Ultra low binding microcentrifuge tubes

Oxazepam, R,S-Oxazepam glucuronide, ketoconazole, β-glucuronidase, and bovine serum albumin (BSA) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Cannabinoids and their metabolites (THC, 11-OH-THC, THC-COOH, and CBD) were purchased from Cayman Chemicals (Ann Arbor, MI, USA) or Sigma-Aldrich after obtaining the appropriate Drug Enforcement Administration (DEA) licenses (state and federal). UDP-glucuronic acid (UDPGA) was purchased from Cayman Chemicals (Ann Arbor, MI, USA). Ultra-low binding microcentrifuge tubes, alamethicin, and magnesium chloride (MgCl₂) were purchased from VWR (Radnor, PA, USA). Sekisui Xenotech, LLC (Lenexa, KS, USA) supplied pooled human liver microsomes (HLM; n = 50 subjects, mixed gender) and human kidney microsomes (HKM; n = 8 subjects, mixed gender). Dulbecco’s modified Eagle’s medium (DMEM), Dulbecco’s phosphate-buffered saline (DPBS), and fetal bovine serum (FBS) were all purchased from Gibco (Grand Island, NY, USA), while geneticin (G418) was purchased from Seradigm (Radnor, PA, USA). BCA protein assays were purchased from Pierce (Rockford, IL, USA). LC–MS-grade methanol, acetonitrile, and ammonium formate were obtained from Thermo Fisher Scientific (Waltham, MA, USA). Acquity UHPLC BEH C18 columns (1.7 µm 2.1 × 100 mm) were purchased from Waters (Milford, MA, USA).