The purpose of this study is to characterize the repeat dosing plasma profile, extent of accumulation and repeat dose pharmacokinetics of morphine, morphine-3-glucuronide, and morphine-6-glucuronide during administration of MNS075 in two different, clinically-relevant dosing schedules.

This study is an open label, randomized, two-treatment, two-period, two-sequence, single-center, crossover study comparing the pharmacokinetics, safety and tolerability of MNS075 (intranasal morphine) at doses of 7.5 mg self-administered q1h for 7 hours (8 doses) and 15 mg self-administered q3h for 9 hours (4 doses).

Inclusion Criteria:

• Healthy adult volunteers 18 years of age or older

Exclusion Criteria:

• History of alcohol, drug addiction, or substance abuse.
• Known to or suspected to be currently abusing alcohol or drugs.
• Allergy or hypersensitivity to shellfish or opioids.
• History of seizures.
• Clinically significant structural or functional abnormalities of the nose and upper airway, obstruction of the nasal passages, or mucosal lesions of the nostrils.
• Smoked or used tobacco or nicotine products in the past six months or expects to during the study.
• Positive for hepatitis B or hepatitis C or HIV antibodies.