Padimate A is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
that is an ingredient in some
sunscreen
Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn and ...
s. It is an
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
derivative of
PABA. This aromatic chemical absorbs
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
rays thereby preventing sunburn. However, its chemical structure and behaviour is similar to an industrial free radical generator.
In Europe this chemical was withdrawn in 1989 for unstated reasons.
In the US it was never approved for use in sunscreens.
Photobiology
The photobiological properties of padimate O and padimate A resemble that of
Michler's ketone
Michler's ketone is an organic compound with the formula of CH3)2NC6H4sub>2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a photosensitize ...
. These compounds have been shown to increase the lethal effects of UV-radiation on cells.
This photochemistry is relevant to the
sunscreen controversy
Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn and ...
.
See also
*
Padimate O
Padimate O is an organic compound related to the water-soluble compound PABA (4-aminobenzoic acid) that is used as an ingredient in some sunscreens. This yellowish water-insoluble oily liquid is an ester formed by the condensation of 2-ethylhex ...
, a related sunscreen ingredient
References
4-Aminobenzoate esters
Sunscreening agents
{{dermatologic-drug-stub