Objective  To investigate the preparation of curcumin nanoparticles supported by chitosan deoxycholic acid, and to observe the effect of curcumin nanoparticles on human retinal pigment epithelial cell cycle.

  Methods  Curcumin nanoparticles were synthesized by using chitosan grafted with deoxycholate group as carrier and curcumin as supported drug. The load factor and drug-loading rate of the nanoparticles were determined. The shape and structure of the nanoparticles were observed and the amount of their release in vitro was determined. The optical density (OD) values of human retinal pigment epithelial cells treated with chitosan deoxycholic acid nanoparticles at 24 and 48 h were measured, and the cell morphology was observed. The changes of curcumin nanoparticles and curcumin on human retinal pigment epithelial cell cycle were determined.

  Results  Chitosan deoxycholic acid nanoparticles mixed with curcumin and chitosan deoxycholic acid were light yellow. Chitosan deoxycholic acid nanoparticles of unloaded drug were spherical or spherical with an average particle size of 30 to 50 nm, and chitosan deoxycholic acid nanoparticles loaded with curcumin had an average particle size of 70 to 100 nm; the drug-loading rate was 27.5% and the load factor was 55.0%. After 96 h, the drug release from the nanoparticles reached equilibrium, and the drug accumulate release rate reached 31.6%. OD values of human retinal pigment epithelial cells treated with different concentrations of chitosan deoxycholic acid nanoparticles for 24 and 48 h were not significantly different from those of the control group (P>0.05). After 24 h treatment with curcumin nanoparticles and curcumin, the percentage of cells in S phase decreased and that in G₀ to G₁ phases increased.

  Conclusion  Curcumin nanoparticles coated with chitosan deoxycholic acid can continuously release curcumin with good slow-release function. Curcumin nanoparticles can block the human retinal pigment epithelial cell cycle from S phase.