Scale-up feasibility in high-shear mixers: determination through statistical procedures.

The wet granulation scale-up of a formulation exhibiting plastic deformation behavior under compression was examined. Through experimental factorial design, the effect of solution level, mixing time, and mixer speed on granulation properties was investigated. Measurements of mean particle size, tapped density, bulk density, Carr's index, coarse-to-fine ratio, cumulative percentage, and flow rate were taken and compared among granulations. In addition, comparisons were done on the hardness of tablets made from the formulations. It was shown that the characteristics of the granulations made under different conditions were highly reproducible. The excipient system of microcrystalline cellulose and pregel starch was shown to be a very robust formulation that is resistant to changes in the scaling-up process in high-shear mixers.

Investigation of fatigue failure of S-65-HL "Super Tygon" roller pump tubing.

A failure analysis was performed on Norton S-65-HL Tygon tubing. Fatigue testing was performed on four sizes of this tubing, and essentially showed how the tubing wears out. A dynamic "life hours to failure" test, which was performed on the 3/8" internal diameter (ID) size, quantified when the tubing ruptured. Based on results of laboratory testing and the institution's clinical extracorporeal membrane oxygenation (ECMO) experience, a reasonable life expectancy for the 3/8" S-65-HL Tygon size was determined for use in this institution's neonatal ECMO system. An understanding of the expected performance of roller pump tubing-an integral component of the ECMO system-is imperative to providing safe, effective extracorporeal life support.