POW.GRAN-notes-2010

POW.GRAN-notes-2010 - University of Wyoming PHCY 6100 Solid...

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Unformatted text preview: University of Wyoming PHCY 6100 Solid dosage forms For oral use: powders, granules, capsules, tablets, lozenges, controlledrelease forms. b) For non-oral use: pellets or inserts, vaginal tablets, powders for topical use or inhalation. c) Preferred form to prepare any drug: higher stability d) Powders and granules may be used i. “per se” ii. for the preparation of other dosage forms a) POWDERS Def. Fine particles that can result from the comminution of any dry substance (physical form of a substance). 1. a) As dosage form powders are thorough mixtures of dry, finely divided drugs combined with excipients. b) Are intended for internal (oral) or external (topical) use. Powders, Granules & Particle size: defined by USP (proportion of particles passing through standardized sieves or mesh fraction terminology = Very coarse, Coarse, Moderately coarse, Fine, Very fine). 2. Some examples of sieve numbers, openings, and descriptive terms related to sieves Sieve No. Sieve opening mm 2 9.52 4 0.84 30 0.59 40 0.42 50 0.297 60 0.250 70 0.210 80 0.177 200 0.074 400 0.037 (USP) 2.00 20 General Applications Standard 4.76 10 Descriptive Teixeira Very coarse Used to sift granulated effervescent salts and granulations for compressed tablets (sieves # 2-40) Coarse Moderately coarse Fine Used to sift powdered effervescent salts and divided powders (sieves # 50-120) Very fine Used to sift divided powders for dusting, adsorbents, inhalants, and others (sieves # 200-400) 1 University of Wyoming PHCY 6100 Particle size can influence: a) i. Dissolution rate: in solutions ii. Suspendability: uniform dispersion of suspensoid. iii. Uniform distribution: powder mixtures or solid dosage forms. iv. Penetrability: topical and inhalation v. Lack of grittiness: dermal and ophthalmic MICROMERITICS: the study of particle size, is based on: b) i. Majority of dosage forms are solids. ii. Physical state of particles (size, shape, number) may be changed by physical manipulation during preparation of dosage forms. iii. Particle’s characteristics may affect therapeutic effectiveness. Particle size reduction c) Small scale: comminution i. • • ii. 3. Trituration (mortar and pestle; glass for potent materials and dyestuffs, and porcelain for most other purposes) Levigation (mineral oil, glycerin) Large scale: mills with blades, grinders, pulverizers. Preparation of Powders a) Geometric dilution: always used if small amount of potent drug is mixed with other powders. b) Spatulation: if small amounts are prepared. c) Trituration: mixing and reduction of particle size in one step (periodic “fluffing”). d) Sifting: not for potent drugs; a fluffy product is produced. e) Tumbling: in rotating chamber; mechanical mixers and blenders. f) Zip bag: compounding 4. Packaging of powders a) Bulk: sifter-type canister, powder shakers, aerosol (inhalers _ Alupent®), spray, wide-mouthed glass, plastic or metal jar or bottle, plastic puffer units (insufflations). b) Divided: individual pre-measured dose units i. charts (compounded) ii. packets or sachets (industrial packaging) Teixeira 2 University of Wyoming 5. PHCY 6100 Applications/Advantages a) Dose can be readily adjusted (oral) b) Easy to administer to pediatric or geriatric patients (mixed with foods or liquids) c) If a drug is too bulky to be prepared as a capsule or tablet d) Provide rapid onset of action (readily dispersed, large surface area, no disintegration prior to absorption) GRANULES 1. Def: agglomerates of smaller particles of powder, 4 to 12 mesh size range (v. coarse powder). 2. Preparation Wet method a) i. Blended powder mix + binder agent (moistened) + sieve of desired mesh size + dry at air or oven ii. Binder agents: work as wetting agent for powders and have adhesive properties (Ex: acacia, gelatin, cellulose derivatives, pre-gelatinized starch). Dry methods: b) i. ii. 3. Granulating machine or granulator Slugging Characteristics of granules Flow freely and uniformly: ideal in preparation of tablets More stable chemically and physically than powders: less surface area Less likely to harden or cake upon standing More stable to effects of atmosphere (less surface area) More easily wetted by solvents (powders may float) Granules for constitution: some antibiotics a) b) c) d) e) f) EFFERVESCENT POWDERS OR GRANULES 1. Preparation: Granules or coarse powders + Effervescent mixture 2. Effervescent mixture: dry mixtures of citric and tartaric acid with sodium biphosphate, carbonate or bicarbonate. Teixeira 3 University of Wyoming PHCY 6100 3. Effervescent powders or granules produce carbon dioxide (effervesce) when placed in water or aqueous liquid. 4. Effervescent powders/granules are especially suitable for products with a bitter or salty taste (resulting solutions will be carbonated and taste of drug will be masked easily). 5. Advantage of effervescent granules over effervescent powders • It is easier to control the rate of effervescence of granules when the product is added to water: granules expose less surface area, hydrate and dissolve slower = more controlled effervescence. Teixeira 4 ...
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