Zubia Zia, Iqbal Ahmad, Tania Mirza, Kiran Qadeer.
Clinical significance and methods of analysis of vitamin A.
Baqai J Health Sci Jan ;15(2):25-33.

Vitamin A is a group of unsaturated nutritional organic compounds, that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids, among which beta-carotene is the most important. Most compounds within the vitamin A family are soluble in fat and are essential for numerous processes within the body. Vitamin A (retinol) and derivatives play an essential role in metabolic functioning of the retina, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of carotenoids found in plants. It is enriched in the liver, egg yolk and the fat component of dairy products. It is required for normal vision, reproduction, embryonic development, cell and tissue differentiation and immune function in animals and humans. Vitamin A deficiency (VAD) is also known to be involved with different specific disease conditions such as xerophthalmia, polynephritis, keratomalacia and ulceration leading to irreversible blindness along with increased susceptibility to infections and abnormalities in reproduction. Vitamin A is sensitive to light and air and its ester forms are more susceptible to oxidation. The important analytical techniques used for the analysis of the vitamin A and its derivatives are high-performance liquid chromatography (HPLC), spectrophotometry and voltammetry. These methods have been found to be accurate and precise and have been applied successfully to the analysis of drug formulations.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com