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Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations
Author(s) -
Ahmad I.,
Ali Sheraz M.,
Ahmed S.,
Shad Z.,
Vaid F. H. M.
Publication year - 2012
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/j.1468-2494.2012.00708.x
Subject(s) - tartaric acid , chemistry , boric acid , dehydroascorbic acid , reaction rate constant , ascorbic acid , citric acid , nuclear chemistry , photodegradation , kinetics , medicinal chemistry , organic chemistry , catalysis , food science , physics , quantum mechanics , photocatalysis
Synopsis This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH 2 ) in oil‐in‐water cream formulations exposed to the UV light and stored in the dark. The apparent first‐order rate constants (0.34–0.95 × 10 −3 min −1 in light, 0.38–1.24 × 10 −2 day −1 in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second‐order rate constants (0.26–1.45 × 10 −2 M −1 min −1 in light, 3.75–8.50 × 10 −3 M −1 day −1 in dark) for the interaction of AH 2 and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH 2 both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH 2 in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH 2 ‐excited triplet state by CT and TA and by the inhibition of AH 2 degradation through complex formation with BA. AH 2 leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations.