D glucuronic acid

All reagents used were of analytical grade. All solutions were prepared using ultra-high pure (UHP) 18 Ω water. All laboratory ware was soaked for 24 h in an acid bath containing 10% (v/v) nitric acid and then rinsed with UHP water. Concentrated hydrochloric acid (12 mol L⁻¹), HNO₃ 69%, NaCl, NH₄Cl, anhydrous Na₂SO₄, CaCl₂.2H₂O, NaHCO₃, anhydrous D ( + )-glucose, sodium arsenate dibasic heptahydrate, cadmium acetate and lead acetate trihydrate were obtained from Fisher Scientific. d-glucuronic acid, Pancreatin (pig), pepsin (pig), Bovine serum albumin (BSA), KSCN, NaH₂PO₄, mucin (pig), D-glucosamine hydrochloride, lipase (pig), α-amylase (Bacillus species), urea and bile salts (bovine), modified eagle medium (DMEM) containing 4.5 g/L glucose, penicillin-streptomycin solution (10, 000 units penicillin and 10 mg streptomycin per mL), and Hank’s Balanced Salt Solution (HBSS) and glycine were obtained from Sigma–Aldrich (St. Louis, MO, USA). KH₂PO₄, MgCl₂·6H₂O, KCl, and uric acid were obtained from VWR. Caco-2 cells (HTB-37™) were purchased at passage 18 from the American Type Culture Collection (ATCC, Manassas, VA, USA). Fetal bovine serum and trypsin-EDTA were purchased from Invitrogen (Burlington, ON, Canada).