In our study we observed difference in release in vitro of medicinal products containing moxonidines: none of the study drugs was fully similar to the reference drug in all media. At pH 6.8 similarity factors f2 for all study generic drugs were also less than 50 (23.8, 49.8, 38.6, and 35.9), so their dissolution curves were non-similar to that of reference drug. Similarity factors f2 were calculated 17.52 and 35.30, respectively (less than 50). However, in case of study drugs #1 and #4 significant differences were observed at a single time point (15 min), which suggests that their dissolution profiles are non-similar to that of the reference drug.

Similarly, at pH 4.5 dissolution profiles of study drugs #2 and #3 were similar to that of the reference drug, and the similarity factor f2 was not calculated. Within 15 min more that 85% of moxonidine dissolved from the reference drug and all study drugs at pH 1.2 dissolution profiles were similar without calculation of similarity factor f2. An high performance liquid chromatography method with ultraviolet detection at 220 nm was used to assay. The sampling for dissolved moxonidine was performed 5, 10, 15, 20, and 30 min after the test was started. The CDKT was performed in the media with the following pH: 1.2 (1:9 mixture of 0.1 M hydrochloric acid and water), 4.5 (acetate buffer solution, prepared as per State Pharmacopoeia, XIII), and 6.8 (phosphate buffer solution, prepared as per State Pharmacopoeia, XIII).

In vitro dissolution test of moxonidine from the study drugs was performed using comparative dissolution kinetics test (CDKT). Objects of the research were film-coated tablets containing moxonidine (INN) in a dose 0.4 mg: a reference drug Physiotens® and 4 generic drugs. Investigation of comparative dissolution kinetics of generic medicinal products containing moxonidine versus reference drug.

Comparative dissolution f2