Coadministration of tacrolimus and mycophenolate mofetil is frequent in kidney transplantation. Due to narrow therapeutic range of tacrolimus and mycophenolate mofetil, therapeutic drug monitoring with dose adjustment is required. Investigating pharmacokinetic interplay between two drugs enables fine dose adjustment, while mechanism of drug interaction between two drugs is still not well understood. Therefore, an open-label, three period, single dose trial is planned to investigate the drug interaction between tacrolimus and mycophenolate mofetil.

Study consists of three periods with fixed sequence: 1) single dose of mycophenolate mofetil 1,000mg; 2) single dose of tacrolimus 5mg; 3) single dose of mycophenolate mofetil 1,000mg and tacrolimus 5mg. All subjects have one week of washing period between single dose administration. Blood samples are drawn up to 72 hours after drug administration. Single nucleotide polymorphisms known to result in pharmacokinetic variability of study drug are also investigated. Drug interaction is going to be assessed through the ratio of area under the concentration curve of one drug in the presence or absence of another drug.

Inclusion Criteria:

• Male adult with age of 19-45
• Weight difference between ideal and actual body weight is less than 20%
• Previous healthy with no known disease
• Considered normal on physical exam, clinical laboratory tests(complete blood count, electrolyte, renal and hepatic function) and electrocardiogram
• Never been heavy-drinker within one month prior to trial initiation and able to abstain from alcohol during trial

Exclusion Criteria:

• Ever smoked within one year prior to trial initiation
• Took other drugs (including herbal medicine) within one month prior to trial initiation
• Alcohol or drug abuser
• Participated another clinical trial within three months
• Considered inadequate under investigator's discretion