PHRM 100 Lecture Notes - Lecture 8: Active Ingredient, Granular Convection, Elutriation
Document Summary
Active pharmaceutical ingredients + excipients are combined to produce a tablet. Flow characteristics and compactability are essential to tablet production. Mixing milling granulation tabletting. Powder mixing allows components to lie closer to each component. Random mixing ensures the dosage unit contains correct amount/ concentration of active ingredients and excipients. Powders are neutral so no spontaneous mixing or separation occurs. Rapid macroscopic mixing but no mixing within group of particles. Shearing: occurs when layer of material flows over another layer, breaking up lumps of material. Diffusion: moving powder bed dilates, decreasing the density: move particles can move through the void spaces by gravitational forces. Different mixers: tumbling mixers: free flowing powders and small shearing forces are not enough to break up aggregates, agitator mixers: mix large quantities of material and prone to dead spaces; difficult to clean. Preventing segregation: sieving: selection of particle size fractions so components of a similar particle size range, milling: reducing particle size, creating similar size distribution.
