In order to develop catechin patches for skin regeneration at wound sites, patches with varying concentrations of catechin and chitosan were manufactured. An optimal composition ratio was determined by adjusting the drug release rate and amount, to maximize efficiency. The catechin used in this study was extracted from green tea leaves using a solvent/ultrasonication method, and its characteristics were confirmed through Fourier transform-infrared spectroscopy (FT-IR) and high-performance liquid chromatography (HPLC) analyses. Patches were prepared with different concentrations of catechin and chitosan, and various properties were analyzed using techniques such as FT-IR, water contact angle analysis, and UV-Vis spectroscopy. It was observed that as the chitosan concentration increased, the release of catechin slowed down or almost ceased. A patch manufactured with 1.5 mg/cm2 of catechin at a 1 % chitosan concentration exhibited a high initial release rate over 24 h and demonstrated cellular biocompatibility. Consequently, these patches, with tailored release characteristics based on the concentrations of chitosan and catechin, hold promise for use as drug delivery systems in wound healing applications.

1. Introduction
2. Experimental Procedure
    2.1. Materials
    2.2. Catechin extraction
    2.3. HPLC analysis of extracted catechin
    2.4. Patch fabrication
    2.5. Release of catechin
    2.6. Measurement of contact angle
    2.7. Cell responses
3. Results and Discussion
    3.1. Confirmation of extracted catechins
    3.2. Fabrication of chitosan patches
    3.3. Measurement of contact angle
    3.4. Behavior of catechin release
    3.5. Cell responses
4. Conclusions
Acknowledgement

• Seunghwan Choy(Senior Researcher, Digital Health Research Division, Korea Institute of Oriental Medicine (KIOM)) Corresponding Author