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Fine powders that can result from any dry substances
As dosage forms _____ are thorough mixtures of dry, finely divided drugs and _____ that are intended for internal or external use
What is the usual powder size ranges of powder?
Why is particle size important?
Topical use: powders affect the degree of comfort and irritation to the skin
Internal use: Powders have an effect on dissolution, bioavailability, rate of settling (in suspension), and can avoid stratification on standing or when transported
What does the USP use to distinguish particle size?
Particle size is based on screen size and the sieve used.
What mesh size and opening size would you use on very course granules?
mesh opening size: >1000
mesh size: 2-10
What mesh size and opening size would you use on course granules?
mesh opening size: 355-1000
mesh size: 20-40
What mesh size and opening size would you use on moderately course granules?
mesh opening size: 180-355
mesh size: 40-80
What mesh size and opening size would you use on fine granules?
mesh opening size: 125-180
mesh size: 80-120
What mesh size and opening size would you use on very fine granules?
mesh opening size: 90-125
mesh size: 120-200
To reduce to powder; pulverize
Type of comminution:
_____is the continuous rubbing or grinding of the powder in mortar with a pestle. This method is used when working with hard, fractural powders.
Types of comminution:
_____ is used with crystalline powders that do not crush or triturate easily; or gummy-type substances. Intervention is done by dissolving the compound in solvent (e.g. alcohol, acetone)
Pulverization by intervention
Types of comminution:
_____ reduces the particle size by triturating in a mortar or spatulating it with small amounts of viscous solvent (mineral oil or glycerin), in which the solid is not soluble. Used in compounding and suspensions.
What are three different methods of "blending"?
- 1. spatulation
- 2. tumbling
- 3. geometric dilution
Which method of blending will reduce the melting process?
A substance is referred to as a _____ if it lowers the surface tension of a liquid, thus allowing it to spread more easily.
wetting agent (ex. Bismuth nitrate)
What are the advantages of using powders?
each dose can contain a different amount of active drug
can be administered easily to infants and young children who cannot swallow tablets or capsules
rapid onset of action of the drug since disintegration is not required
can be made into different dosage formulations
List for powder types used based on physiochemical considerations.
- 1. Eutectics
- 2. Hygroscopic and Deliquescent Powders
- 3. Efflorescent Powders
- 4. Effervescent Salts
Powders that become sticky or pasty, or liquify when mixed together
How would you resolve a eutectic mixture from liquifying or becoming sticky?
mix with bulky powder absorbents
use light blending with a spatula instead of a mortar & pestle
make eutectics and then absorb it on to a bulky powder
What property describes the absorbing of moisture from the air (dampening effect)
What property describes the absorbing of moisture from the air to the extent that a powder will partially of wholly liquify?
What are some remedies against hygroscopic and deliquescent properties in powders?
use a desiccant packet or capsule
store in a dry place in tight containers
dilute the powder with drying agents
A crystalline powder that contains water of hydration or crystallization
Water is liberated either during manipulation or upon exposure to a high humidity environment
How do you remedy the effects of efflorescent powder?
use anhydrous salt form of the drug
use drying bulky powder and light, non-compacting mixing method
Are usually mixtures of effloresced citric acid and/or tartaric acid combined with sodium diphosphate and/or sodium carbonate
What is the disadvantage of using effervescent salts?
large exposed surface area, which provides greater reactivity for effervescence, which leads to potential stability problems (overcome by use of granules)
What are the pharmaceutical uses of powders?
can be applied to skin for local effect
can be offered for internal use as a convenient method of dispensing non-potent, powdered drug that does not require precise and accurate dosing
can be used as divided powders or "chartulae"
can be encapsulated in to hard shelled capsules or compressed in to tablets