In vitro – In vivo Correlation : Dissolution Profile and Pharmacokinetic of Calcium Carbonate Tablets Marketed in Yemen

Abstract

The study aimed to validate an indirect colorimetric based on a classical approach for evaluating the in-vitro/ in-vivo correlation of calcium carbonate tablets marketed in Yemen. The colorimetric was validated and used to determine calcium concentration in different brands of tablets and body, calcium dissolution testing in vitro (IV), and pharmacokinetic in vivo (IV) through blood samples of 18 healthy male volunteers. On the other hand, IV/ IV correlation was estimated in this study. The results showed that the photometric method was precise (RSD: 1.27%) and accurate (mean recovery: 100.17%). The study proved the poor quality of generic products marketed in Yemen, which could be attributed to bad pharmaceutical manufacturing and the absence of efficient regulatory systems. Also, this method was instead of the atomic spectrophotometer method required by USP monographs for the assay of calcium dissolution testing.  The similarity factor (f2) and mechanism release in vitro of generic versus original calcium products were affected by different manufacturing processes, and this was clear in this study.   In addition, the results proved that the bioequivalence of generic products versus original products was not available (IV/IV correlation was not available for all products). Poor quality of some products marketed in Yemen may affect the efforts to control hypocalcemia, and providing high-quality drug products will significantly reduce diseases. Non–linear IV/ IV correlations were established between various dissolution and bioavailability parameters for three commercial brands of calcium tablets using a level A  IV/IV correlation approach. Therefore, with proper standardization of assessment methods, in vitro dissolution parameters can predict the bioavailability of these calcium tablets marketed in Yemen.