This study is to evaluate the safety and tolerability of single dose of GB-5001 (donepezil) IM depot in healthy male volunteers. And, it is to predict the multiple-dose pharmacokinetics based on the single-dose pharmacokinetics of GB-5001 IM depot and the oral Aricept® (donepezil hydrochloride) tablet by PK modeling.

Inclusion Criteria:

• Healthy, non-smoking male volunteers, 18-55 years of age, inclusive at the time of informed consent.
• Body mass index (BMI) that is within 18.5 - 30.0 kg/m2, inclusive, and weight at least 55 kg and above.
• Healthy, according to the medical history, ECG, vital signs, laboratory results and physical examination as determined by the PI/Sub-Investigator.
• Systolic blood pressure between 95-140 mmHg, inclusive, and diastolic blood pressure between 55-90 mmHg, inclusive, and heart rate between 60-100 bpm, inclusive, unless deemed otherwise by the PI/Sub-Investigator.
• Clinical laboratory values within the clinical site's most recent acceptable laboratory test range, and/or values are deemed by the PI/Sub-Investigator as "Not Clinically Significant".

Exclusion Criteria:

• Known history or presence of any clinically significant hepatic, renal/genitourinary, gastrointestinal, cardiovascular, cerebrovascular, pulmonary, endocrine, immunological, musculoskeletal, neurological, psychiatric, dermatological or hematological disease or condition unless determined as not clinically significant by the PI/Sub-Investigator.
• Known history or presence of seizure or convulsion, unless determined as not clinically significant by the PI/Sub-Investigator.
• Known history or presence of peptic ulcer or gastrointestinal bleeding within 3 months prior to study drug administration, unless determined as not clinically significant by the PI/Sub-Investigator.
• Known risk of developing ulcers (for example, if you are taking non-steroidal anti-inflammatory drugs [NSAIDS] or high doses of acetylsalicylic acid [ASA] [Aspirin®]), unless determined as not clinically significant by the PI/Sub-Investigator.
• Clinically significant history or presence of any clinically significant gastrointestinal pathology (e.g., chronic diarrhea, inflammatory bowel disease), unresolved gastrointestinal symptoms, or other conditions known to interfere with the absorption, distribution, metabolism, or excretion of the drug experienced within 7 days prior to study drug administration, as determined by the PI/Sub-Investigator.
• Presence of any clinically significant illness within 30 days prior to dosing, as determined by the PI/Sub-Investigator
• Presence of any clinically significant illness within 30 days prior to dosing, as determined by the PI/Sub-Investigator.