Fully Understand Your Excipient's Characteristics

In this application note, viscosity profiles as a function of temperature were previously presented for Poloxamer 407 (Lutrol^® F 127) solutions at multiple concentrations. (What is a poloxamer?) The dependence of viscosity on temperature deviated from the simple Arrhenius law obeyed by many simple fluids and exhibited a maximum.  To fully characterize this complex fluid, shear rate sweeps were performed at multiple temperatures along the profile.  The behavior was shear thinning in the peak region and Newtonian or independent of shear rate at the lowest viscosity values.  The microstructural changes that occur with temperature do not simply shift the viscosity values but also produce a Non-Newtonian response.