Preparation and optimization formulation of zedoary turmeric oil nanoemulsion based thermo-sensitive gel for improved application in ophthalmology

Abstract The purpose of the current study was to design and develop a dosage form of zedoary turmeric oil nanoemulsion based thermo-sensitive gel (ZTO-NETG), improved the solubility and stability of zedoary turmeric oil and provided an ocular delivery strategy for the treatment of Herpes Simplex Keratitis. ZTO-NETG was prepared by phase inversion method and pseudo-ternary phase diagram, response surface experiment design was employed for the optimization of formulation. Physicochemical properties, in vitro drug release, stability studies stability and prediction of the validity by the classical thermostatic method of the optimized ZTO-NETG formulation were investigated. Moreover, modified Draize tests was applied to evaluate the ZTO-NETG formulation ocular irritation. The optimized ZTO-NETG showed the size of 98.52 nm, polydispersity index of 0.180, Zeta potential of - 4.12 mV and the drug content of Germacrone 97.8% and Furanodiene 102.3%. Viscosity and rheology demonstrated that ZTO-NETG had thinning effect, invitro release study showed that the release kinetics of the optimized gel conformed to zero-order drug release. Ocular irritation tests indicated that the eyes could tolerate the optimized ZTO-NETG. The result of the stability test was proved that the optimized gel had good physical stability, and the validity period of ZTO-NETG was 4 months. In conclusion, this thermo-sensitive gel formulation strategy could be used as a viable option for ocular administration of zedoary turmeric oil to treat Herpes Simplex Keratitis.