Abstract
The applied weight of an ointment or cream can influence its effects. In addition, the bases and formulations of an ointment or cream can have an impact on the applied weight. However, little is known about the tem perature effects on the applied weight, and few investigations of this effect have been reported. In order to evaluate the relationship between temperature and stretchiness or applied weight, we conducted experiments at 1°C or 30°C using a spread meter and healthy subjects. The stretchiness of oleaginous ointment bases was significantly increased by 2 times with a rise of temperature from 1°C to 30°C, and the yield values were decreased dramatically. The applied weights of oleaginous ointment bases were increased about 2 times with the rise of temperature. The stretchiness and applied weights of water-in-oil (W/O)-type emulsion bases were increased as well. In contrast, the yield values of water-soluble ointment bases and oil-in-water-type emulsion bases were decreased slightly, and applied weights were not changed. These results suggest that we should consider the change of stretchiness and applied weights of oleaginous ointment bases and W/O-type emulsion bases with changes in temperature in compliance instructions.
