Ocular fungal infections can pose severe health conditions that may develop into vision impairment and
blindness. Sertaconazole (STZ) is a widely used antifungal; however, its low aqueous solubility restricts its topical application for managing ocular keratitis. This investigation aimed to develop polymeric nanoparticles as delivery carriers to improve the ophthalmic availability of STZ for treating fungal keratitis. The impact of STZ solid dispersion incorporation within polymeric nanoparticles for in vitro drug release enhancement was also evaluated.
STZ-laden PLGA NPs were formulated via nanoprecipitation technology, using a 24-full factorial layout to
optimize the formulation. The formed nanoparticles were assessed for encapsulation efficiency percentage, hydrodynamic size, surface charge, and polydispersity index. The selected formula exhibited a particle size of 305.9 ± 4.36 nm, an entrapment efficiency (EE%) of 98.8 ± 0.008%, a surface charge of 22.57 ± 0.23 mV, and a low polydispersity index, indicating a uniform size distribution. Incorporating STZ in a solid dispersion form with PEG 2000 at a 1:3 w/w drug-to-carrier ratio increased the hydrodynamic size of the PLGA NPs. However, no significant variation in the entrapment efficiency percentage was recorded. The developed STZ-solid dispersionloaded PLGA NPs have round-shaped structures. DSC and FTIR spectroscopy data indicated drug amorphization with successful loading within the PLGA matrix. Introducing the drug as a solid dispersion within PLGA NPs resulted in enhancing the rate of drug dissolution at initial time intervals, followed by a controlled drug release over 24 h. STZ-PEG2000-laden PLGA NPs enhanced permeability through rabbits’ corneas (Papp), 2.5-fold higher versus STZ-loaded PLGA NPs. The antimycotic activity of the developed formulation was tested against Candida albicans, and a 4-fold reduction in the MIC value was detected upon applying the nanoparticles’ formulation embedding STZ solid dispersion versus that containing the free drug. In conclusion, the formulation of solid dispersions of STZ loaded in PLGA nanoparticles may serve as a starting point for an efficient approach to the ocular delivery of hydrophobic medications and a viable setup for the upcoming research in animal models of fungal keratitis.