Skin irritation test of Thai herbal face wash gel formulations using the New Zealand white rabbits

Abstract

Keywords: Herbal formulation; Skin irritation test; Thai herbal face wash gel

Objectives: This work aimed to study the acute skin irritation: the erythema and eschar formation, and oedema formation, of Thai herbal face wash gel using the New Zealand white rabbits.

Methods: The Thai herbal face wash gel incorporated the Curcuma longa L. : Areca catechu L. : Oryza sativa L. : Garcinia mangostana L. in ratio of 1:1:1:1, respectively. The Thai herbal extract was loaded in each microemulsion system or self-microemulsifying system. They were vortexed for 30 second to form the clear yellow solution and mixed in face wash gel formulation. Then, the 0.5 g Thai herbal face wash gel-based on microemulsion system or self-microemulsifying system was applied on the New Zealand white rabbits for acute skin irritation test. The 0.5 g distilled water was served as a control site. The erythema and eschar formation, and oedema formation were graded into five score on the each site of rabbit’s skin at 1, 24, 48, and 72 hours after removal of Thai herbal face wash gel.

Results: All treated New Zealand white rabbits exhibited the no oedema formation after apply with Thai herbal face wash gel. However, the rabbit number 5 and 7 showed the very slight erythema formation of the rabbit’s skin (scale 1) at 1 hour, and this was not presented at 24, 48, and 72 hours, while the other rabbit showed no erythema (scale 0) at any time of the investigations.

Conclusion: Both Thai herbal face wash gels – based on microemulsion system and self-microemulsifying system were safe to apply on the skin with very slight erythema formation at 1 hour and no oedema formation.