This study will be to compare the pharmacokinetics of nalmefene administration intranasal with and without an absorption enhancer compared to an intramuscular injection.

This study will be an inpatient, double-blind, randomized, crossover study involving 14 healthy volunteers. Each subject will receive 4 treatments during the 4 dosing periods.Subjects will stay in the inpatient facility for 17 days to complete the entire study and be discharged following completion of discharge procedures at the end of the last period. Subjects will be called 3 to 5 days after discharge to inquire concerning adverse events and concomitant medications since discharge. After obtaining informed consent, subject will be screened for eligibility. ON the day after clinic admission, subjects will be administered the intranasal-formulated drug in randomized order with 4 days between doses; the intramuscular dose will be administered during the fourth (last) treatment period.

Inclusion Criteria:

• Males and females 18 to 55 years of age
• Provide written informed consent
• Body Mass index (BMI) ranging from 18 to 32 kg/m2
• Adequate venous access
• No clinically significant concurrent medical conditions
• Males subjects must agree to use an acceptable method of birth of contraception with female partners as well as not to donate sperm throughout the study and for 90 days after the last study drug administration
• Female subjects of child bearing potential must agree to use an acceptable method of birth control from the start of screening until 30 days after completing the study. Oral contraceptives are prohibited
• Agree not to ingest alcohol, drinks containing xanthine >500 mg / day (e.g., Coca Cola, tea, coffee, etc.), or grapefruit/grapefruit juice or participate in strenuous exercise 72 hours prior to admission through the last blood draw of the study

Exclusion Criteria:

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