Analytical and stability studies on medical cosmetics

Two simple and sensitive spectrofluorimetric (method Ι) and spectrophotometric(method ΙΙ) methods have been developed for the determination of some chloridecontaining toothpastes and panthenol-containing cosmetic preparations respectively.Method Ι is based on quantitative fluorescence quenching of (terbium-salicylate-hexamineternary complex) by fluoride which could be measured at λem/λex of 547nm/322nm. The ΔFconcentrationplot was rectilinear over the concentration range of 0.5-20 μg/ml. Method ΙΙdepends reaction of panthenol with nitrobenzoxadiazole chloride (NBD-Cl) and measuringthe absorbance of the resultant product at 480nm. The absorbance- concentration plot wasrectilinear over the concentration range of 2-20 μg/ml