Thermosensitive hydrogel containing sertaconazole loaded nanostructured lipid carriers for potential treatment of fungal keratitis

This study was conducted to develop an in situ thermosensitive gel containing sertaconazole-loaded nanostructured lipid carriers (NLCs) for prolonged ocular drug delivery. To this end, sertaconazole-loaded NLCs (sertaconazole-NLCs) were prepared by emulsification solvent-diffusion method and the effects of different formulation variables were assessed using the fractional factorial design. Then, optimized sertaconazole-NLCs were incorporated into the pluronic F127 (PF127)/hydroxy propylmethylcellulose (HPMC) K4M hydrogel. The formulations were examined for pH, gelation temperature, rheological properties, in vitro permeation studies, and anti-fungal activity. The optimized sertaconazole-NLCs showed a mean particle size of 272.40 nm, encapsulation efficiency of 89.97%, zeta potential of 12.9 mV, and polydispersity index of 0.31. All the in situ formulations had acceptable pH, ranging from 5.89 to 6.28. The gelation temperature of the optimized formulation was 35.1 °C after dilution with simulated tear fluid (STF). Sertaconazole-NLCs showed a higher antifungal activity and permeation through the bovine cornea compared to the free drug and the in situ gel formulation. The cornea penetration of sertaconazole for the in situ gel of NLCs was also comparable to that for free drug. The obtained results indicated that the prepared nanocomposite system may have potential for treatment of fungal keratitis.