The study of human skin irritation of a novel herbal skin care product and ingredients by human single closed patch testing

Abstract

Background: The Government Pharmaceutical Organization of Thailand (GPO) has developed many products using liposome nanotechnology and Thai herbal extracts. Objective: Evaluate the irritation potential of GPO products on human skin using the single application closed patch test under occlusion. The authors also studied the moisturizing efficacy of a commercial curmin extract cream (GPO curmin cream). Material and Method: Thirty-six female volunteers were tested with 12 test materials developed by GPO including liposome, curmin extract: tetrahydrocurcuminoids (THC), and commercial curmin cream. Two and a half percent sodium dodecyl sulfate (SDS) was used as positive control. Standard Finn chambers on Scanpor tape with webril cotton were used as occlusive patch test devices. Cutaneous irritation responses were graded after patch removal and the incidence of irritation compared to the positive control was used for evaluation. Corneometer was used to measure skin hydration before and after application of curmin cream. Results: All volunteers completed the present study. The skin irritation effects from the test materials were significantly lower (p-value < 0.001, McNemar statistic test) than the positive control. Measurement of skin hydration after twice daily application of GPO curmin cream was significantly higher (p-value < 0.001, paired t-test) than the control skin. Conclusion: The test materials and finished products developed by the GPO are not likely to induce skin irritation under normal conditions of use. Furthermore, twice-daily application of the commercial GPO curmin cream can significantly increase skin hydration.