Evaluation of diclofenac niosomal gel formulated with Grewia gum for topical delivery

Abstract

The purpose of this study was to formulate niosomal gel for topical delivery of diclofenac using Grewia gum as gelling agent. Niosomes containing 1g of diclofenac were formed using the thin film hydration (TFH) method. Niosomal gels were then formulated using a semi-synthetic polymer, hydroxypropylmethylcellulose (HPMC) and a natural polymer, Grewia gum as gelling agents. The formulated gels were evaluated for spreadability, viscosity, extrudability, homogeneity, clarity and pH. Results show that gels having pH and viscosity ranges of 6.8-7.3 and 265-490 Poise respectively were formed. The gels were homogenous, clear and showed good spreadability and extrudability except for batches F7 and F8. The gels formulated using the test gum, Grewia gum compared favourably with those of the standard polymer, HPMC as well as with the marketed gel. Formulation F5 containing 2% w/w Grewia gum, the optimized batch, showed viscosity of 265 poise, pH of 6.9, spreadability and extrudability values of 5.55 cm and 5.00 g/s respectively. In conclusion, Grewia gum at a concentration of 2% w/w could be used in the formulation niosomal gel for the delivery of diclofenac, which would help to circumvent the potential gastric irritation of diclofenac when used orally. Keywords: Niosomes; Grewia gum; Diclofenac; Lipid hydration; Topical delivery