Comparative studies of the kinetics of dissolution of medicines on the basis of clopidogrel

Abstract

Generic medicines occupy dominant positions both in the pharmaceutical market of Ukraine and in industrial production by domestic pharmaceutical enterprises. The use of generic drugs in medical practice is of significant medical and social importance for expanding the accessibility of the general population to essential drugs. In Ukraine, more than twenty generic medicines based on clopidogrel, both foreign and domestic, are registered. All generic drugs containing clopidogrel bisulfate must comply with pharmaceutical bisulfate must comply with pharmaceutical equivalence, the kinetics of release of the active pharmaceutical ingredient using the Dissolution test in vitro, and pharmacokinetic parameters in vivo.
 The aim of the work was to carry out comparative studies of the dissolution kinetics of four samples of generic drugs based on clopidogrel with the dissolution kinetics of the original drug Plavix®, to evaluate the similarity factor of dissolution profiles and to determine the effect of biopharmaceutical factors on the equivalence of generics. Comparative studies of the kinetics of dissolution were carried out by the in vitro method according to the «Dissolution» test using a device with a blade with a
 rotation speed of 50 rpm, a dissolution medium with a pH value of 2.0 in a volume of 900 ml at a temperature of 37 ± 1 °C. The determination of the quantitative content of clopidogrel, which passed into the dissolution medium, was carried out by the method of adsorption spectrophotometry in the ultraviolet region at a wavelength of
 about 240 ± 2 nm. Based on the data obtained, the dissolution profiles of the original drug Plavix® and the studied samples of generic drugs were constructed, the similarity of which was assessed by the value of the similarity factor. According to the research results, it was found that one sample of the generic drug proved its equivalence by the in vitro method to Plavix®, and three other samples of generics had differences in dissolution kinetics in comparison with the original drug. Biopharmaceutical factors were analyzed that could affect the dissolution kinetics of the studied generic drugs, from which the physicochemical characteristics of clopidogrel bisulfate, the qualitative and quantitative composition of excipients and the features of the technological process were determined.
 Thus, on the basis of the comparative studies of the dissolution kinetics of drugs based on clopidogrel, generics were found that did not correspond to the in vitro equivalence according to the Dissolution test to the original drug, which could be due to the influence of a combination of biopharmaceutical factors.