November 1999

In part I, Hinshaw described a simple experiment with coins to explain the statistical nature of separations and to impart a better understanding of the physical processes inside the column. In part II, he compares this coin-toss simulation with chromatographic columns and describes differences between the analogy and real-world situations.

Displacement chromatography is a viable alternative to elution chromatography, but the biotechnology industry has yet to fully exploit this technique. The authors present results of a pilot-scale ion-exchange displacement process developed for the removal of variants from recombitant human brain-derived neutrotrophic factor.

Krull and Swartz examine validating cleaning methods for pharmaceutical manufacturing equipment and look at general requirements and specific cleaning procedures, sampling types, and analytical methods.