The influence of particle size and shape of components of binary powder mixtures on the maximum volume reduction due to packing

• Published in: International journal of pharmaceutics Vol. 137; no. 1; pp. 41 - 47
• Main Authors: Podczeck, Fridrun, Sharma, Monica
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 21.06.1996; Elsevier
• Subjects: Binary powder mixtures; Biological and medical sciences; General pharmacology; Kawakita-equation; Medical sciences; Miscellaneous; Particle shape; Particle size; Pharmacology. Drug treatments; Powder packing; Particle size; Particle shape; Powder packing; Kawakita-equation; Binary powder mixtures; Binary mixture; Reduction; Volume; Powder
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/0378-5173(95)04420-5

The influence of particle size and shape of components of binary powder mixtures on the maximum volume reduction due to packing has been investigated in a systematic manner using the Kawakita-equation. Different grades of microcrystalline cellulose were mixed with defined size fractions of angular particles (lactose monohydrate), spherical particles (Elcema G250) and needle-shaped particles (acetylsalicylic acid). The particle shape of the mixture components clearly influenced the maximum volume reduction due to packing, represented by the Kawakita constant a. While angular particles improved the packing properties of the microcrystalline celluloses, the addition of spherical and needle-shaped particles generally resulted in lower values for a at equivalent concentrations. The addition of both spherical or needle-shaped particles in concentrations between 25% and 75% to fine grade microcrystalline cellulose led to a steady decrease in volume reduction ability, whereas for medium or coarse grade microcrystalline cellulose the graphical presentation of a as a function of concentration of the second mixture component always showed a maximum value. The particle size of both powders contained in the binary mixtures influenced the values of the Kawakita constant a with the exception of angular particles. The finer the particle size of each component, the larger became the value of a.