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Abstract #82571 Published in IGR 20-4
Δ-Tetrahydrocannabinol Derivative-Loaded Nanoformulation Lowers Intraocular Pressure in Normotensive Rabbits
Taskar PS; Patil A; Lakhani P; Ashour E; Gul W; Elsohly MA; Murphy B; Majumdar STranslational vision science & technology 2019; 8: 15
PURPOSE: Δ-Tetrahydrocannabinol-valine-hemisuccinate, a hydrophilic prodrug of Δ-tetrahydrocannabinol, synthesized with the aim of improving the ocular bioavailability of the parent molecule, was investigated in a lipid-based nanoparticle dosage form for ocular delivery. METHODS: Solid lipid nanoparticles (SLNs) of Δ-tetrahydrocannabinol-valine-hemisuccinate and Δ-tetrahydrocannabinol, along with a nanoemulsion of Δ-tetrahydrocannabinol-valine-hemisuccinate, were tested for glaucoma management in a normotensive rabbit model by using a multiple-dosing protocol. Marketed formulations of timolol maleate and pilocarpine HCl were also tested for their pharmacodynamic profile, post-single dose administration. RESULTS: A peak intraocular pressure (IOP) drop of 30% from baseline was observed in rabbits treated with SLNs loaded with Δ-tetrahydrocannabinol-valine-hemisuccinate at 90 minutes. Treated eyes of rabbits receiving Δ-tetrahydrocannabinol-valine-hemisuccinate SLNs had significantly lower IOP than untreated eyes until 360 minutes, whereas the group receiving the emulsion formulation showed a drop in IOP until 90 minutes only. In comparison to marketed pilocarpine and timolol maleate ophthalmic solutions, Δ-tetrahydrocannabinol-valine-hemisuccinate SLNs produced a greater effect on IOP in terms of both intensity and duration. In terms of tissue concentrations, significantly higher concentrations of Δ-tetrahydrocannabinol-valine-hemisuccinate were observed in iris-ciliary bodies and retina-choroid with SLNs. CONCLUSION: Δ-Tetrahydrocannabinol-valine-hemisuccinate formulated in a lipid-based nanoparticulate carrier shows promise in glaucoma pharmacotherapy. TRANSLATIONAL RELEVANCE: Glaucoma therapies usually focus on decreased aqueous humor production and increased outflow. However, such therapy is not curative, and there lies a need in preclinical research to focus efforts on agents that not only affect the aqueous humor dynamics but also provide neuroprotection. Historically, there have been bench-scale studies looking at retinal ganglion cell death post-axonal injury. However, for a smooth translation of this in vitro activity to the clinic, animal models examining IOP reduction, i.e., connecting the neuroprotective activity to a measurable outcome in glaucoma management (IOP), need to be investigated. This study investigated the IOP reduction efficacy of cannabinoids for glaucoma pharmacotherapy in a normotensive rabbit model, bringing forth a new class of agents with the potential of IOP reduction and improved permeation to the back of the eye, possibly providing neuroprotective benefits in glaucoma management.
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Classification:
3.8 Pharmacology (Part of: 3 Laboratory methods)
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
5.3 Other (Part of: 5 Experimental glaucoma; animal models)