Determination of sodium dodecyl sulfate in hydrophilic ointments by thin-layer chromatography with flame ionization...

Thin-layer chromatography with flame ionization detection (TLC-FID) was compared with colorimetric and HPLC methods for measuring sodium dodecyl sulfate (SDS), an anionic surfactant, in hydrophilic ointments prepared according to the Japanese Pharmacopoeia, the United States Pharmacopoeia and British Pharmacopoeia. The TLC-FID method was found to be better than the colorimetric method in terms of simplicity and accuracy in the determination of SDS in hydrophilic ointments. Quantification of a small amount of SDS was not possible using HPLC with refractive index detection due to the low sensitivity of the detector.