Development and Evaluation of a Novel Herbal Emulgel for Potential Anti-Inflammatory and Antioxidant Activities <em>in Vitro</em>

Abstract

Emulgel is a novel topical drug delivery system which can overcome the major limitation of gel; limited delivery of hydrophobic drugs. Leea indica (Burm.f.) Merr. (Burulla) is a medicinal plant used in Sri Lankan Ayurvedic medicine for many therapeutic purposes. The present study was aimed to develop a novel herbal emulgel using Leea indica leaf extract and evaluate in vitro anti-inflammatory and antioxidant activities. Different formulations (Fg1-Fg5) were prepared by incorporating freeze dried powder of 70% aqueous acetone leaf extract. All formulations (Fg1-Fg5) were tested for their physicochemical stability parameters such as pH, appearance, odor, homogeneity, spread ability, phase separation and washability for 60 days and they were subjected for in vitro anti-inflammatory activity by Human Red Blood Cell membrane stabilization assay and in vitro antioxidant activity by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay respectively. Two commercially available gels were used as the positive control. Among the formulated herbal emulgels, Fg5 showed the significantly high values of in vitro anti-inflammatory and antioxidant activities compared to the tested positive controls. At the concentration of 12.5 mg/mL, Fg5 showed percentage inhibition of 93.73 ± 0.90% of heat induced hemolysis of erythrocytes and in vitro antioxidant activity of Fg5 was 3.39 ± 0.01 mmol Trolox per 100 g of emulgel. All formulated emulgels were found to be semisolid, homogenous, and washable with water, having no phase separation and pH of the formulations were reported in the range of 6 to 7. There was no remarkable variation of stability parameters tested during 60 days. It is concluded that the formulated herbal emulgels have promising anti-inflammatory and antioxidant activities and formulation Fg5 can be recommended for further investigations using in vivo models.