Purpose: Targeted delivery of drugs at appropriate concentrations to ocular tissues is required to avoid wastage. Hence, advanced systems that maximize the release of poorly soluble drugs and deliver them at ocular sites must be designed.
Methods: In this study, Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol-graft copolymer) was selected as a solubilizer as well as film former for preparing ocular inserts and polyethylene glycol 400 (PEG-400) as a plasticizer. On the basis of an initial phase solubility study, the maximum concentration of Soluplus® possible was used for developing the inserts. An optimized formulation was obtained using a 32-factorial design. Two factors at three levels were used to design the ocular inserts. Soluplus® (X 1) and the plasticizer, PEG-400 (X 2), were set as the independent variables at various levels, and the Rel4h (drug release in 4 h, Y 1) and tensile strength (Y 2) were set as the dependent variables. A pre-formulation study was conducted to select suitable materials.
Results: Various physico-chemical parameters of the optimized formulation, including the tensile strength and folding endurance, were studied using FT-IR, DSC, XRD, and SEM. An in vitro dissolution study was conducted to determine the amount of drug released. There was no redness, swelling, or watering of the rabbit eye.
Conclusion: It was concluded that the ocular inserts of the poorly soluble nepafenac developed using a graft-co-polymer enhanced the solubility and utilization of the drug for a prolonged period.
Keywords: Nepafenac; Ocular insert; Soluplus®; graft-co-polymer; ophthalmic drug delivery.