The comparison of lipids between dry and wet types of cerumen.

The lipid fraction occupying about 20 to 30 per cent of the ceruminal volume was extracted by the fractionation method previously reported. The lipid fraction from the dry and wet types of cerumen collected from the Japanese children was further separated into several kinds of lipid component by silicic acid column chromatography. Identification of the respective lipid components was performed by thin layer chromatography and infrared spectrometry. The yields were as follows: total cholesterol 8-10%, triglyceride 1.4-1.8%, free fatty acid 1.2-2.2% and unidentified polar lipid 5.2-5.5%. There was no qualitative and quantitative difference in the results between the dry and wet types. Fatty acid components of the purified lipids were determined by gas chromatography. Higher amounts of stearic and linoleic acids were found in triglyceride from the dry type. Instead palmitic acid was demonstrated in the wet type. The contents of the other lipid fractions such as cholesterol esters, diglyceride and monoglyceride were almost equal in both types of cerumen.