药剂学英文版chpter 4.ppt

1 Concepts Powder a dry substance composed of finely divided particle a type of pharmaceutical preparation * * Chapter 4 Powders and granules Teaching goal Grasp of particle size and analysis, comminution of drugs, blending powders, medicated powders. Grasp of dry granulation and wet granulation. Powders (2)Granules which are prepared agglomerates of powdered Materials. Granules 2 Powders A Particle size and analysis 180um 80 250um 60 425um 40 850um 20 2.00mm 10 Sieve opening Sieve number B Powders of vegetable and animal drugs are offici- ally defined as follows: Very coarse (No.8) Coarse (No.20) Moderately coarse (No.40) Fine (No.60) Very fine (or a No.80) C Particle size can influence a variety of impo- rtant factors (1)Increase the rate of drug dissolution and its bioavailability. (2)Uniformly dispersed in liquid vehicle. (3) ensure dose-to-dose content uniformity. (4)Penetrability of particles intended to be inhaled for deposition deep in the respiratory tract. D A number of methods exist for the determination of particle size,including the following: Sieving Microscopy Sedimentation E Comminution of drugs (1)Grinding with a mortar and pestle(On a small). (2) various types of mills and pulverizers may be used to reduce particle size (On a large scale). Spherical pulverizer (a: low gear; b: feasible gear; c: high gear) Mechanical pulverizer F Blending powders spatulation trituration sifting tumbling Groovy blender V blender 3 Medicated powders A Aerosol powders B Bulk and divided powders 4 Granules Wet methods Granules are prepared by Effervescent granulated salts