Spreadability Using Force and Under Normal Gravity

SPREADABILITY USING FORCE AND UNDER NORMAL GRAVITY 

A master curve of the rheological conditions applicable during spreading of lipophilic preparations with force on the skin using a method similar to that of Wood (1968) showed that the range of acceptable apparent viscosity was about 3.9 poise to 11.8 poise, with an optimum value of approximately 7.8 poise (Barry and Grace, 1972). The preferred region was approximately bounded by shear rates 400-700 s and shear stress 2,000-7,000 dyne cm (200-700 Pa, respectively). 

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