Topical delivery of acetazolamide by encapsulating in mucoadhesive nanoparticles

The intent of this study was to provide topical delivery of acetazolamide by preparing chitosan-STPP (sodium tripolyphosphate) nanoparticles of acetazolamide and evaluate the particle size, zeta potential, drug entrapment, particle morphology; in vitro drug release and in vivo efficacy. The particles showed sustained in vitro drug release which followed the Higuchi kinetic model. The results indicate that the nanoparticles released the drug by a combination of dissolution and diffusion. The optimised formulation was having particle size 188.46 ± 8.53 nm and zeta potential + 36.86 ± 0.70 mV. The particles were spherical with a polydispersity index of 0.22 ± 0.00. Powder X-ray diffraction and differential scanning calorimetry indicated diminished crystallinity of drug in the nanoparticle formulation. In the in vitro permeation study, the nanoparticle formulation showed elevated permeation as compared to that of drug solution with negative signs of corneal damage. In vitro mucoadhesion studies showed 90.34 ± 1.12% mucoadhesion. The in vivo studies involving ocular hypotensive activity in rabbits revealed significantly higher hypotensive activity (P < 0.05) as compared with plain drug solution with no signs of ocular irritation. The stability studies revealed that formulation was quite stable.