Design, fabrication, and characterization of graft co-polymer assisted ocular insert: a state of art in reducing post-operative pain.

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.

Effect of amphiphilic graft co-polymer-carrier on physical stability of bosentan nanocomposite: Assessment of solubility, dissolution and bioavailability.

Bosentan is a dual endothelin receptor antagonist used in the treatment of pulmonary arterial hypertension (PAH). But the solubility and bioavailability of this drug are poor, which has restricted the design and development of dosage forms for efficient and successful therapy. The present study was carried out to develop nanocomposites using an amphiphilic graft co-polymer (Soluplus®) as a carrier to enhance the solubility and bioavailability of bosentan. The graft co-polymer-based nanocomposite formulation was prepared using the single-emulsion technique. The nanocomposite was characterised in terms of particle size analysis, solubility, percentage entrapment efficiency, drug-loading capacity, surface morphology, drug content, in vitro dissolution, stability and bioavailability. FT-IR study revealed that there was no interaction between the drug and Soluplus®. DSC analysis of the nanocomposite formulation confirmed that the bosentan was completely encapsulated within a Soluplus®. XRD analysis showed that the drug was converted to an amorphous form irreversibly. SEM images showed that the particles were of size 96-129µm and had slightly smooth to rough textured surface. TEM analysis indicated that the diameters of the prepared bosentan nanocomposite after dispersion in distilled water were 13.69-96.78nm. Statistically significant increases in the solubility, dissolution and bioavailability of the drug were observed. It was confirmed that the use of a graft co-polymer carrier-based nanocomposite formulation is a good approach for efficient delivery of bosentan, the solubility and bioavailability being increased manifold.