The influence of initial packing on the compression of powders

Abstract

The influence of the initial packing density on the compression properties of lactose and sodium chloride has been studied. Differences in initial packing density are eliminated for both materials at relatively low pressures. The results have been analysed by the equations of Kawakita (1956), Heckel (1961), and Cooper & Eaton (1962). The constants derived from the Cooper & Eaton equation are dependent on the choice of low pressure data. The Kawakita constants are influenced by the initial packing of the powder. The Heckel treatment uses data at pressures above the point where the initial packing exerts an influence. Hence the constants are independent of the initial packing. If comparisons are to be made between processing treatments or mixtures which change the initial packing of the powder, the Heckel equation would appear to offer the most valid approach.

A SNP assay for assessing diversity in immune genes in the honey bee (Apis mellifera L.)

“…A list of 209 immune genes putatively involved in honey bee defence against viruses 14 , 17 , 54 , 55 and Nosema spp. infections 30 , 33 , 38 , 45 , 56 was compiled from the literature (Supplementary Table S1 ).…”

The Parametrical Investigation of the Dilution Potentials of Some Direct Compression Agents : Bazi Doğrudan Basim Ajanlarinin Di̇lüsyon Potansi̇yelleri̇ni̇n Parametri̇k Olarak İncelenmesi̇

“…For this purpose, flat-face punch of 12 mm diameter and hydraulic press were used. Equal volumes of powders (1357.17 mm 3 ) were compressed at 767.0, 1150.5, 1535.0, 1917.0, 2301.5 and 3068.1 kgf/cm 2 (5)(6)(7)(8)(9). Reaching the desired pressure it was kept at the required value for 30 sec (10).…”

“…is: The Kawakita eq. is: In the Kawakita eq., "a" is a numeric parameter indicating the initial porosity of the compressed powder mass and "b" is the compression coefficient (7). At the dilutions that were prepared with Elcema G 250, the reason why the initial and the highest dilution values' consolidation differences were too similar to each other was that the particle size of Elcema G 250 and Lactose EP D-30 was not close to each other.…”

Modulated Uniaxial Compression Analysis of Respirable Pharmaceutical Powders

“…In general, CBD measurements are based on uniaxially compressing a powder sample and measuring its density under a defined pressure. A number of studies involving low-pressure compression of pharmaceutical powders have been reported (Faulhammer et al, 2014;Heda et al, 1999;Kostelnik et al, 1968;Llusa et al, 2014;Nikolakakis et al, 1998;Podczeck and Lee-Amies, 1996;Sheikh-Salem and Fell, 1981;Sørensen et al, 2005Sørensen et al, , 2006. A previous report has also used a commercial compression instrument that can accommodate milligram powder quantities for bulk density measurements (Sørensen et al, 2005).…”