Dissolution Profile of Calcium Supplements in Brazil: A Critical Analysis and Formulation Proposal

Low calcium intake is common worldwide and may lead to osteoporosis. Therefore, calcium supplementation is a vital resource to prevent fractures in patients with osteoporosis. The present study aims to assess whether the dissolution profiles of calcium tablets available in the Brazilian pharmaceutical market are equivalent and interchangeable. Seven commercial samples from the local pharmaceutical market and an experimental formulation containing calcium carbonate from seaweed Lithothamnium calcareum were evaluated. In addition to the dissolution test, the tablets were characterized according to average weight, hardness, disintegration time, and calcium content. Moreover, we determined the polymorphic forms of calcium present in the tablets by employing x-ray diffraction. We related the data of these quality attributes by applying principal component analysis (PCA). The results revealed that the formulation containing calcium carbonate from the seaweed L. calcareum outperformed the other products from the market, with a complete dissolution within 10 min. Statistically significant differences in dissolution efficiency were noted. The disintegration times for all samples varied greatly from 12 s to 14 min. Polymorphic forms were identified in two samples, and the calcium content of the commercial samples was out of pharmacopeial specification. Thus, the products cannot be considered equivalent. It is recommended to evaluate the manufacturing processes for these supplements.