The purpose of this study is to measure the amount of MMF and tacrolimus concentration in the blood at a given time. Currently MMF is ordered as a set dose and tacrolimus is given based on body weight. While the deceased donor transplant receives the complete liver, in the live donor just over half of the liver is given (about 60%). The way these different types of transplants break down drugs could be different. Measuring the drug levels allows us to know what happens to the medication in between the morning and the evening dose.

The purpose of this study is to measure the amount of MMF and tacrolimus concentration in the blood at a given time. Currently MMF is ordered as a set dose and tacrolimus is given based on body weight. While the deceased donor transplant receives the complete liver, in the live donor just over half of the liver is given (about 60%). The way these different types of transplants break down drugs could be different. Measuring the drug levels allows us to know what happens to the medication in between the morning and the evening dose.

12 subjects with live liver donors and 12 subjects with deceased donors will be included in the study.

Each patient will have 12 (twelve) blood samples (half a teaspoon) drawn at 0,1, 2, 3, 4, 4½; 5, 6, 7, 8, 10 and 12 hours from an intravenous line placed during the operation. At the same time, 24-hour urine will be collected to measure your kidney function. After 4 to 6 days post transplant when the will be switched to oral MMF, again 10 (ten) blood samples a half teaspoon each will be drawn at 0, 1, 2, 3, 4, 5, 6, 8, 10, 12 hours. Blood will be drawn with the routine daily blood work for the first 14 days and then at 1 and 3 months after transplant. Total blood drawn over 3 months will be about 7 tablespoons. A 24-hour urine will be collected in a container given to you starting one day before the routine clinic visit (as a standard of care). The 24-hour urine will be collected at 1 and 3 months after transplant as well.

If a woman, who could become pregnant, a pregnancy test will be done before your transplant. They would also have to use birth control during the study period and 6 months after the completion of study.

Inclusion Criteria:

• Adult
• Female patients
• Negative pregnancy test
• Willing for contraception during the study period and 6 weeks after study

Exclusion Criteria:

• Serum Creatinine > 2.5 mg/dl
• On Dialysis
• HIV +ve
• Re-transplantation
• On Ventilator
• Multi-organ Transplant
• Platelets < 50,000
• WBC < 2,500