Study On Stability Of β-Arbutin In Cosmetic And Dermal Sensitization Quantitative Risk Assessment

Objective:To study the condition which could convertβ—arbutin in cosmetic into Hydroquinone during using cosmetic,and assess the risk of this conversion.Methods:①Monitoring cosmetic adverse reaction in china from 2005 to 2007,and the general information of cases,site,month and weather of dermatitis induced by spot banishing cosmetics were investigated.Allergen screen was conducted in some dermatitis cases induced by spot banishing cosmetics.②Arbutin was dissolved in acidulous solution(pH5.2)and incubated for 72h, and then arbutin and HQ in solution were analysed by HPLC.③Arbutin was dissolved in acidulous solution(pH6.88,pH5.2or pH5.5 artificial sweat)and incubated withβ-glucosidase.Then arbutin and HQ in solution were analysed at 0,0.5,1.5,3,4,5,6 and 24h after incubation by HPLC.Arbutin aqueous solution incubated withβ—galactosidase for 24h and analyse the HQ.Microorganism taking from derma of health person and staphylococcus aureus respectively cultured for 12h,then incubated with arbutin repectively for different time.And then arbutin and HQ were analysed by HPLC.④The samples were subjected to the analysis for arbutin and HQ by HPLC fitted with a C18-column(250* 4.6m mm,25℃) and aqueous acetonitrile +triethanolamine(pH7.7) served as the mobile phase,their UV-spectra(k =280nm)。⑤Detect the pH of 240 spot banishing cosmetics.Detect the dermal pH of 26 health persons when sweating and no sweating.Detect theβ-glucosidase in dermal tissue of health person refer to Lojda method.⑥Percutaneous absorption of arbutin and HQ was studied using TK-6H diffusion cell with pig derma.⑦Irritation and sensitization potential of arbutin and HQ was tested by HET-CAM,EPISKIN mothod and h—CLAT.And risk of conversion from arbutin into HQ was assessed referring to The SCCP'S Notes of Guidance for the Testing of Cosmetic Ingredients and their Safety Evaluation and QRA.Results:①Arbutin could not be converted into Hydroquinone only in acidulous solution or byβ—galactosidase,but could be converted into HQ byβ-glucosidase.Acidulous solution and artificial sweat could promote the conversion of arbutin,and artificial sweat promoted it more powerful than Acidulous solution.48%and 87%arbutin was converted into HQ respectively at 6h and 24h under the promotion of sweat.90.7%arbutin could convert into HQ after incubated for 48h with microorganism taking from derma of health person.But staphylococcus aureus could not convert arbutin into HQ.②pH of 75.8%spot banishing cosmetics＜7.0.Dermal pH of 26 health persons＜7.0(4.985 at nasolabial sulcus,4.921 at forehead,5.079 at cheek) and the pH decreased significantly(p＜0.01) after sweating.β-glucosidase was found in epidermis and hypoderma.③Cosmetic adverse reaction monitoring found that many adverse reaction are related to spot banishing cosmetics,and 59%of these cosmetic contain arbutin.Many dermatitis induced by spot banishing cosmetics occured during JUN.to OCT.and more occurred in weather of high temperature and humidity.About 51.06%of these dermatitis patients related to spot banishing cosmetics were allergic to TBHQ.④Arbutin and HQ could transfer through derma and HQ is easier transdermal than HQ.Arbutin is benefit for transdermal in 5%of concentration and 5h of contact time.⑤HET-CAM,EPISKIN test and h—CLAT test show that arbutin has no irritation and sensitization,HQ in no cytotoxic concentration(13.33μg/mL,20 g/mL和30μg/mL) induced RFI(%)(CD86)＞150 and RFI(%)(CD54)＞200. Risk assessment showed that the risk of sensitization would be unacceptable if more than 0.015%arbutin was converted into Hydroquinone,Conclusion:①Arbutin in cosmetics could be converted into HQ by dermal microorganism andβ-glucosidase in skin during foreseeable usage,and the conversion ratio will be promoted when sweating.②Persons using cosmetics contain arbutin for long time may be induced anaphylactic reaction because the risk of sensitization would be unacceptable if more than 0.015%arbutin in cosmetics converted into HQ.We speculate that some dermatitis related to spot banishing cosmetics in china maybe induced by HQ converted from arbutin in cosmetics.③Suggest that revise the cosmetic hygiene standard to setup some limits for arbutin used in cosmetic.