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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.

The study described herein was undertaken to simultaneously optimize the composition of tablet and capsule formulation of an insoluble experimental drug, and to learn more about the effect of the interaction between the ingredients on the basic properties of the final dosage form. Four independent variables were varied in a set of statistically designed experiments, and a number of properties evaluated. A substantial saving in development time and quantity of drug was thereby achieved.The techniques of optimization in pharmaceutical dosage form design are well d o c~m e n t e d ' *~*~?~. Schwartz et al? developed a technique whereby a formulation with optimum properties could be obtained through computer assisted data analysis. They used the results of a statistically designed series of experiments, based on five independent variables, as input into a computer. Down et al.7 used a desk top computer for product optimization. Their method offered rapid access and 2089 Copyright 0 1993 by Marcel Dekker, Inc. Drug Dev Ind Pharm Downloaded from informahealthcare.com by University of Otago on 01/03/15 For personal use only.

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RF‐plasma polymerization and bonding of allylamine onto ultrahigh molecular weight polyethylene (UHMWPE) “Spectra™‐900” is described using an inductively coupled plasma reactor. This process was found to enhance the interfacial strength between the fibers (Spectra‐900) and room‐temperature‐cured epoxy matrix up to fivefold. Fibers covalently coated with allylamine plasma showed no loss in tensile strength, while argon gas plasma pretreatment of the same fibers caused up to 10% reduction in tensile strength depending on the energy and duration of the treatment. Optimum treatment was attained through a short argon plasma etching (15 s), followed by allylamine polymerization and coating for 3 min. The coating process was found to protect the fiber surface from etching by plasma ion bombardment. A loss of 19% of the original diameter was found during the 15 s precoating etching with argon plasma, indicating the sensitivity of the fiber structure to plasma etching.