SYSTEMATIC HPLC STUDY OF A NEW SERIES OF 4-METHYL-1,4-DIHYDROPYRIDINES WITH ANTITHROMBOTIC ACTIVITY

A systematic study of a new series of 4-methyl-1,4-dihydropyridine der ivatives by HPLC by both photodiode array and electrochemical detector s is reported. The optimum mobile phase was acetonitrile/ 0.05 M phosp hate buffer pH 3 (55/45, v/v) at a flow-rate of 1.5 mL/min. Compounds I-VIII were determined with UV detection at 250 nm and by electrochemi cal detection at + 1200 mV. Retention times varied between 3.0 and 14. 0 minutes in the optimal experimental conditions. Good linear relation ships between the peak areas and concentration were found, with limits of quantification ranging between 1 x 10(-8) M and 1 x 10(-6) M. Repe atability studies showed average variation coefficients lower than 1% for a photodiode array detector. No significant differences between th e detectors in sensitivity and selectivity were found. Also, we used d ifferent degradation trials to test the selectivity of the methods. Re sults of these experiments revealed that the developed methods exhibit ed a good selectivity.