DoE based development and optimization of ion sensitive in situ nanoemulgel containing bimatoprost for sustained...

The primary treatment for glaucoma involves the chronic instillation (daily) of intraocular pressure (IOP)-lowering eye drops to manage disease progression and prevent vision loss. Bimatoprost is a prostaglandin analogue used in glaucoma and ocular hypertension.

The objective of the present study was to formulate and evaluate a novel in situ nanoemulgel (NEG) of bimatoprost for ocular drug delivery (ODD).

Bimatoprost (Drug), Hyaluronic acid (HA), Algal oil (oil phase), liquid soya lecithin (Emulsifier 1), and tween 40 (emulsifier II), and water (Aqueous phase) were components for the formulation, and the nanoemulsion was prepared by high-pressure homogenization. The optimization of formulation was done with Quality by Design (QbD), and the optimized formulation was further evaluated for Zeta size, Zeta potential, PDI, and Surface morphology. The final nanoemulsion formulation was transformed into a gel system using Gellan Gum (GG) as the gelling agent. After incorporation in the gelling system, the developed nanoemulgel (NEG) was further evaluated for clarity, pH, sol-gel transition, rheology, drug content, sterility, isotonicity, and in vitro drug release. Pharmacodynamic studies have been performed for the evaluation of IOP, Dry eye test, and conjunctival hyperemia measurement.

Optimized nano emulsion had 7.5 % oil, 22.5 % Liquid soya Lecithin & Tween 40 [S_mix(1:1)] and 70 % water with particle size, Zeta potential and Poly dispersed index (PDI) range as 38.87 ± 0.91, 34.3 ± 0.34 and 0.282 ± 0.04 respectively. The developed formulation (NEG) showed evidence of sol-gel transition or in situ gelation after combining with artificial tear fluid. The drug content in developed NEG was found to be 99.76 ± 0.65 %. In-vitro drug release results of optimized bimatoprost-loaded NEG offered sustained delivery of the drug with an anisotropic diffusion. The developed formulation was found to be stable, isotonic, and sterile. Pharmacodynamic evaluation revealed a significant decrease in IOP with the developed formulation (NEG). Other than this, adverse drug reactions (ADR) associated with anti-glaucoma medication, i.e., dry eye and conjunctival hyperemia, were addressed by developing NEG with omega-3 fatty acid and HA.

This novel formulation offers a competitive option to traditional eye drops because of its prolonged precorneal residence duration and sustained medication release. Pharmacodynamic evaluations demonstrated that the developed NEG formulation enriched with omega-3 fatty acids and hyaluronic acid (HA) provided superior glaucoma management while simultaneously mitigating the adverse effects commonly associated with conventional anti-glaucoma therapies.