This study was designed to evaluate suitability of chitosan polymer as a vehicle for topical delivery system. Quercetin (QUT) is a natural flavonoid, was incorporated into the gel vehicles in a concentration of 0.5% w/v. Gels were prepared with three different concentrations and different molecular weights of chitosan. Viscosity, drug release from prepared gels, permeation of drug through skin rat and anti-inflammatory activity of the drug using carrageenan induced rat paw edema method were studied. In-vitro release characteristics of the drug from different gels were carried out using dialysis membrane in phosphate buffer, pH 5.5. The release data were treated with various kinetic principles to assess the relevant parameters. The general rank order of QUT release was F1 > F4 > F2 > F3 > F5. The results also showed that, the release of drug from the prepared gels obeyed the diffusion model (Higuchi’s equation). The results revealed an inverse correlation between the drug release percent and the polymer concentration used. The permeation of drug through skin rat was carried out. The flux of drug is independent on the viscosity of the formulae. The results also showed a significant anti-inflammatory activity on rat paw edema.

Curcumin (CUR) is one of the most commonly used herbal product; it shows effective antiinflammatory
and anti-oxidant effects. However, poor aqueous solubility and low permeability
are the major challenges in therapeutic application of curcumin. One class of vesicular
nanocarriers called “Niosome and ethosome” which have proved to possess distinct advantages
were used to encapsulate curcumin and evaluated for their morphology, particle size, zeta
potential, entrapment efficiency (EE%) and drug release. They were incorporated into hydroxy
propyl methyl cellulose (HPMC15000) gel then, evaluated on the rat skin via inhibition of
carrageenan induced rat paw edema. The results showed that the particle size of curcumin
loaded niosomes and ethosomes were ranged (317.5±1.91 to 558.3±8.587 nm) and (182.1±5.3 to
354.5±30.03 nm), respectively. Skin permeation studies demonstrated that CUR permeability
coefficient through rat kin for gel formulations of loaded vesicles was ~ four times higher as
compared to free CUR. The in-vivo anti-inflammatory studies proved that gel formulations of
CUR vesicles possessed higher significant inhibition of carrageenan induced rat paw edema
when compared to pure curcumin. Accordingly, the results revealed that, curcumin loaded
nanovesicels held great potential approaches as anti-inflammatory in topical application.