A Study to Investigate the Receptor Occupancy of SK-1405 in Healthy, Caucasian, Male Subjects

Inclusion Criteria: * Able and willing to provide written informed consent to participate in this study, as confirmed by signing the informed consent document(s). * Adult Caucasian male aged ≥20 and ≤50 years. * Body Mass Index (BMI) of ≥ 20 and ≤ 30 kg/m2. * Height ≤ 190 cm. * Subject is a non-smoker or has not smoked in the past 6 months. * Subject is considered to be in good health in the opinion of the investigator. * Subject's pre-study clinical laboratory findings are within normal range. * Subject must be willing and able to comply with all protocol requirements. Exclusion Criteria: * Use of prohibited medications as described in the study protocol. * Current known or suspected history of drug/solvent abuse. * Current known or suspected history of alcohol abuse or currently drinks in excess of 21 units per week. * Subjects who have consumed caffeine containing products within 24 hours prior to baseline PET-CT. * Any concurrent medical, surgical, or psychiatric condition that may affect the subject's ability to meet all protocol requirements during the study duration and/or any significant illness in the investigator's opinion in the 4 weeks before screening. * Participation in any other clinical study with an investigational drug/device within three months prior to the first day of dosing and after enrolment in the current study. * Subject has a positive result of HIV screen, hepatitis B screen or hepatitis C screen. * Subject has had a serious adverse reaction or significant hypersensitivity to any drug. * Subject has donated 500 mL or more of blood within the three months prior to screening. * History of neurological conditions. * Participation in a research study or other radiation exposure which in conjunction with this study would result in additional ionisation radiation exposure exceeding 10 mSv within the last year. * A contraindication for MRI, including but not limited to, MRI-incompatible pacemakers, recent metallic implants, foreign body in the eye, or other indications as assessed by a standard pre-MRI questionnaire, that preclude the subject undergoing MRI scans. * Subject has claustrophobia. * Subjects who have consumed Saint John's wort, red wine, Seville oranges, grapefruit or grapefruit juice within 7 days prior to dosing. * Subject has a partner who is either pregnant or breastfeeding for the duration of the study.