[Studies for analyzing the prohibited ingredients such as cyproheptadine hydrochloride in cosmetics]

Cyproheptadine hydrochloride (CH) is nominated as the prohibited ingredients in cosmetics in Japanese Pharmaceutical Affairs Act. So the analytical method for CH was investigated by HPLC. The lotion or milky lotion of 0.5 g was put into a 10-ml volumetric flask. After adding 1.0ml of CH solution at 50 microg/ml into the volumetric flask, the mixture was made up to 10ml with methanol as the test solution. Creams were procedured as follows; 0.5 g of cream was put into a 10-ml volumetric flask. After adding 1.0 ml of tetrahydrofuran into the volumetric flask, the mixture was stirred for several minutes and the ingredients of the creams were dissolved. After adding 1.0 ml of CH solution at 50 microg/ml into the volumetric flask, the mixture was made up to 10ml with methanol. This mixture was transferred to a centrifuging tube with a cap and then the tube was centrifuged for 5 minutes at 3000 rpm. The supernatant was used as the test solution. The test solution of 20 microl was analyzed by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture of 1% acetic acid with 10 mmol/l sodium octanesulfonate and acetonitrile (11:9) and the detection wavelength of 286 nm. The working curve from 0.5 to 6.0 microg/ml showed a linear line between the concentrations of CH and the peak areas. There was no interference of peak of CH with the ingredients such as methylparaben, ethylparaben in the lotions, milky lotion and creams.