v/v] pH adjusted to 11. The flow rate of the mobile phase was 1.5 ml/min with a Photodiode array [PDA] detection at 230 nm. Results: The HPLC method was developed and validated with respective linearity, accuracy, and precision, detection of limit, robustness, and specificity. The precision of the results stated as the relative standard deviation was below 2 %. The calibration curve was linear over a concentration range from 10-50 µg/ml for escitalopram oxalate and 1-5 µg/ml for flupentixol dihydrochloride with a correlation co-efficient 0.994 and 0.977 respectively. The accuracy of the method was demonstrated at levels in the range of 100 % and 120 % of the specification limit. The recovery of escitalopram oxalate and flupentixol dihydrochloride was found to be in the range of 90 % to 88 %, respectively. The lowest detection limits were found to be 2 µg/ml for escitalopram oxalate and 0.1 µg/ml for flupentixol dihydrochloride. The lowest quantification limits were found to be 5 µg/ml of escitalopram oxalate and 0.5 µg/ml of flupentixol dihydrochloride. Conclusion: The developed method was validated for linearity, accuracy, precision, the limit of detection and quantification, specificity. The method was applied successfully for the determination of escitalopram oxalate and flupentixol dihydrochloride in the combined dosage form and plasma