Preparation of calcium phosphate nanoparticles and evaluation of their effects on muscle cells of rat

Calcium phosphate has been used for many years as a DNA delivery system. It has not been approved for use in the vaccine adjuvant system since it has been known for site-specific reaction in the muscle cells for irritant effects. Calcium phosphate nanoparticles have been shown to be a lesser irritant than the macroparticles. In the present study calcium phosphate nanoparticles were prepared with bovine serum albumin using different stirring times and each analysed for entrapment efficiency. The void calcium phosphate nanoparticles were injected intramuscularly into rats for testing the site-specific inflammation. The muscle samples were collected on the 14th day of injection. The smallest particle size of about 40 μm of calcium phosphate nanoparticle–BSA complex was obtained by stirring for 1 h. The void calcium phosphate nanoparticles did not elicit any site-specific reaction in rats, as revealed by in histopathological examination. Hence calcium phosphate nanoparticles can be efficiently used as an adjuvant for non-live vaccines. However, further analysis of effects of calcium phosphate nanoparticles on the vital organs such as brain, liver, kidney is warranted.