Dual controlled release effect of montmorillonite loaded polymer nanoparticles for ophthalmic drug delivery

Abstract

Montmorillonite based polymeric nanoparticles was designed to effectively deliver adequate concentrations of drug to the ocular site after topical administration for treatment of glaucoma. In vitro and in vivo studies were carried out to evaluate their drug delivery performances. Betaxolol hydrochloride (BH) intercalated montmorillonite (Mt-BH) was successfully encapsulated into the Eudragit®PO (Mt-BH NPs) via an opportunely emulsification-solvent evaporation technique as indicated by Fourier transform infrared, differential scanning calorimentry, and the nitrogen sorption and desorption isotherms. The resulting nanoparticle system showed the mean particle diameters of 82 ± 8 nm and positive ζ potentials, with encapsulation efficiency of 77 ± 1% and drug-loading rate of 8 ± 2%. Interestingly, in vitro release profile of Mt-BH NPs exhibits an initial burst of surface-bound BH, followed by a slow release of BH due to polymer erosion, and a further drug release after the particle completely breakdown. About 80% were released after 10 h. The designed drug delivery system showed little irritation and well tolerance of nanoparticles in a chorioallantoic membrane assay. The new Eudragit®PO polymer nanoparticles system reported here is expected to be useful in ophthalmic application.