shown). The pH of CHA increased whereas
CRW decreased, which may be due to the
effect of heat to the substances. The viscosity
of all creams was almost unchanged except
at 45°C and heating/cooling condition
(Table 3), which may be due to heat effect.
The heat affected to pH and viscosity but
not the physical appearances, therefore, the
CHA and CRW should not be stored at high
temperature for long period. Regarding the
pH and viscosity of the sample after heating/
cooling condition, the CHA0.3 and CRW0.3
were likely to be more stable than the CHA0.5
and CRW0.5 creams. Therefore, CHA0.3 and
CRW0.3 were selected for further study