[Studies for analyzing prohibited ingredients such as estriol in cosmetics].

Estriol (EO) is nominated as the prohibited ingredients in cosmetics in Japanese Pharmaceutical Affairs Act. So the analytical method using HPLC for EO was investigated. After placing 1.0 ml of EO solution at 50 microg/ml and 0.5 g of the lotion into a 10-ml volumetric flask, the methanol was added to make until that volume and this solution was used as the testing solution. Milky lotion was procedured as follows: After placing 1.0 ml of EO solution at 50 microg/ml and 0.5 g of the milky lotion into a 10-ml volumetric flask, the methanol was added to make until that volume. The suspending mixture was moved to a centrifuging tube with a cap. After centrifuging at 3000 rpm for 5 minutes, the supernatant was used as the testing solution. The testing solution of 20 microl was determined by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture of water and acetonitrile (31:9) and the detection wavelength of 285 nm. The working curve from 1.0 to 6.0 microg/ml showed a linear line between the concentrations of EO and the peak area. There was no interference of peak of EO from the lotion and milky lotion.