RESUMO
Low dietary calcium intake and absorption may increase the risk of hypocalcaemia disease states. Reducing the particle size of calcium-containing powders and increasing the specific surface area (SSA), may have high oral calcium bioavailability. The absorption of a single dose of different sized calcium carbonate nanoparticles was traced in Sprague-Dawley rats with radioactive calcium-45 (half-life = 162.6 days, ß- endpoint = 258 keV; 100%). Four calcium carbonate formulations (calcium-45) were administered to Sprague-Dawley rodents (6 per treatment; n = 24). The groups were [45Ca]CaCO3 SSA 3 m2/g, [45Ca]CaCO3 36 m2/g, [45Ca]CaCO3 64 m2/g and a separate [45Ca]CaCO3 36 m2/g formulation produced by flame assisted pyrolysis. Blood and urine were sampled periodically, and organs collected and analysed after euthanasia. No changes in SSA or crystallinity were observed when powders before or after irradiation were compared. The [45Ca]CaCO3 64 m2/g formulation presented with higher levels in blood 2 h after administration and a higher liver and femur concentration. These findings suggest [45Ca]CaCO3 64 m2/g could lead to increased oral bioavailability.
