【正文】 b)artificial respiratory system 4. contents(凈含量 ): WtotalWcontainer 5. foam stability: visual evaluation, rotational viseter, rod falling, mass peration 49 Testing of pharmaceutical aerosols (continued) 6. particle size determination: cascade impactor(級聯(lián)撞擊器 ):~30 microns light scatter decay: Tyndall beam 7. leakage D. biologic characteristics 1. therapeutic effect 2. toxicity 50 Packaging of powders ? Bulk powders limited to nonpotent substances such as a) antacid powders and laxative powders b) douche powders c) medicated powders for external application antiinfectives or antifungals d) powder containing nutritional supplements ? Divided powders a) weigh each portion separately for potent drug b) blockanddivide method for nonpotent drug approximate each portion 51 granules Preparation of granules 1. wet methods 1) basic wet method a) moistening the powder mixture (pastelike mass) b) granulation by screening (wet granules) c) drying (dry granules) d) sizing the granules by screening (finished granules) 2) fluidbed processing Particles are vigorously dispersed and suspended while a liquid excipient is sprayed on them and the fluidized product dried, forming granules or pellets of defined particle size. 52 granules Preparation of granules 1. dry methods 1) pactor/granulation a) Roll pactor (densified sheets or forms) b) Granulating machine 2) Slugging method a) Compression of powder mixture into large tablets b) Granulated into desired particle size Disadvantage of dry methods: the production of fines 53 The advantages of granules ? Flow well pared to powders ? Stable to the effects of atmospheric humidity and less likely to cake or harden upon standing ? Easily wetted by liquid ? The antibiotics that are unstable in aqueous solution are prepared as small granules for constitution prior to dispensing 54 Effervescent granulated salts Features: ? Dosage form: granules or coarse to very coarse powders to decrease the rate of acidbase reaction ? Composed of sodium bicarbonate, citric acid, and tartaric acid ? The acids and base react to liberate carbon dioxide upon contacting water which masks undesirable taste and facilitates disintegration. 55 Effervescent granulated salts The choosing of acids ? Tartaric acid alone: the resulting granules lose their firmness readily and crumble ? Citric acid alone: a sticky mixture difficult to granulate ? The bination of citric and tartaric acids is preferrabe. The preparation method: fusion method, wet method 56 The preparation of effervescent granules—— fusion/dry method The one molecule of crystallization water present in each molecule of citric acid acts as the binding agent for the powder mixture. Mixing of powders: rapidly。 high production speeds。 motorized powder blenders (largescale) →widely employed in industry Mixing is thorough, although timeconsuming The methods of blending —— 5. stirring (攪拌 ) also frequently used on large scale. 29 Medicated powders Application ? internally (with blue label) a. taken orally after mixing with water b. inhaled into the lungs c. packaged with a liquid solvent or vehicle for constitution (orally, as an injection, as a vaginal douche: A stream of water, often containing medicinal or cleansing agents, that is applied to a body part or cavity for hygienic or therapeutic purposes.) eg. antibiotics for pediatric use ? externally (with red label, externally use only or topical) a. siftertype(篩罐 ) container b. a powder aerosol 30 Medicated powders the advantage and disadvantage of medicated powder ? advantages a. suitable for patients who have difficulty swallowing solid dosage forms b. faster rates of dissolution and absorption than solid dosage forms (oral powders for systemic use) ? disadvantage a. the undesirable taste of the drug 31 Aerosolized powders Various application form ? Pressurized aerosols To make the powder deposit deep into the lungs, the particle size of the micronized medication is prepared in the range of 1 μm to 6 μm in diameter. ? Mechanical devices (SPINHALER) for the delivery of powders in a capsules ? Powder blowers or insufflators 32 The definition of aerosols(氣霧劑 ) Definition An aerosol is defined as a system that depend on the power of a pressed or liquefied gas to expel the contents from the container with spec