The Pharmacokinetics of Vitamin A in relation to its Teratogenicity in Healthy Women
The Pharmacokinetics of Vitamin A in relation to its Teratogenicity in Healthy Women
The project involved four clinical studies, investigating the various aspects of vitamin A pharmacokinetics following its administration in the three sources most commonly available to the general public i.e. animal liver, vitamin A supplements and transdermal creams. Investigated were the influence of (1) posture and previous dosing, (2) food and dosage, and (3) multiple dosing on the absorption of vitamin A and the formation of its teratogenic metabolites. A fourth study investigated the effect of transdermal vitamin A absorption in healthy women of child-bearing age.
Teratogenic concentrations were not found in any of the four studies performed. Posture, previous dosing and multiple dosing did not alter the absorption of vitamin A and the formation of its metabolites. However, the source of Vitamin A ingestion and the effect of dosing in conjunction with food were found to be of significance. Vitamin A and its metabolites levels were found to be many folds higher after vitamin A supplement dosing compared to dosing as a liver meal. Also, vitamin A supplement dosing in conjunction with a meal gave significantly faster absorption compared to dosing on an empty stomach. Long-term, high dose transdermal application of vitamin A creams resulted in negligible systemic amounts of vitamin A and its metabolites. In all four studies, it was observed that there were large inter- and intra-individual variations.
Vitamin supplements can be beneficial to the general public when used at the Recommended Daily Allowances. However, most sources of vitamin A are freely available to the general public, either as food sources or as over-the-counter products. Hence, abuse is a possibility, especially in the case of vitamin supplements.
University of Southampton
Honeywell, Richard James
89b1c3cf-ef80-42e0-97ad-9b484e0e8dc1
2001
Honeywell, Richard James
89b1c3cf-ef80-42e0-97ad-9b484e0e8dc1
Honeywell, Richard James
(2001)
The Pharmacokinetics of Vitamin A in relation to its Teratogenicity in Healthy Women.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The project involved four clinical studies, investigating the various aspects of vitamin A pharmacokinetics following its administration in the three sources most commonly available to the general public i.e. animal liver, vitamin A supplements and transdermal creams. Investigated were the influence of (1) posture and previous dosing, (2) food and dosage, and (3) multiple dosing on the absorption of vitamin A and the formation of its teratogenic metabolites. A fourth study investigated the effect of transdermal vitamin A absorption in healthy women of child-bearing age.
Teratogenic concentrations were not found in any of the four studies performed. Posture, previous dosing and multiple dosing did not alter the absorption of vitamin A and the formation of its metabolites. However, the source of Vitamin A ingestion and the effect of dosing in conjunction with food were found to be of significance. Vitamin A and its metabolites levels were found to be many folds higher after vitamin A supplement dosing compared to dosing as a liver meal. Also, vitamin A supplement dosing in conjunction with a meal gave significantly faster absorption compared to dosing on an empty stomach. Long-term, high dose transdermal application of vitamin A creams resulted in negligible systemic amounts of vitamin A and its metabolites. In all four studies, it was observed that there were large inter- and intra-individual variations.
Vitamin supplements can be beneficial to the general public when used at the Recommended Daily Allowances. However, most sources of vitamin A are freely available to the general public, either as food sources or as over-the-counter products. Hence, abuse is a possibility, especially in the case of vitamin supplements.
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Published date: 2001
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Local EPrints ID: 464514
URI: http://eprints.soton.ac.uk/id/eprint/464514
PURE UUID: 4a02038a-8f00-4a63-806b-bb08a79d7732
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Date deposited: 04 Jul 2022 23:43
Last modified: 16 Mar 2024 19:34
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Author:
Richard James Honeywell
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