The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes
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A Desai1, G E Peck, J E Lovell
1Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907.
Pharmaceutical Research
|October 1, 1993
Abstract:
The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.