B. Usha Sri

The objective of current research is to formulate and evaluate Naproxen emulgel for tropical drug delivery. Naproxen Emulgels (F1-F10) were formulated by using Carbopol 940 with 0.5% w/w and HPMC K100 with 2.5% w/w. Arachis oil containing Span 20 acts as oil phase and water containing Tween 20 constitutes aqueous phase. All the formulations tested for physical appearance, homogeneity and consistency. All the emulgels were found to be opaque, homogenous, with good consistency and no phase separation. The drug content of all formulations recorded within 98.57±0.25 to 99.60±0.22% indicating content uniformity. In vitro release studies indicate higher release rate for F4 and F9 in 5 hrs of 99.68±0.54% and 92.65±0.61% respectively. The percentage ex-vivo drug release of F4 at 6 hrs was 98.98±0.41% which is higher than market formulation (66.94±0.51 %).The release kinetics data indicate that the drug released by Fickian diffusion predominated with all formulations. Based on permeability (2.49 x 10-3cm2/h) and enhancement ratio (2.22) F4 is considered as optimized formulation. The formulation F4 shows higher enhancement ratio than that of F9 and marketed gel, hence considered optimized formulation. Drug excipient compatibility studies by FTIR and DSC indicate no significant interaction. No significant changes observed in physicochemical properties of optimized formulation (F4) on exposure to accelerated conditions of temperature and humidity. Hence the developed Naproxen emulgel formulation was found to be stable with no skin irritations, increased absorption and drug release.

Oral route is the easiest and most convenient route for drug administration.  The major problem in oral drug formulations is low and erratic bioavailability, which mainly results from poor aqueous solubility. This may lead to high inter and intra subject variability, lack of dose proportionality. It is estimated that 40% of active substances are poorly water soluble. The solubility of such drugs is increased by formulating self emulsifying drug delivery system (SEDDS). Self emulsifying drug delivery systems have gained exposure for their ability to increase solubility and bioavailability of poorly water soluble drugs. SEDDS are isotropic mixtures of oil, surfactants, solvents and co-solvents/surfactants, which emulsify to produce fine oil-in-water emulsions upon gentle agitation. SEDDS typically produce emulsions with a droplet size between 100–300 nm. Solid SEDDSs are being developed from liquid/semisolid SEDDS mainly by adsorption on solid carriers, spray drying, lyophilization, melt extrusion, and nanoparticle technology. This review focuses on newer approaches for development of SEDDS and Solid SEDDS.