JOURNAL OF COSMETIC SCIENCE 262 Skin-pH meter (Courage and Khazaka Electronic GmbH), respectively. After completing baseline measurements, color photographs of subjects were taken. After that, all subjects received the test or control patch (three pieces/1 week usage) for using at home and were asked to record in their diary any abnormal sensation and/or feeling from the application of the patches. Subjects were instructed to apply the received patches every two days (Monday, Wednesday, and Friday) by slightly pressing them on the hyperpigmented area at night after facial cleansing. The duration of application for each night was 30 min. Any facial product except products containing steroids, photosensitizing, and depigmenting agents were allowed to be used at the patch-applied area after 20 min of the patch ap- plication. At week 1, 3, 6, and 8 of study period, subjects arrived at the test room around 8.00 am and waited for 30 min before evaluation of their skin properties. The dermatolo- gist also assessed the irritation score on the applied area. Subjects were asked to return the package of used products while receiving the new one at each visit. In addition, the ap- plication time recorded in the personal diary was also examined. STATISTICAL ANALYSIS All data were expressed as the mean ± standard deviation (SD). Student’s t-test was used for comparison the skin parameters between two independent groups, and analysis of variance (ANOVA) was used for multiple comparisons. p 0.05 was considered statisti- cally signifi cant. RESULTS CONTENT OF ARTOCARPIN IN THE ARTOCARPIN-ENRICHED EXTRACT The extract was a dry yellow powder. The artocarpin content was 89.5 ± 6.5% w/w, ac- cording to an HPLC assay. CHARACTERISTICS OF THE FORMULATED CHITOSAN HYDROGEL PATCH INCORPORATING THE EXTRACT When the chitosan solution was blended with the microemulsion in the ratio of 1:1 by weight, it was observed that they were compatible. The formulated patches were yellow- ish, transparent, and glossy in appearance (Figure 1). The ultimate tensile strength of the patches was 5.07 ± 0.08 N/mm2, the percentage of elongation at the break point was 35.04 ± 0.14%, and the moisture content was 51.4 ± 0.9%. The surface morphology of the formulated patches was rough and porous as can be seen in the photomicrographs (Figure 2). RELEASE OF ARTOCARPIN FROM THE FORMULATED PATCH INCORPORATING THE EXTRACT Figure 3 illustrates the cumulative amount of artocarpin released from the formulated patch after 30 min (67%) and after 240 min (86%). The release pattern exhibited two

CHITOSAN PATCH INCORPORATING A. ALTILIS HEARTWOOD EXTRACT 263 distinct phases a the rapid rate in the 0–15 min period, with an average release rate of 0.73 μg/min/mm2, and a slow rate from 15 min to 240 min, with the average release rate of 0.02 μg/min/mm2. Figure 1. An appearance of the formulated chitosan hydrogel patch incorporating the extract. Figure 2. Top surface (left) and cross-section (right) photomicrographs of the formulated patch.