Model solutions of certified dyes (FD&C Blue No. 2, FD&C Yellow No. 5, and FD&C Yellow No. 6) were exposed, alone or with added selected excipients, in a fadeometer to accelerate light-induced color fading. At predetermined intervals, the solutions were tested spectrophotometrically. The method is a valuable rapid screening technique for predicting the comparative light stability of dyes used in pharmaceutical formulations.
Keyphrases Colorants, FD&C Blue No. 2, FD&C Yellow No. 5, and FD&C Yellow No. 6-rapid evaluation of effect of excipients on color fading 0 Certified dyes-effect of excipients on color fading, method for evaluation Dyes, certified-effect of excipients on color fading, method for evaluation Coloring agents have been used in medicine since ancient times to achieve a more attractive appearance. Recently, colors have become even more important in pharmaceuticals due to the necessity of rapid product identification. Natural dyes, usually obtained from the plant or animal kingdom, were gradually replaced in modern medicine by synthetic products with well-defined stability and uniformity. However, many artificial coloring agents previously permitted for foods and pharmaceuticals were recently eliminated or their use was severely restricted because of intensive research showing carcinogenesis or teratological damage in animals when massive doses of the coloring agents were used. "Martindale's Extra Pharmacopoeia" (1) lists 39 synthetic coloring agents used in food products. The size of this list, however, is sharply reduced if one selects only those approved in most industrialized countries, because the legislation regulating colorants varies widely. Only three synthetic coloring agents are almost universally accepted (2): FD&C Yellow No. 5, FD&C Yellow No. 6, and FD&C Blue No. 2. The objective of this study was to develop a rapid screening meth-Table I-Composition of Sample Solutions