JOURNAL OF COSMETIC SCIENCE 268 irritants (23). When the test patches were applied on subjects’ faces for 8 weeks (three times/week, 30 min for each time), erythema, scaling, and oedema on applied area were not observed, and the skin pH at the applied area was maintained in the normal range (5.5–6.5). These results demonstrate the safe and benefi cial use of the tested patches for use in cosmetics. The outermost layer of the skin is the stratum corneum which plays a role as a barrier layer relying on its lipid and keratin composition and organization. The skin permeation of compounds such as artocarpin, which has a large size (MW 400 dalton) and lipophilic nature (log partition coeffi cient, log P 4) is generally poor (24,25). Reversible alteration of the organization of keratinized protein and/or fl uidization of the lipids by using per- meation enhancers is widely implemented to improve the skin permeation of poor perme- ation compounds. In the present study, the extract enriched with the bioactive compound, artocarpin, was formulated into the hydrogel patch to improve skin permeability of arto- carpin. Water molecules accumulated in the stratum corneum during patch application which contributed to skin moisturization and acted as a permeation enhancer by chang- ing the structure of the keratinized protein in the stratum corneum (26). The microemul- sion nonionic surfactant (Tween® 80) present in the formulated patch also facilitated the permeability of bioactive components by reversely changing the conformation and/or fl uidization of the lipid bilayer (26). We found that the formulated patch containing the extract (0.07 mg of extract/cm2 of patch) signifi cantly improved the hyperpigmented area after 3 weeks of application. This implies that the amount and rate of release of artocarpin from the formulated patch achieved an effective topical delivery, and in addition, a sig- nifi cant increase in the skin moisture content was found after patch application. In conclusion, the artocarpin-enriched A. altilis heartwood extract was formulated into a hydrogel patch by using a microemulaion technique to solubilize the lipophilic extract and by using polymeric chitosan to control the delivery of the artocarpin. The formulated patch was effective in skin depigmentation and was mild on the skin causing no skin red- ness or irritation. However, the small number of subjects in this study did not in- clude the variety of skin types which may be found in studies with a larger more diverse sample. Future studies with a larger number of subjects and a longer duration should be performed to confi rm the benefi cial effects of the formulated patch for improving hyperpigmentation. ACKNOWLEDGEMENTS Financial supports from the Commission on Higher Education, Ministry of Education, Thailand, and International Laboratories Corp. Ltd. We also thank the Center of Excel- lence for Innovation in Chemistry (PERCH-CIC), the S&T Postgraduate Education and Research Development Offi ce (PERDO), the Commission on Higher Education for facil- ity support. Many thanks to Mr. Roy Morien of the Naresuan University Language Cen- tre for his editing assistance and advice on the English expression in this document. REFERENCES (1) M . S. Sikarwar, B. J. Hui, K. Subramaniam, B. D. Valeisamy, L. K. Yean, and K. Balaji, A. review on Artocarpus altilis (Parkinson) Fosberg (breadfruit), J. App. Pharm. Sci., 4, 91–97 (2014).

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