Water-Absorptive Properties of Selected Solids in a Lipophilic Base I

Water-absorptive properties of various combinations of starch, pregelatinized maize starch, talc, and zinc oxide dispersed in light liquid petrolatum were investigated. The suction orce and mercury rise were measured in terms of millibars with a tensiometer. The performance of these dispersions was evaluated in terms of two estimated parameters, α^ and β^, which were related to absorption rate and absorptive capacity, respectively. Water-absorptive capacity varied in a predictable way while absorption rate did not. Zinc oxide had the highest absorptive capacity. Some interaction among the powders was noted by a decrease in suction force when various ones were mixed together.