J. Cosmet. Sci., 68, 257–269 ( July/August 2017) 257 Formulation of chitosan patch incorporating Artocarpus altilis heartwood extract for improving hyperpigmentation JUTATIP KWANKAEW, PREEYAWASS PHIMNUAN, SOMBAT WANAUPPATHAMKUL, and JARUPA VIYOCH Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, 65000 Thailand (J.K., P.P., J.V.), and International Laboratories Corp. Ltd., Sadhupradist Road, Chongnonsi, Yannawa, Bangkok, 10120 Thailand (S.W.) Accepted for publication June 24, 2017. Synopsis Artocarpus altilis heartwood extract contains the bioactive compound artocarpin which exhibits melanogenesis inhibitory activity. However, the extract has poor solubility which affects the skin permeability of the compound. A chitosan hydrogel patch incorporating A. altilis heartwood extract was formulated to enhance the delivery of an amount of artocarpin suffi cient for depigmenting the skin. The extract was prepared as an o/w microemulsion before blending with an aqueous solution of chitosan. The hydrogel patch was formulated by blending in a 1:1 ratio by weight of 4% w/w chitosan solution and 0.04% w/w extract microemulsion which provides optimal values of the mechanical properties of the patch. The release of artocarpin from the formulated patch (artocarpin content, 0.07 mg/cm2) exhibited two phases the rapid rate (0–15 min) averaged 0.73 μg/min/mm2, and the slow rate (15–240 min) averaged 0.02 μg/min/mm2. The formulated patches signifi cantly improved the hyperpigmented area of the subjects after 3 weeks of application. No adverse events were observed. The results indicate that the formulated chitosan hydrogel patch delivers an effective amount of incorporated artocarpin depigmenting action. INTRODUCTION Artocarpus altilis belongs to the Moraceae family. This evergreen tree, called Sa-Kae in Thai, is found throughout the tropical areas of Southeast Asia and has long been used in traditional folk medicines. Several studies have shown that A. altilis heartwood extract contains phenolic compounds with the ability to inhibit the activity of tyrosinase (1–3), a key enzyme for melanin synthesis. Recent studies have identifi ed artocarpin as a major compound in A. altilis heartwood extract (4–8). The artocarpin in the extract decreases melanin production of B16F1 melanocytes (4,5) and exhibits skin depigmenting effects on the ultraviolet B (UVB)-induced hyperpigmented dorsal skin of C57BL/6 mice (4). Address all correspondence to Jarupa Viyoch at jarupav@nu.ac.th, jarupaviyoch4@yahoo.com.

JOURNAL OF COSMETIC SCIENCE 258 This suggests the potential of the extract for application in the depigmentation process. However, the incorporation of this extract in cosmetic formulations such as an oil-in-water emulsion is limited because of its low solubility in an aqueous phase, thus affecting its permeability through skin and its effi cacy at the action site. Artocarpin has poor ability to permeate through skin because of its large molecular weight (MW 400) and lipophi- licity (log partition coeffi cient 4). To improve this limitation, we formulated the extract into a form that can promote skin penetration of the compound, leading to enhanced depigmenting effi cacy. The hydrogel patch is a dosage form that is designed particularly for the delivery of the active compounds into the skin for fast activation of the desired amount which results from hydration of the stratum corneum. The hydrogel patch that we developed required an aqueous polymer to act as a rate-controlling matrix. Chitosan, a natural aqueous poly- mer, attracted our interest because of its biodegradability and nontoxicity. Previous stud- ies had shown that a patch prepared from chitosan exhibits good bioadhesion to the skin because of its net positive charge properties (9,10). In the present study, to incorporate the extract into the chitosan hydrogel patch, the extract was initially formulated into an oil-in-water (o/w) microemulsion, which was then blended with an aqueous solution of chitosan polymer (9). The resulting solution was then cast into a mold to shape the hydrogel patch. We were then able to determine the release charac- teristics of the artocarpin, the major bioactive component of the formulated patch, and test and clinically observe any resulting skin irritation as well as the effi cacy on skin depig- mentation of the formulated patch, and to evaluate its potential for skin depigmentation. MATERIALS AND METHODS PREPARATION OF THE EXTRACT The heartwood of A. altilis was collected on July (raining season) from Phitsanulok Province, Thailand. The heartwood portion was chipped and dried at 50°C by using a hot-air oven. The dried chipped heartwood (1 kg) was then macerated at room temperature for 2 cycles (2 days/cycle) with suffi cient diethyl ether (analytical grade, Labscan Asia, Co., Ltd., Bangkok, Thailand), according to our previous studies (6,7). The extract from each cycle was pooled and fi ltered through a fi lter paper to remove unwanted residue and concen- trated to dryness using a rotary evaporator. The extract was further dried in a desiccator, and kept in a tight amber glass bottle at 4°C for further studies. QUANTIFICATION OF ARTOCARPIN IN THE EXTRACT The content of artocarpin in the extract was determined by using isocratic high performance liquid chromatography (HPLC). The HPLC instrument consisted of an SPD-20A UV detector and an LC-20AP pump (Shimadzu Co., Ltd., Kyoto, Japan). A Phenomenex Gemini C18 column with 5 μm and 250 × 4.60 mm diameter was applied as the stationary phase. The mobile phase consisted of a mixture of methanol (analytical grade, Labscan Asia, Co., Ltd.) : water (80:20). The fl ow rate of mobile phase was set at 1 ml/min, and the injection volume was 20 μl. The quantifi cation of artocarpin was based on the peak area