A Safety, Tolerability, PD and PK Study in Healthy Adults

Inclusion Criteria: * Healthy as determined by a responsible physician or trained qualified designee * Males (Part A) or males and females (Part B) between 18 \& 64 years of age, inclusive. Females must be of non-childbearing * Capable of giving written informed consent Exclusion Criteria: * Clinically significant conditions, or history of fainting or syncope * Medical or psychiatric illness * Major surgery within 4 weeks of screening * Known difficulty with obtaining intravenous access * Any ophthalmologic condition that could interfere with pupillometry * History of sensitivity to any of the investigational products, or known intolerance to opioids or a history of medication or other allergy * Use of prescription or non prescription medications * History of drug abuse within 6 months of screening * Use of any illegal drug within 30 days of screening and throughout participation in the study * History of smoking or use of nicotine containing products within 3 months of screening and throughout participation in the study * Donation of blood or plasma within 4 weeks prior to dosing * Participation in a clinical trial and has received a medication within 30 days * Weight \<50 kg or BMI outside range of 18 - 32 kg/m2 * Positive for HIV antibody, hepatitis B virus surface antigen, or hepatitis C virus * If male, unwillingness to abstain from sexual intercourse with a pregnant or lactating woman and, if engaging in sexual intercourse with a female partner of childbearing potential, use a condom and spermicide, in addition to having their female partner use another form of contraception, and abstain from sperm donation * Part B Only: * Active dermatological condition or eczema on non-dominant hand. * Peripheral vascular disease * If female, of child bearing potential, pregnant or breastfeeding