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an intimate mixture of dry, finely divided drugs or chemicals
powder
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prepared agglomerates of powdered materials
granules
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advantages of powders
- versatile and convenient
- doc has options to deviated from the conventional dose
- stable
- can be reduced to desired size for rapid absorption
- less incompatibility
- small particles offer large surface area
- can be mix with milk, juice to become palatable
- economic wise
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disadvantages of powders
- may be misunderstood in correct method of use
- undesirable to take bitter or unpleasant tasting drugs by oral admin
- difficult to protect from hygroscopic, deliquescent or aromatic materials from decomposition
- individually wrapped dose or sachet are required and it increases expense
- must be homogeneous blend of all the components
- must be the most advantageous particle size
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types of powders
- bulk powder
- divided powder
- dry powder
- dusting powder
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composed of a large # of very fine particles that may flow freely when shaken or titled, in what bottles
- bulk powders
- glass or plastic bottles
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individual powders packed separately that is volatile, hygroscopic or deliquent; what bottles
- divided powders
- foil or plastic bottles
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powdered agent made up of a base and an active ingredients
dusting powders
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device that delivers medicated to the lungs in the form of dry powders
dry powder inhaler
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other name of dry powder inhaler
insufflator or nasal powders
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sizes of sieves according to USP
- very coarse no. 8
- coarse no. 20
- moderately coarse no. 40
- fine no. 60
- ver fine no. 80
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particle size and analysis method:
- sieving
- microscopy
- sedimentation rate
- light energy diffraction / light scattering
- laser holography
- cascade impaction
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simplest and the most commonly used method used for determining particle size distribution; by mechanical shaking
sieving
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measured using calibrated grid background
microscopy
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terminal settling velocity of particles through a liquid medium in a gravitational and centrifugal environment and calculated by Stroke's Law
sedimentation rate
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determined by the reduction of light reaching the sensor
light energy diffraction
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pulsed laser is fired through an aerosolized particle spray and is photographed in 3D with a holographic camera
laser holography
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particle size driven by an air stream will hit a surface in its path
cascade impaction
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methods in small scale comminution
- grinding or truituration
- levigation
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method used for ointments or suspension
levigation
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methods in large scale comminution
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two or more powdered substances are to be combined to form a uniform mixture
blending powders
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employed both to comminute and to mix powders
trituration
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small amount of potent substances is to be mixed by large amount of diluent
geometric dilution
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mixing of 2 or more powders by passing it in sifter
sifting
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blending the powders in a rotating chamber
tumbling
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