<qa>  What is the double-blind, single ascending dose administration study?This is a double-blind, single ascending dose administration study of four doses of CTP-499. Following dosing safety and tolerability will be assessed. Blood and urine samples will be taken for pharmacokinetics PK and bioavailability. Safety assessments will include monitoring of adverse events, vital signs blood pressure, pulse rate, respiratory rate and oral temperature, clinical laboratory findings, 12-lead ECGs, and physical examination findings. 