Inclusion Criteria:
1. Informed of the nature of the study, agreed to, and able to read, review, and sign the informed consent document prior to dosing.
2. Completed the IRB-approved screening process within 28 days prior to dosing.
3. Healthy male and non-pregnant female subjects between ages 18 and 55, inclusive, at the time of dosing.
4. Body mass index (BMI) between 18 kg/m2 to 32 kg/m2, inclusive, and weigh at least 60 kg.
5. Judged by the Investigator and/or designee to be in good health as documented by the medical history, physical examination, clinical laboratory assessments, and by general observations.
6. Subjects with glomerular filtration rate (GFR) of greater than or equal to 60.
7. Females of childbearing potential must be willing to practice an acceptable form of contraception, and have a negative serum pregnancy test at screening and a negative urine pregnancy test on admission to the treatment phase of the study.
8. Males must agree to practice an acceptable form of contraception.
Exclusion Criteria:
1. More than three digits absent from the hands due to congenital or accidental cause(s).
2. Reports receiving any investigational drug/product within 30 days prior to dosing.
3. Reports any personal history of substance abuse (including drug/alcohol abuse or addiction) or mental illness (e.g. major depression) within one year prior to screening visit.
4. Reports any presence or history of a clinically significant disorder involving the cardiovascular, respiratory, renal, urologic, gastrointestinal, hepatic, immunologic, hematologic, endocrine, or neurologic system(s) or psychiatric disease as determined by the Investigator.
5. Presence of any clinically significant results from laboratory tests, vital signs assessments, and electrocardiograms, as judged by the Investigator.
6. Demonstrates a reactive screen for hepatitis B surface antigen, hepatitis C antibody, or HIV antibody.
7. Reports a clinically significant illness during the 28 days prior to dosing (as determined by the Investigator).
8. Reports a history of allergic response(s) to Naltrexone or other opiates/related drugs.
9. Reports hypersensitivity to bisulfites.
10. Reports history of respiratory depression (e.g., sleep apnea).
11. Current severe hypotension (i.e., systolic blood pressure \<90 mmHg).
12. Reports current presence of acute bronchial asthma/ upper airway obstruction.
13. If subject reports a history of clinically significant allergies, including food or drug allergies, as judged by the Investigator.
14. Reports history/current condition of adrenal insufficiency.
15. Reports history/current condition of renal disease.
16. Demonstrates a positive drug screen for cotinine or history of smoking within previous six months.
17. Report history/current condition of seizures, increased intracranial pressure, brain tumor, head injuries or impaired consciousness.
18. Reports a blood donation totaling between 101 mL to 499 mL of blood within 30 days prior to dosing or subject who has donated more than 499 mL of blood within 56 days prior to dosing. All subjects will be advised not to donate blood for 30 days after completing the study.
19. Reports donating plasma (e.g., plasmapheresis) within 14 days prior to dosing. All subjects will be advised not to donate plasma for 30 days after completing the study.
20. Demonstrates, in the opinion of study staff, veins unsuitable for repeated venipuncture (e.g., veins difficult to locate, access, or puncture; veins with a tendency to rupture during or after puncture).
21. Reports known or suspected gastrointestinal obstruction including, paralytic ileus.
22. Reports difficulty fasting or consuming standardized meals.
23. Demonstrates a positive pregnancy screen (females only).
24. If, in the opinion of the Investigator, the subject is not suitable for the study.
