Single Dose PK of IV Tedizolid Phosphate in Morbidly Obese and Non-Obese Adults

Subjects will present to the clinical research unit in the morning (approximately 6:30 a.m.) of the dosing day. A urine pregnancy test will be performed to rule out pregnancy prior to administration of the tedizolid phosphate dose to female subjects. The subject's height, total body weight, and vital signs (heart rate, blood pressure, temperature, and respiratory rate) will be recorded. Subjects judged (by study physician) to be healthy enough to participate will proceed with the study procedures.

An 18-20 gauge intravenous peripheral catheter will be inserted into the antecubital vein or a vein in the fore-arm of the non-dominant arm for sequential blood sampling, and an initial predose blood sample (5 mL) will be collected. A minimum of 3-5 mL of blood is required per pharmacokinetic sampling time-point. Each blood collection tube will be pre-labeled with: 1.) study protocol number; 2.) subject study number; 3.) date of collection; 4.) time-point. A 0.9% Sodium Chloride infusion may be run through the peripheral line at 30 to 40 mL per hour to maintain catheter patency for the 12 hour sampling phase. Alternatively, a heparin lock technique will be utilized to maintain intravascular catheter patency.

A single-dose of tedizolid phosphate will be administered as an intravenous infusion (250 mL normal saline) over 1 hour (~8:00 a.m.). The intravenous administration tubing will be flushed with 0.9% Sodium Chloride infusion at 250 mL per hour (to match the tedizolid phosphate rate of infusion) for 10 minutes to ensure complete dose delivery. Blood samples (5 mL) will be collected 0.5 (middle of infusion), 1 (end of infusion), 2, 4, 6, 8, 12, 24, 48, and 72 hours post dose in blood collection tubes. The plasma will be harvested (centrifugation at 4°C) within 60 minutes of collection and stored at -70°C as two aliquots until analysis. The intravascular catheter "dead-space" volume will be discarded prior to blood sample collection by withdrawing 1.5-2 mL from the catheter to ensure no unintentional sample dilution. The intravascular catheter will be removed after the 12 hour sample and the subject will be discharged from the research unit. The subject will return to the research unit for blood sample collection on a daily basis at the following points: 24 (Visit 3), 48 (Visit 4), and 72 hours (Visit 5) after the dose via a peripheral vein needle stick. The exact date and time of blood sample collection will be recorded on case report forms. Each blood sample tube will be inverted and made up-right 5 times to afford mixing of blood with the anticoagulant. Blood samples will be maintained on wet ice and centrifuged at 1200 g for 10 minutes at 4°C within 60 minutes of collection to yield approximately 2 mL of plasma per 5 mL blood collection. The plasma samples will be transferred from the -20°C freezer for storage at -70°C at the end of the sample collection period until analysis.

Inclusion criteria

• Non-smoking or light-smoking (≤ 5 cigarettes per day) volunteers
• Estimated CLcr (Cockcroft-Gault equation) ≥ 90 mL/min
• Female subjects of childbearing potential (CBP) either surgically sterilized, using hormonal contraceptives or an effective barrier method of contraception (diaphragm, cervical cap, condom) or agree to abstain from sex from the time of pre-study screening, during the entire study period and 4 weeks following the study period
• Platelets count ≥ 140,000/mL
• Absolute neutrophil count (ANC) ≥ 1800/mL

Exclusion criteria

• History of hypersensitivity reaction to any oxazolidinone
• BMI < 18.5 kg/m2
• Any chronic medical condition requiring pharmacologic therapy
• Transaminases (AST or ALT) > 2.5 x upper limit of normal
• Total bilirubin > 1.5 x upper limit of normal
• Positive urine pregnancy test (if female)
• Abnormal electrocardiogram (ECG) as judged by the study physician
• Unable to tolerate venipuncture and multiple blood draws
• Clinically significant abnormal physical examination defined as a physical finding requiring further clinical work-up
• Unable to independently provide a written informed consent