Protocol Number: 92-DK-0033

Title:

Pharmacokinetics and Biodistribution of Ascorbic Acid in Healthy Human Subjects

Number:

92-DK-0033

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.

Sponsoring Institute:

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Recruitment Detail

Type: Active Accrual Of New Subjects

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): None

Eligibility Criteria:

INCLUSION CRITERIA:

Males and females ages 18-35.

Normal volunteers selected from colleges/universities who will:

Spend within a fall or spring semester (approximately 12-14 weeks) as an inpatient resident on the endocrine-metabolic ward at NIH.

Be willing to adhere an AA restricted diet for 3 weeks prior to their NIH admission as well as for the duration of the time spent in the study as an inpatient at NIH.

Have veins adequate for venipuncture and be willing to undergo venipunctures approximately twice per week.

Refrain from ingestion of any medication and cigarette smoking.

Be able to give informed consent.

EXCLUSION CRITERIA:

Subject non-compliance with restricted diet.

Pregnancy as determined by history, physical exam and urine beta-HCG.

History of diabetes mellitus, bleeding disorders, kidney stones, glucose-6-phosphate dehydrogenase deficiency, family history of hemochromatosis/iron overload.

Platelet count less than 150,000/ul blood; prothrombin time/partial thromboplastin time (PT/PTT) greater than 1 second above normal upper limit.

Positive test for exposure to human immunodeficiency virus.

Positive tests for Hepatitis B surface antigen, core antibody or surface antibody.

Special Instructions: Currently Not Provided

Keywords:

Ascorbic Acid

Pharmacokinetics

Biodistribution

Recruitment Keywords:

None

Conditions:

Healthy

Investigational Drug(s):

None

Investigational Device(s):

None

Contacts:

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793

Electronic Mail:prpl@mail.cc.nih.gov

Citations:

Clinical manifestations of ascorbic acid deficiency in man

Metabolism of (14)C and (3)H-labeled 1-ascorbic in human scurvy

New concepts in the biology and biochemistry of ascorbic acid

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