Retinol is an especially powerful ingredient to reduce wrinkles, but its stability depends on environmental factors such as solvent, temperature, oxygen and light. In this article we describe how its stability and skin penetration can be improved by using a triply stabilized system (TSS).
Retinol has a wide variety of biological functions such as immune reactions, epidermal differentiation, vision in vertebrates, and stimulating embryonic growth and development. It is also a prime candidate for cancer prevention.
Vitamin A is the generic name for a class of nutritionally active and unsaturated hydrocarbons. It is present in the animal kingdom as vitamin A1 (retinol) and vitamin A2 (3-dehydro-retinol), and in the vegetable kingdom as carotenoid (Figure 1).
Vitamin A2 has approximately 40% of the effect of vitamin A1, and both A1 and A2 exist in the ester form of fatty acid. Retinol contains at least one non-oxygenated beta-ionone ring with an attached isoprenoid side chain. Retinol that contains all trans double bonds in the isoprenoid side chain is the most bioactive form, however its efficaciousness declines over time because vitamin activity is decreased by isomerization, photochemical oxidation and thermal oxidation. Such degradation reactions can also reduce vitamin activity of stored and processed foods. In general, the stability of retinol and its relatives is slightly reduced in conditions of high humidity, low pH and high temperature.
Excerpt Only This is a shortened version or summary of the article that appeared in the Dec. 1, 2004 issue of Cosmetics & Toiletries magazine. The full content is not currently available online.