Morphologic design of nanogold carriers for a carbonic anhydrase inhibitor: Effect on ocular retention and intraocular pressure.

Morphologic design of nanomaterials for a diversity of biomedical applications is of increasing interest. The aim of the current study is to construct therapeutic gold nanoparticles of different morphologies and investigate their effect on ocular retention and intraocular pressure in a glaucoma rabbit model. Poly(lactic-co-glycolic acid) (PLGA)-coated nanorods and nanospheres have been synthesized and loaded with carbonic anhydrase inhibitor (CAI), and characterized in vitro for their size, zeta potential and encapsulation efficiency. Nanosized PLGA-coated gold nanoparticles of both morphologies demonstrated high entrapment efficiency (˃ 98%) for the synthesized CAI and the encapsulation of the drug into the developed nanoparticles was confirmed via Fourier transform-infrared spectroscopy. In vivo studies revealed a significant reduction in intraocular pressure upon instillation of drug-loaded nanogold formulations compared to the marketed eye drops. Spherical nanogolds exhibited a superior efficacy compared to the rod-shaped counterparts, probably due to the enhanced ocular retention of spherical nanogolds within collagen fibers of the stroma, as illustrated by transmission electron microscopy imaging. Normal histological appearance was observed for the cornea and retina of the eyes treated with spherical drug-loaded nanogolds. Hence, incorporation of a molecularly-designed CAI into nanogold of tailored morphology may provide a promising strategy for management of glaucoma.