A Guide to Pharmaceutical Particulate Science

Physical Characterization of Component Particles Included in Dry Powder Inhalers. II. Dynamic Characteristics

“…Flow properties are also influenced by surface roughness and particle morphology. 8 Irregularly-shaped and rough particles have more contact points than spherical and smooth particles, and hence, have decreased powder fluidity 9,10 due to an increase in cohesive forces, frictional forces (described above), and a greater tendency for mechanical interlocking 6 (described above). Spherical particles have optimal flow properties, since they possess minimal interparticulate contact.…”

Spray‐dried carrier‐free dry powder tobramycin formulations with improved dispersion properties

“…Temperature and humidity cycling, or poor drying may result in solid bridging through crystallisation phenomena at the particle surface. 23 The forces of interaction between pharmaceutical powders are difficult to characterise and control because of heterogeneity in particle composition and physicochemical characteristics. Consequently, it is difficult to consider each of the forces independently.…”

Physical Characterization of Component Particles Included in Dry Powder Inhalers. I. Strategy Review and Static Characteristics

“…Briefly, it is important to consider crystalline solids, [33][34][35][36] crystalline polymorphs, 37,38 crystal hydrates, 39 amorphous, [40][41][42][43] liquid crystals, 44 nanocrystals, and solid-state phase transitions. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Indeed, the subject of a local polymorphism with single crystals is extremely topical and the subject of some very recent debate. [45][46][47][48] Solid-state phase transitions include polymorphic interconversions, polyhydrate interconversions, hydration-dehydration conversion, and order-to-disorder transformations.…”

“…Interest in particles may be viewed as one of the oldest scientific activities since the degree of subdivision, or size, is all that separates nanoparticles from boulders. 1 Pharmaceutical powders are, in the first instance, of greatest importance for oral dosage forms where particle behavior is crucial to the processes involved in tablet and capsule manufacture and ultimately in their dissolution and drug availability. This interest extends to aerosol products that are highly dependent on the physico-chemical and performance characteristics of the particles that deliver drugs to the lungs.…”