The current study aimed to determine the effect of inclusion of a mucoadhesive agent on the intensity and duration of intraocular pressure (IOP) lowering activity of Δ9-tetrahydrocannabinol-valine-hemisuccinate (THC-VHS) loaded in a nanoemulsion (THC-VHS-NE) formulation. THC-VHS-NE formulation with Carbopol®940NF added as a mucoadhesive agent (THC-VHS-NEC) was prepared using hot-homogenization followed by probe sonication and characterized. A comparative evaluation of the IOP lowering activity of THC-VHS-NEC, THC-VHS-NE, THC-NEC, and commercial latanoprost ophthalmic solution, was undertaken in normotensive New Zealand white rabbits. The effect of pH, surfactant concentration, and autoclave process on the IOP lowering activity of THC-VHS-NEC was also studied. The formulation demonstrated desired viscosity, physicochemical properties, and autoclave process stability. The THC-VHS-NEC formulation showed a significant (p < 0.05) improvement in the duration of IOP lowering activity, compared to THC-NEC and THC-VHS-NE. Moreover, in this model, THC-VHS-NEC was more effective than commercially available latanoprost ophthalmic formulation, in terms of both duration and intensity of IOP lowering. A change in formulation pH, surfactant concentration, or sterilization process did not impact the IOP lowering activity of THC-VHS-NEC. Overall, inclusion of a mucoadhesive agent in THC-VHS-NE formulation, significantly increased the duration of activity, and could lead to a once- or twice- a day dosing regimen.
Keywords: Autoclave; IOP; Mucoadhesive agent; Nanoemulsion; Rabbits; Δ(9)-tetrahydrocannabinol-valine-hemisuccinate.
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