FORMULATION AND IN VITRO CHARACTERISATION OF SOYBEAN OIL-HPMCK4M BASED BIGEL MATRIX FOR TOPICAL DRUG DELIVERY

Objective: Hydrogels with scope for utilization in numerous fields possess limited applications due to problems in incorporating wide range of drugs and crossing the lipophilic barrier of the skin. Attempts to overcome these problems by developing organogel hold drawbacks. Challenges posed by drug lipophilicity or skin permeation can be solved by developing bigel formed via combination of lipophilic and hydrophilic gel phases in a definite proportion. The objective of the present study is to formulate and characterize matrix type bigel of soybean oil and HPMCK4M for topical drug delivery. Methods: Four batches of bigels were developed with two organogel formulations of soybean oil containing 20 and 22% w/v Span 60. Both organogels and bigels were examined for compatibility by FTIR spectroscopy, hemocompatibility and characterized for physical appearance, pH, rheological behavior and in vitro drug release pattern. Results: FTIR study confirmed compatibility between paracetamol and components of organogel or bigel. The oily feel of organogels disappeared with bigels which possessed a creamy and smooth texture. Pseudoplastic behaviour was confirmed by Ostwald-de wale power-law model in both organogels and bigels. Improved drug release was observed in bigel (BG1) formulation containing 3%w/v HPMCK4M and soybean oil based organogel with 20% w/v Span 60 as compared to the corresponding organogel (OG1). Organogels were foundto follow either zero-order kinetics (OG1) or Korsmeyer-Peppasmodel (OG2) while the formation of matrix was exhibited in bigels with drug diffusion predominantly of non-Fickian type. Conclusion: Therefore, bigels of soybean oil based organogel with HPMCK4M hydrogel formed gel matrix demonstrating improved drug release for topical application compared to organogel