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 [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.

低膳食钙摄入和吸收可能会增加低钙血症疾病状态的风险。减小含钙粉末的粒径并增加比表面积（SSA），可能具有较高的口服钙生物利用度。使用放射性钙 45（半衰期 = 162.6 天，β ^-终点 = 258 keV；100%）在 Sprague-Dawley 大鼠中追踪单剂量不同尺寸碳酸钙纳米颗粒的吸收。将四种碳酸钙制剂 (calcium-45) 施用于 Sprague-Dawley 啮齿动物（每次治疗 6 只；n = 24）。各组为[ ⁴⁵ Ca]CaCO ₃ SSA 3 m ² /g、[ ⁴⁵ Ca]CaCO ₃ 36 m ² /g、[ ⁴⁵ Ca]CaCO₃ 64 m ² /g 和通过火焰辅助热解制备的单独的 [ ⁴⁵ Ca]CaCO ₃ 36 m ² /g 配方。定期对血液和尿液进行采样，并在安乐死后收集和分析器官。当比较辐射前后的粉末时，没有观察到 SSA 或结晶度的变化。[ ⁴⁵ Ca]CaCO ₃ 64 m ² /g 制剂在给药后 2 小时呈现出更高的血液水平以及更高的肝脏和股骨浓度。这些发现表明 [ ⁴⁵ Ca]CaCO ₃ 64 m ² /g 可以提高口服生物利用度。