Application to Whitening Agents

The powdered samples of four complex crystals and hydroquinone only were exposed to a xenon lamp in a vacuum at 25 °C and the characteristic spectra of hydroquinone were measured. For the sample of hydroquinone only, it was found that about 30% of hydroquinone had deteriorated, whereas the hydroquinone in the complex crystals showed insignificant change. The resistivity of the complex crystals to the light exposure was clearly confirmed. 

After this, the complex of BCDAC and hydroquinone was selected, because the surfactant BCDAC has been used previously in ophthalmic solutions. First, the stability of the complex was checked when it was mixed with several ointments. The complex was mixed with hydrophilic ointment (HO), hydrophilic petrolatum (HP), white petrolatum (WP), plastibase (PB) and zinc oxide ointment (ZO). The colour value. 

Type of dyschromatosis Hydroquinone only BC DAC-hyd roq u i none complex 

These findings were registered at the Japanese Patent Office (Patent No. 3712066). The whitening creams, including the BCDAC-hydroquinone complex, have been commercialized by several companies. 

Although successful applications are currently limited, complex formation with surfactants holds great promise for further applications and is likely to be used in a variety of fields in the future. 

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