Creatinine d3

Rats were administered clinical grade Vancomycin hydrochloride (Lot number: 167973; Fresenius Kabi, Lake Zurich, IL, USA), piperacillin-tazobactam sodium (Lot number: 1PU19022; Apollo, Palm Beach Gardens, USA), iohexol [Omnipaque] (Lot number: 15025174; GE Healthcare Inc., Marlborough, MA, USA), and normal saline as a control group (Hospira, Lake Forest, IL, USA). Vancomycin and piperacillin-tazobactam were prepared by weighing and dissolving the powder in purified water (EMD Millipore, Burlington, MA) to achieve final concentrations of 100 mg/mL and 500 mg/mL, respectively. For LCMS analyses, analytical grade iohexol (Lot number: LRAC5648; Sigma-Aldrich, St. Louis, MO), and creatinine (Lot number: LRAB2988; Sigma-Aldrich, St. Louis, MO) were purchased for stock solution preparation; iohexol-d5 (Lot number: LRAC5648; Cayman Chemical, Ann Arbor, MI), and creatinine-d3 (Lot number: 0533175–29; Cayman Chemical, Ann Arbor, MI) were purchased for use as internal standards; LCMS-grade acetonitrile and methanol (VWR, Radnor, PA) were used as mobile phase solvents; formic acid was obtained from Fischer Scientific (Waltham, MA). Frozen, nonimmunized, nonmedicated, pooled plasma (anticoagulated with disodium EDTA) from Sprague Dawley rats (Lot: RAT483100; BioreclamationIVT, Westbury, NY) was utilized for dilution of rat plasma samples.