QUANTITATIVE HPTLC DETERMINATION OF ELEMENTAL SULFUR IN SULFUR TOPICAL MEDICATIONS

A method was developed for determination of elemental sulfur in sulfur topical pharmaceutical preparations involving separation on a preadso rbent HPTLC silica gel plate with fluorescent phosphor, detection by f luorescence quenching, and quantification by densitometric scanning. S ulfur was directly detected and quantified on the plate at levels as l ow as 800 ng, and no interference was encountered from other ingredien ts in the medication formulations. The method was applied to the analy sis of commercial liquid and cream preparations having respective labe l values of 5% and 8% sulfur, and recoveries averaged 99.3 and 99.5%. An unknown cream medication was assayed using the method and the accur acy of the result was validated by standard addition. All analyses wer e carried out with 5 or 6 replicates to evaluate precision, and coeffi cients of variation ranged from 2-4%.