High performance liquid chromatography

URM (Figure 1B, purity >98%) was purchased from Absin Bioscience Inc. (Shanghai, China). UNO (Figure 1C, purity >98%) and SCN (Figure 1D, purity >98%) were purchased from Chengdu Biopurify Phytochemicals Ltd. (Chengdu, China). High-performance liquid chromatography (HPLC) grade acetonitrile, HPLC grade methanol and liquid chromatography coupled with mass spectrometry (LC–MS) grade ammonium acetate were purchased from Sigma-Aldrich (St. Louis, MO, USA). LC–MS grade formic acid (purity >98%) was obtained from J&K Technology Co., Limited (Beijing, China). Deionized water was prepared by a Milli-Q ultra-pure water purification system (Millipore, Molsheim, France).

Phosphatidylcholine (PC) from soybean source was a gift from LIPOID LLC (Newark, NJ, USA). Kolliphor^® P407 (P407) was generously donated by BASF Corporation (Tarrytown, NY, USA). Cholesterol (Chol) was purchased from Alfa Aesar (Haverhill, MA, USA). Cetylpyridinium chloride (CPC), quercetin (QCT), ethanol, and isopropanol were purchased from Sigma-Aldrich (St. Louis, MO, USA). Meloxicam (MX) was supplied from Acros Organics (Morris Plains, NJ, USA). Dihydroquercetin (DHQ) was purchased from Cayman Chemical Company (Ann Arbor, MI, USA). High-performance liquid chromatography (HPLC) grade water and acetonitrile were purchased from Sigma-Aldrich and Midland Scientific (Omaha, NE, USA), respectively. 1.1-Dioctadecyl-3,3,3,3-tetramethylindocarbocyanine perchlorate (Dil) was procured from AAT Bioquest (Sunnyvale, CA, USA). Dermatomed human cadaver skin was obtained from New York Firefighter Skin Bank (NY, USA). All other chemicals used were of reagent grade and purchased from VWR International (Radnor, PA, USA).