Formulation of Niosomes containing Phyllanthus Emblica extract with whitening and free radical scavenging activites

Abstract

The purposes of this study were to investigate anti-free radical and whitening activities of Phyllanthus emblica extract, to formulate and characterize niosomes containing emblica extract prepared by reverse phase evaporation method. Effect of surfactant type and surfactant : cholesterol ratio on the preparation and physicochemical properties of niosomes was studied. The emblica extract was prepared as lyophilized powder. The DPPH scavenging activity of emblica extract, which contained the main constituent namely gallic acid, with the IC₅₀ of 1.38±0.01μg/ml , was higher than ascorbic acid, whereas the standard gallic acid had the greatest activity. Embica extract exhibited lower antityrosinase activity than kojic acid, but much higher than alpha arbutin, with IC₅₀ of 0.97±0.06 mg/ml. Consequently, niosomes loaded with 0.5% weight by volume emblica extract could be prepared by reverse phase evaporation technique. Niosomes could be achieved by nine formulations using Span 20, Span 40, Span 60 and Span 80 with varied surfactant: cholesterol ratios of 1:1, 6:4, 7:3 and with Solulan C-24 as stabilizer. Vesicular size of all formulations determined by photon correlation spectroscopy technique were between 215- 306 nanometers. The size obtained from Span 20 (HLB 8.6) with shortest alkyl chain (C12), was larger than from Span 40 (HLB 6.7, C16) and Span 60 (HLB 4.7, C18). The formulation comprised of Span 20: cholesterol : Solulan C-24 of 57:38:5 by mole, showed the highest entrapment efficiency of gallic acid as 49.29±4.60 %, mean size of 273±7.9 nanometers and polydispersity index of 0.333±0.061. Vesicular size showed a little larger mean sizes at both 4°C and 30°C at 12 weeks, except the formulation with Span 80 showed phase separation after storage. The percentage content of gallic acid in niosomes decreased due to the degradation of gallic acid in a less amount at 4°C than 30°C . The serum formulation with loaded emblica extract niosomes was prepared with 16 % weight by volume of poloxamer 407 as viscosity enhancer. The in vitro permeation using newborn abdominal porcine skin as skin model revealed that niosomes showed higher permeation than its corresponding serum formulation. The niosomes comprised of Span 20: cholesterol : Solulan C-24 of 57:38:5 by mole enhanced the skin permeation as shown by the highest permeability coefficient of 0.0025±0.0009 cm/h, and highest percentage gallic acid deposited in the skin as 2.97±0.59%.