Study to Evaluate the Effects of 90 mg Intravenous Infusions of GC4419 on the Single Dose Pharmacokinetics of Dextromethorphan in Healthy Adult Subjects

Inclusion criteria

• Male or female, non-smoker, ≥ 18 and ≤ 55 years of age, with BMI > 18.5 and < 30.0 kg/m2 and body weight ≥ 50.0 kg for males and ≥ 45.0 kg for females.
• Healthy as defined by:

• the absence of clinically significant illness and surgery within 4 weeks prior to dosing.
• the absence of clinically significant history of neurological, endocrinal, cardiovascular, pulmonary, hematological, immunologic, psychiatric, gastrointestinal, renal, hepatic, and metabolic disease.
• Females of childbearing potential must be willing to use acceptable contraceptive method throughout the study and for 30 days after the last study drug administration:
• Male subjects must be willing to use acceptable contraceptive method from the first dosing until at least 90 days after the last study drug administration:
• Male subjects (including men who have had vasectomies) with a pregnant partner must agree to use a condom from the first dosing until at least 90 days after the last study drug administration.
• Male subjects must be willing not to donate sperm until 90 days following the last study drug administration.
• Capable of consent.
• Consent to perform genotyping for CYP2D6.

Exclusion criteria

• Any clinically significant abnormality at physical examination, clinically significant abnormal laboratory test results
• Positive urine drug screen or urine cotinine test at screening.
• History of allergic reactions to GC4419, DM, or other related drugs.
• Use of any drugs known to induce or inhibit hepatic drug metabolism within 30 days prior to the first DM administration.
• Poor CYP2D6 metabolizers as determined by genetic testing.
• Positive pregnancy test at screening.
• Any reason which, in the opinion of the Principal Investigator, would prevent the subject from participating in the study.
• Clinically significant ECG abnormalities or vital sign abnormalities
• History of significant alcohol abuse within one year prior to screening or regular use of alcohol within six months prior to the screening visit
• History of significant drug abuse
• Participation in a clinical research study involving the administration of an investigational or marketed drug or device within 30 days prior to the first dosing, administration of a biological product in the context of a clinical research study within 90 days prior to the first dosing, or concomitant participation in an investigational study involving no drug or device administration.
• Use of medication other than hormonal contraceptives and topical products without significant systemic absorption:
• Donation of plasma within 7 days prior to dosing.
• Breast-feeding subject.