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The Body's Affect on Vitamin C
Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Summary
Pharmacokinetics is the term used for how the body affects a drug once it is taken. Vitamin C, also known as ascorbic acid, is an essential water soluble vitamin. Meaning, the body does not make Vitamin C it must be taken in through the diet. In this study researchers will attempt to determine how the amount of water consumed affects the level of vitamin C in the blood (specifically the plasma component of the blood). In this study researchers will take 13 subjects and place them on a Vitamin C restricted diet. Vitamin C levels will be measured twice a week on an outpatient basis until all subjects reach a desired low level of Vitamin C (12-15 micromolar plasma ascorbic acid concentration). Subjects will then be admitted and undergo 24 hour blood and urine collection. Following the collection of samples, subjects will then begin to receive Vitamin C orally (by mouth) and intravenously (injected into the vein). The dosage of Vitamin C will gradually increase from 30 mg-2500 mg divided into two daily doses. Blood and urine samples will be collected each time the dose is increased. The study will take approximately 18 weeks after which the subjects will be discharged in healthy condition.
Official title: Pharmacokinetics and Biodistribution of Ascorbic Acid in Healthy Human Subjects
Key Details
Gender
All
Age Range
18 Years - 35 Years
Study Type
INTERVENTIONAL
Enrollment
23
Start Date
1997-01-23
Completion Date
2019-03-04
Last Updated
2026-06-16
Healthy Volunteers
No
Conditions
Interventions
Vitamin C
Outpatient subjects will be encouraged to consume vitamin C in foods. As inpatients, vitamin C deficiency will be induced by placing subjects on a tightly restricted scorbutic diet. Plasma vitamin C will be monitored several times per week. When subjects have achieved a plasma ascorbate concentration of 5-10 micromolar, blood sampling and urine collection over 24 hours will be performed. After platelets and leukocytes are collected, ascorbate repletion will begin. Escalating doses of ascorbate will be administered orally and intravenously for the remainder of their inpatient admission. Total daily doses of 30mg, 60mg, 100mg, 200mg, 400mg, 1000mg and 2500mg will be given in two divided doses. Bioavailability of ascorbate will be determined at each dosage increment. When plasma ascorbate concentration reaches steady state for each dose, subjects will undergo 36 hr plasma sampling and a timed 48 hr urine collection.
Locations (1)
National Institutes of Health Clinical Center
Bethesda, Maryland, United States