PHAR2823 Lecture 6: Solid-Dosage-Forms6
Document Summary
Reduce bulk volume by eliminating voids and bring particles into closer contact. Compressibility ability of powder to reduce in volume under pressure (as a results of displacement of gaseous phase: consolidation. Increase mechanical strength due to inter particulate interactions. Basic concepts: elastic deformation, plastic deformation and brittle fracture. Plastic deformation and/or brittle fracture occur when elastic limit is reached. Initially, powder flows into the die cavity and attain immediately a loose packing. As the upper punch is lowered down the powder attains close packing. Size: small particles enter voids between large particles. Porosity: greater porosity of powder bed, greater particle rearrangement. Shape: spherical particles tend to assume closer packing arrangements than irregular particles. As the punch is lowered further, the particles deform elastically. Once the elastic limit is reached, plastic deformation and/or brittle fracture occur, creating new surfaces for bonding to form the tablet.
