Colorimetric analysis of hexachlorophene in topical formulations.

The commonly used 4-aminoantipyrine dye formation procedure for hexachlorophene analysis in topical formulations was modified to overcome interference due to other components. Bar soaps and nonemulsion formulations are analyzed directly, employing a chloroform back-extraction stage of the dye prior to quantitation. Hexachlorophene in emulsions and liquid soaps is determined using a TLC separation prior to dye formation.