IN VITRO EQUIVALENCE EVALUATION OF MEDICINES WHICH CONTAINE MAGNESIUM SALTS AND VITAMIN B6
DOI:
https://doi.org/10.11603/2312-0967.2026.2.16359Keywords:
magnesium, pyridoxine hydrochloride, dissolution test, dissolution profile, similarity factor, medicine, in vitro equivalenceAbstract
The aim of the work is to investigate the dissolution profiles of magnesium and pyridoxine hydrochloride from tablet dosage forms, and perform a comparative evaluation of their similarity by using the similarity factor (f2).
Materials and Methods. The study was conducted using an in vitro method with the dissolution test in media having different pH values (1.0, 1.2, 4.5, 6.8), simulating the conditions of the gastrointestinal tract. The magnesium content was determined by complexonometric titration, while pyridoxine hydrochloride was determined spectrophotometrically. The similarity factor (f2) was used to compare the dissolution profiles.
Results and Discussion. The release of magnesium from the tested formulations was found to be markedly pH-dependent. In acidic media (pH 1.0 and 1.2), intense dissolution occurred, with the release exceeding 75% at 30 minutes and reaching > 90% at 45 minutes, thereby meeting the acceptance criteria for immediate-release solid dosage forms. At higher pH values (4.5 and 6.8) the dissolution rate decreased due to the lower solubility of magnesium compounds under less acidic conditions. Pyridoxine hydrochloride exhibited rapid and virtually complete release at the earliest sampling points, independent of the pH of the dissolution medium. This indicates the high aqueous solubility of pyridoxine HCl and the absence of a significant effect of physical and chemical medium factors on its release behavior. The calculated similarity factor (f2) values exceeded 50 for all tested media, confirming the similarity of the dissolution profiles between the two medicines.
Conclusions. The dissolution profiles of the investigated tablet dosage forms were found to be similar based on the f2 value, thus confirming their in vitro equivalence. A clear pH-dependent effect on magnesium release was observed, whereas no such effect was noted for pyridoxine hydrochloride. The dissolution test proves to be an effective tool for quality evaluation and comparative analysis of fixed-dose combination drug products.
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