Factors affecting the statistical parameters and patterns of distribution of residual moistures in arrays of samples following lyophilization
Greiff, D.
Journal of Parenteral Science and Technology a Publication of the Parenteral Drug Association 44(3): 118-129
1990
ISSN/ISBN: 0279-7976 PMID: 2370621 Document Number: 365141
Numerous studies were undertaken to examine in depth the statistical parameters (mean, standard deviation, standard error of the mean, etc.) and the distributions of residual moistures of 3 mL samples of 2% albumin arranged in a 22 .times. 10 grid of samples (the array) and dried by sublimation of ice in vacuo. Because of the relatively large numbers of selected samples used for the determination of the patterns of distribution of residual moistures, it was necessary to develop a modified gravimetric method for measuring residual moistures. In the majority of circumstances, with the vials containing the samples positioned on a base defined by cartesian coordinates (x, y) and the contents of residual moistures measured on an axis perpendicular to the base (z), the distributions of contents of residual waters were described best by the equation for a 2-nd order polynominal. It was found that the contents of residual moistures of individual vials were "position oriented: and not "vial associated." It was found that the statistical parameters and patterns of distributions of residual moistures were dependent on: (1) the orientation of openings in the split stoppers used for freeze-drying, (2) the shelf of the freeze-drying apparatus (top, middle, bottom) upon which the vials were placed, and (3) alterations in elapsed times and shelf temperatures.