Concerns regarding Calcium Carbonate as an alternative Excipient for Titanium Dioxide

Titanium dioxide (TiO2) is widely used in pharmaceutical film coatings and capsule shells, with its white color and opacity used to improve the appearance of drug products and enhance the chemical stability of certain drugs. The European Commission banned the use of TiO2 in foods in Europe and the ban may be extend to include pharmaceutical products. Calcium carbonate (CaCO3) is an excipient that is being used as an alternative to TiO2 in the nutraceutical/dietary supplement industry. This excipient, however, is a basic compound that has the potential to affect drug stability. Moreover, the calcium in the calcium carbonate can complex with certain drugs. This paper considers these two issues and proposes that both compatibility and bioavailability studies may be needed when replacing TiO2 in pharmaceutical products with calcium carbonate.