Relative humidity: It is a ratio, expressed in percent, the amount of atmospheric moisture present relative to the amount that would be present if the air is saturated. Since the later amount is dependent on temperature. Relative humidity is a […]
SETTLING IN SUSPENSIONS : One aspect of physical stability in pharmaceutical suspensions is concerned with keeping the particles uniformly distributed throughout the dispersion. It possible to prevent settling completely over a prolonged period of time, it is necessary to consider the […]
WETTING OF PARTICLES: The initial dispersion of an insoluble powder in a vehicle is an important step in the manufacturing process and requires further consideration. owders sometimes are added to the vehicle, particularly in large-scale operations, by dusting on the […]
The term ‘rheology’ was derived from the Greek words rheo (flow) and logos (science) and is used to describe the flow of liquids and the deformation of solids. Viscosity is an expression of the resistance of a fluid to flow: […]
Thixotropy: Thixotropy is defined as the progressive decrease in viscosity with time for a constant applied shear stress followed by a gradual recovery when the stress is removed. Thixotropy is a time-dependent shear thinning property. Thixotropy can be defined as […]
STABILITY OF COLLOIDAL SYSTEMS: Colloidal particles undergo frequent collisions as a result of Brownian motion. Whether these collisions result in coagulation (permanent contact or close aggregation of particle), flocculation (temporary contact or large aggregates) or whether the particles rebound and […]
A disperse system is defined as a heterogeneous two-phase system in which the disperse phase is distributed as particles or droplets throughout another phase called as dispersion medium. Based on the size of dispersed particles within the dispersion medium, the […]