The Inclusion of Timolol and Lisinopril in Calcium Phosphate Particles Covered by Chitosan: Application in Ophthalmology

Resumo

Chitosan-covered calcium phosphate nanoparticles with the mean dynamic radii of 30 to 130 nm and ζ-potential of +22 ± 4 mV containing timolol and lisinopril are prepared and characterized. These particles are formed by the amorphous phase represented by amorphous calcium phosphate Ca_x(PO₄)_y · zH₂O and the crystalline phase represented by hydrated calcium hydrophoshate (brushite) CaHPO₄ · 2H₂O. The experiments in vivo demonstrated that the inclusion of timolol into calcium phosphate particles covered with chitosan substantially prolonged its effect on the intraocular pressure.