Objective:The main purpose of the study was to develop niosomal in situ gel of prednisolone sodium phosphate (PSP) with increased bioavailability (enhanced permeation) and sustained action (drug retention at the target site). Methods:Using different ratios of span 60 and cholesterol (chol), niosomes were prepared by thin film hydration method and optimized by evaluating different parameters like drug content, entrapment efficiency, particle size and in vitro drug diffusion study. The niosomal pellets were further incorporated in in situ gel, prepared by the cold method and further optimized by parameters like gelling parameters, mucoadhesive strength and in vitro, in vivo drug release study. Results:The optimized niosomal formulation containing span 60 and chol in equal proportion (1:1) showed better drug content (DC) i.e. 86.3±0.39% and entrapment efficiency (EE) i.e. 83.4±0.22 with vesicle size of 465±0.24 nm. The in vitro drug diffusion study indicated t90 value of 490 min thus proving sustained action of the formulation. The optimized in situ gel containing poloxamer 407 (P407) and poloxamer 188 (P188) in the ratio of 1:2.7 showed gelation temperature at 37 ⁰C (physiological temperature of the body) and t90 value of 10 h thus depicting sustained action. The increased area under curve (AUC) value by 1.75 folds proved increased bioavailability of the drug. Conclusion:Thus sustained drug delivery with increased bioavailability was designed for prednisolone sodium phosphate for the treatment of ocular inflammation. I In nt te er rn na at ti io on na al l J Jo ou ur rn na al l o of f A Ap pp pl li ie ed d P Ph ha ar rm ma ac ce eu ut ti ic cs s

Introduction:Our main purpose of present study was to find out the effect of different crosslinking agents along with its concentration during polymer synthesis and to find the most suitable polymer for ocular drug delivery with optimum bioadhesive strength and less irritation potential. It was expected that the synthesized polymer will remain adhered to the conjunctival mucin layer thus preventing loss of drug by precorneal factors. Materials and methods: Acrylic acid procured from Loba chemicals was polymerized with Divinyl glycol from Merck specialities Private limited, Divinylbenzene and 2, 5-dimethyl-1, 5-hexadiene from Alfa Aesar to form water insoluble swellable polymer. Different parameters like density, polymer hydration, Differential Scanning Calorimetry, Infra-Red spectroscopy, X ray diffraction and mucoadhesive strength were determined. Polymer hydration was studied with respect to time, pH and ionic strength. HET-CAM test and Draize skin irritation test was performed to evaluate the degree of irritation caused by these polymers. Results and Discussion: It was found that as more hydrophobic groups were introduced in the polymer structure, hydration potential was reduced. The effect of concentration of crosslinking agent on bioadhesive strength was significant. With increase in density of crosslinking agent, the bioadhesive strength decreased. Polymers were found to be non-irritant to slight irritant in nature.