This study assess the drug concentration of metformin in healthy adult volunteers according to the sampling method.

Inclusion Criteria:

• Healthy male subjects who, at the time of screening, are the age of older than 19 years
• Subjects who have BMI more than 17.5kg/m2 and less than 30.5kg/m2 and body weight more than 55kg
• There is no congenital disease or within 3 years of chronic diseases
• Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and pulse rate measurement, ECG or clinical laboratory tests
• Subjects who signed and dated the informed consent form(approved by IRB) after understanding fully to hear a detailed explanation in the clinical trial

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease
• A subject with any history of gastrointestinal disease (e.g., Crohn's disease, acute or chronic pancreatitis, and others) and surgery (except for simple appendectomy or repair of a hernia), which can influence the absorption of investigational products
• A subject who has the following clinical laboratory test results Liver Function Test (AST, ALT) > two times the upper limit of the normal range
• History of regular alcohol consumption exceeding 210g/week(12g = 125 mL of wine, 10g = 250 mL of beer, 10g = 50 mL of hard liquor) within 6 months of Screening
• A subject who has participated in any other clinical trials and had medication within 3 months prior to the first administration of investigational product.
• A subject with a history of drug abuse or a positive urine drug screening for drug abuse within 1 year
• A subject who has taken the drugs that induce and suppress drug- metabolizing enzymes within 30 days prior to investigational product administration
• A smoker who consumes more than 20 cigarettes/day within 6 months
• A subject who has taken any ethical-the-counter drug or has taken any over- the-counter drug within 10 days before the investigational product administration
• A subject who has donated whole blood within 2 months or blood components within 1 month prior to the investigational product administration
• Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation