PHARMACOKINETICS OF CALCIUM FROM CALCIUM SUPPLEMENTS IN HEALTHY VOLUNTEERS

Calcium supplementation is widely used in deficiency status and as an adjuvant in the treatment of osteoporosis. The objective of this study was to compare the oral bioavailability of calcium from tablets containing calcium fumarate to that of calcium gluconate. Twelve healthy volunteers participated in the study. Single-dose, two-treatment, two-sequence-crossover, randomized design test methodology was applied. The tablets were prepared by direct compression and were subjected to tests: drug content, hardness, friability, disintegration time and in vitro dissolution studies. The preparations were compared using pharmacokinetic parameters such as the area under the plasma concentration – time curve AUC(0-11), peak plasma concentration Cmax, time to reach maximum plasma concentration Tmax. No statistically significant difference was observed for any of the parameters, and the 90% confidence intervals calculated for the ratio of the logarithmically transformed AUC(0-11) values of both formulations were within the bioequivalence limit of 0.80-1.25. It can be concluded that the two tablet preparations of calcium are likely to be bioequivalent.