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Publication Citation: Microliter capillary viscometer

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Author(s): Steven D. Hudson; Prasad S. Sarangapani; Kalman D. Migler; Jai A. Pathak;
Title: Microliter capillary viscometer
Published: Date Unknown
Abstract: Current trends require protein therapeutics to be highly concentrated, posing challenges for solution stability and syringeablity, since viscosity depends on protein clustering and rises markedly with concentration. Convenient viscometry is therefore necessary for evaluation of product formulation, manufacturing processes and drug stability. Here we report the development of a new capillary viscometer and methodology that addresses major needs of the pharmaceutical industry: a.) small volumes (< 100 microliters) (for convenience and to conserve precious fluids), b.) a wide range of shear rates (for rates are fast in injection and intermediate in manufacture, and slow shearing is most sensitive to clustering), and c.) no air interface (to test surfactant free solutions, where protein adsorption contributes stress). A glass micropipette (or microfluidic device) is the test channel, and viscosity is measured with an accuracy and precision of a few percent. To measure a two-decade span in shear rates, the test requires approx. 3 microliters of fluid and 7 minutes of time. The test can then be repeated at different temperatures (ranging approximately (0 ‹ 80) °C. Using these features of temperature control and variable shear rate, we demonstrate a transition between Newtonian and non-Newtonian viscosity in a solution of self-associating monoclonal antibody. This viscometer meets industry needs and is easy to use. The concept can be adapted for high-throughput use with a multi-well plate.
Citation: Biomicrofluidics
Keywords: viscosity; microfluidics; microliter; protein solution; monoclonal antibody
Research Areas: Complex Fluids