Topical delivery of aceclofenac from lecithin organogels: preformulation study.

The purpose of this research is to evaluate the suitability of lecithin organogels containing aceclofenac for topical application. The present article focuses on the preformulation part of the whole research work. Thin layer chromatography was carried out to determine lecithin's purity. The excipients for formulating lecithin organogel were screened. Lecithin organogels are thermo reversible in nature and hence gelation temperature study was carried out to determine the temperature where Sol-Gel and Gel-Sol transformation takes place. Partition coefficient of the drug was estimated. Drug solubility in plain oil and organogel containing reverse micelles was estimated. Effect of water added on the properties of lecithin organogels such as X-ray diffraction pattern, conductivity and viscosity were determined. Microscopy of the gel sample has been carried out at different magnifications. The pseudo ternary phase diagram has been constructed to determine the organogel existence region. The permeation study of aceclofenac from different concentrations of lecithin organogels [200 mM, 300 mM and 400 mM] has been determined using cellulose acetate membrane (0.45 micro) and excised rat skin. Lecithin organogel in ethyl oleate has desired stability and consistency. A single spot on the TLC plate confirms the purity of soy lecithin to be used in organogel formation. Aceclofenac solubility was found to be more in lecithin/oil reverse micellar system as compared to its solubility in oil. The X-ray diffraction pattern confirms the incorporation of water in micellar gel network. The physical properties of organogels are affected by water incorporated and concentration of gelator. The permeation of aceclofenac through artificial membrane and excised rat skin demonstrated the same trend and were in the following order 200 mM>300 mM>400 mM. The results showed that organogel exhibits useful pharmaceutical properties.