Elucidating the effect of specific surface area on the gastrointestinal absorption of nanostructured calcium through Calcium-45 in vivo radiotracing. (July 2021)

• Record Type: Journal Article
• Authors: Kleynhans, Janke; Cloete, Theunis; Dunn, Henri C.; Posavec, Lidija; Grobler, Anne F.; Zimmermann, Michael B.; Zeevaart, Jan Rijn
• Is Part Of: Applied radiation and isotopes. Volume 173(2021)
• Publication Date: 2021-07
• Subjects: Nanoparticles -- Flame-assisted pyrolysis (FASP) -- Calcium carbonate -- Hypocalcemia; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2021.109702
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: 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, β − endpoint = 258 keV; 100%). Four calcium carbonate formulations (calcium-45) were administered to Sprague-Dawley rodents (6 per treatment; n = 24). The groups were [ 45 Ca]CaCO3 SSA 3 m 2 /g, [ 45 Ca]CaCO3 36 m 2 /g, [ 45 Ca]CaCO3 64 m 2 /g and a separate [ 45 Ca]CaCO3 36 m 2 /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 [ 45 Ca]CaCO3 64 m 2 /g formulation presented with higher levels in blood 2 h after administration and a higher liver and femur concentration. These findings suggest [ 45 Ca]CaCO3 64 m 2 /g could lead to increased oral bioavailability. Graphical abstract: Image 1 Highlights: An SSA of 64 m 2 /g for calcium carbonate might be an optimal formulation of calcium. SSA 64 m 2 /g [ 45 Ca]CaCO3 demonstrated clear increased absorption and excretion compared to the other sizes. SSA 64 m 2 /g [ 45 Ca]CaCO3 accumulated in higher concentration in bone, as represented by the femur.