Effect of compressional force on the crystallinity of directly compressible cellulose excipients

The effect of compressional force on the crystallinity of low crystallinity cellulose (LCPC), microcrystalline celluloses (Avicel(R) PH-101, PH-102 and PH-302 grades) and powdered cellulose (Solka Flee BW-100) has been investigated using an X-ray diffraction method. Microcrystalline and powdered celluloses showed an increase of about 10% in their crystallinities, compared to the values for the corresponding powders, at a compression pressure of 5-10 MPa. The increase in the crystallinity of LCPC was gradual and reached the maximum value of 5% at a compression pressure of 15 MPa. Further increase in compression pressure (to 77 MPa) had no effect on the crystallinity of LCPC, Avicel(R) PH-101, Avicel(R) PH-302 and Solka Floc BW-100. Avicel(R) PH-102, on the other hand, showed a decrease in crystallinity at 15 MPa. Beyond 15 MPa, however, no statistically significant change in the crystallinity of the product was noted. (C) 1999 Elsevier Science B.V. All rights reserved.