Application Note: Pharmaceutical Ointments

Pharmaceutical ointments are engineered to have rheological properties important to the physical performance of the product when used by the consumer. Most ointments are intended to be thick when standing to prevent them from flowing away from the intended area of use. High viscosity at near zero shear rate characterizes this behavior; determining the yield stress value quantifies this desired property. Ointments are also engineered to be easy to apply when rubbed. This is known as shear thinning behavior. Both characteristics of yield and shear thinning can be easily characterized using only a small volume of sample with a Wells-Brookfield Cone/Plate viscometer or rheometer.