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34 Cards in this Set

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What are powders?
mixtures of dry, finely divided drugs intended for internal or external use.
What are the advantages and disadvantages of powders?
A) faster dissolution and absorption, easier to swallow, improved dry stability

D) undesirable taste, poor flow
How have powders been historically used?
orally, through nose as snuffs, insufflation, externally to compromised area.
How are particle sizes differentiated?
Very coarse, Coarse, Moderately Coarse, Fine, or Very Fine
How are particles characterized?
by morphology, purity, stability, and size
6 methods to determine particle size?
Sieving, Microscopy, Sedimentation, light scattering, laser holography, and cascade impactor
What is a cascade impactor?
multi-stage impaction device for separating airborne particles by size.
How can particle sizes be reduced?
MANUALLY by trituration or levigation, good for small pharmacy

Mechanically by blade grinders which are good for industry
Describe methods of small scale blending
1)spatulation - using spatula, not good for large quantities or potent drugs

2) trituration - mortar and pestle, good for community pharmacy

3) levigation - mortar and pestle, a paste is formed by combining powder and liquid
Describe methods of large scale blending
1) Sifting - results in light, fluffy product

2) Tumbling - rotating chamber, thorough mixing

3) Twin Shell Blender - rolling rather than sliding, simple cleaning

4) Vertical Impeller - little floor space, screw-type impeller

5) Fluidized Mixer - air stream enters bottom and powder is fluidized
When are oral powders useful?
1) local (laxative, antacid) or systemic (analgesic) effects

2) patients with difficulty swallowing

3) for large dose meds too bulky for tablets

4) easily mixed with food/beverage
Describe topical powders
contain micronized particles mostly used for anti fungal or antibacterial. stored in a sifter-type container
Describe insufflated powders
used to deliver drug to ear, nose, throat, tooth socket or skin but with difficulty in proper dose delivery
Describe aerosol powders
uses a dry-powder metered inhaler with particles 1-6 micrometers
Describe problems with Eutectic powders. How is this overcome?
- some powders may become sticky, pasty, or may even liquefy when mixed
-to overcome, mix powders with a bulky powder absorbent (Magnesium Carbonate) and triturate very lightly with a spatula
What are Hygroscopic and Deliquescent powders? How are the problems with these overcome?
Hygroscopic - absorb moisture
Deliquescent - absorb moisture from air and liquefy

To overcome, disperse in tight containers with dessicant, and instruct to store in a dry place.
What are bulk powders?
powders dispersed in bulk and measured out doses by the patient, limited to non-potent meds
Examples of Bulk Powders
1)antacids (sodium bicarbonate)
2)Laxatives (metamucil)
3)Douche powders (mussengill)
4)Topical anti-infectives (bacitracin zinc)
What are divided powders?
commonly used for potent drugs, blended by geometric dilution and over dose is divided into individual dosing units
Describe the process of preparing charts for divided powders
For potent drugs: weigh each powder quantity

For non-potent drugs: block and divide method
Describe the process of dispensing charts for divided powders
1)place weighed powder into small zipper bag
2)place self-contained powder papers into zipper bag
3)place powders into powder papers, which are folded and boxed
Describe packaging of bulk, divided, topical, and insufflation powders
Bulk - in glass, plastic or metal with wide mouth

Divided - individually folded

Topical - poured into sifter-top containers or powder shakers

Insufflations - filled into plastic units
Describe the 4 types of paper used for divided powders
Bond - for powders not affected by air or moisture

Vegetable - limited barrier against moisture

Glassine or Glazed - limited barrier against moisture

Waxed - waterproof, may be double wrapped
Describe how quality is controlled with bulk and divided powders
Bulk - compare final weight with theoretical weights to examine for uniformity and freedom from caking

Divided - individually weigh packets and compare to theoretical weight, each checked for uniformity
How should be powders be stored?
dry places and may require protection from light
What are granules?
agglomerates of smaller powder particles. irregularly shaped, but may be spherically prepared
Describe the 2 dry methods of preparing granules
DM1: pass dry powder through set of rollers running in opposite directions, dense sheets collected and then passed through granulating machine

DM2: slugging used to prepare large tablets or slugs
Describe the 2 wet methods of preparing granules
WM1: moisten powder then pass through screen, collect in drying tray and dry by air or heat

WM2: fluid bed processing, disperse and suspend particles, spray liquid excipient to add consistency and dry to form granules
What are advantages of granules over powders?
flow better, less surface area, and are "wetted" by liquids easier
What are effervescent granulated salts?
-granules or coarse/very coarse powders
-contain medicinal agent in dry mix of sodium bicarbonate, citric acid and tartaric acid
-when added to water, the acids and bases react to liberate CO2, resulting in effervescence
What are advantages of effervescent salts over powder?
-masking of bad taste
-granules reduce rate of dissolution and prevent uncontrollable effervescence
Why use citric and tartaric acid together when forming effervescent salts?
Because Citric Acid alone produces sticky mixture which is hard to granulate and Tartaric acid alone produces granules that lose firmness and crumble
Describe the fusion method of preparing effervescent salts
1)Citric Acid crystals powdered
2)Mix with other powders
3)mix rapidly in low humidity
4)place in dish and heat to 34-40 celsius
5)citric acid releases water of crystallization, dissolving powder mixture
6)remove from oven, run through sieve to produce granules
7)dry and seal in tight containers
Describe the wet method of preparing effervescent salts
-uses water added to alcohol as binding agent.
- water is added to powder to prepare a mass and then granulated as in fusion method