Double-Blind Randomized Crossover Trial to Access Electrocardiogram Effects of HPN-100

Inclusion Criteria: * Must be in good health * Negative hepatitis panel and negative HIV antibody screens * Females must be non-pregnant, non-lactating, and either postmenopausal or agree to to use adequate contraceptive methods throughout the study * Males must either be sterile or willing to use adequate contraceptive methods throughout the study * Willing and able to comply with all trial requirements * Able to comprehend and willing to sign an Informed Consent Form (ICF) Exclusion Criteria: * History or clinical manifestations of significant allergic, metabolic, hepatic, renal, endocrine, hematological, pulmonary, cardiovascular, gastrointestinal, urological, neurological, or psychiatric disorders * History of hypersensitivity or allergies to any drug compound * History of stomach or intestinal surgery or resection * History or presence of an abnormal ECG * History of alcoholism or drug addiction within 1 year * Use of any tobacco-containing or nicotine-containing products within 3 months * Participated in any other clinical trial of an investigational drug (or a medical device) within 30 days * Use of any prescription medications/products other than contraceptives within 14 days * Use of any over-the-counter, non-prescription preparations (including vitamins, minerals, and phytotherapeutic/herbal/plant-derived preparations) within 7 days * Test positive for drug(s) of abuse, ethanol, or cotinine * Have donated blood or blood components within 30 days * Have received blood products within 2 months * Have a history of unexplained syncope * Have a family history of unexplained sudden death