COMPARATIVE STUDY OF RP-HPLC METHOD VERSUS FOURIER TRANSFORM CONVOLUTION CHEMOMETRIC METHODS; AN APPLICATION ON PHARMACEUTICAL BINARY MIXTURES OF CANDESARTAN CILEXETIL-PITAVASTATIN CALCIUM AND CLOPIDOGREL BISULFATE-ROSUVASTATIN CALCIUM

Abstract

Objective: A comparative study of smart spectrophotometric chemometric assisted techniques and RP-HPLC for the determination of candesartan cilexetil (CAN)-pitavastatin calcium (PIT) and clopidogrel bisulfate (CLO)-rosuvastatin calcium (ROS), binary co-administered drugs were developed and validated.

Methods: The spectrophotometric chemometric assisted methods included two simple techniques, namely Fourier transform convolution (FF) and ratio spectra of Fourier transform convolution (FFR) methods. FFR is considered as a hybrid divisor ratio spectra method where Fourier functions are applied to divisor ratio signals. The RP-HPLC method involves a rapid separation on a C₁₈ column using a mobile phase consisting of acetonitrile: sodium dihydrogen phosphate (adjusted to pH 2.6 using orthophosphoric acid) in the ratio of 70:30 v/v at a flow rate of 1 ml/min in isocratic mode. CLO and ROS were monitored at 220 nm however CAN and PIT were monitored at 238 nm.

Results: The spectrophotometric chemometric assisted methods proved their ability to quantify each of the studied drugs in their binary mixtures, where excellent percentage recoveries were obtained. FF and FFR method proved to be linear over the concentration range of 10-50 µg/ml for CLO, 4-20 µg/ml for ROS, 8-20 µg/ml for CAN and 2-10 µg/ml for PIT. The RP-HPLC method was able to separate the drugs in the study; retention times were found to be 3.9 min and 14.4 min for ROS-CLO, 4.2 min and 14.5 min for PIT-CAN respectively. The RP-HPLC method was found to be linear in the concentration range of 0.1-0.5 µg/ml for CLO, 0.04-0.2 µg/ml for ROS, 0.5-1 µg/ml for CAN and 0.05-0.1 µg/ml for PIT. System suitability parameters proved that peaks were well resolved from each other.

Conclusion: The spectrophotometric and chromatographic methods were validated according to ICH guidelines. Recovery was found to be in the range of 95.9 %-100.5 % in synthetic laboratory mixtures. The suggested spectrophotometric methods have the advantage over other methods that they do not require a preliminary separation. Statistical analysis between the suggested spectrophotometric chemometric assisted and RP-HPLC methods, using student's t-and F-test revealed that there is no difference between the applied methods.