Powders Flashcards
dry finely divided drugs &/ or chemicals
POWDERS
intimate mixtures of drugs
POWDERS
intended for internal (oral powder) or external use (topical powder)
POWDERS
taken orally after mixing with water
Internal use of powders
taken orally after mixing with water
INTERNAL USE
medicated powders (e.g. analgesic powder)
INTERNAL USE:
dusted on the affected area from sifter-type container or applied from powder aerosol
EXTERNAL USE
should bear a label marked EXTERNAL USE ONLY
EXTERNAL USE
Advantages of Powder
- Faster rate of dissolution & absorption/rapid therapeutic
effect (large surface area) - More stable than liquid
- More convenient to swallow than tablet or capsules
- Ease in compounding (for eutectic mixture)
- Used in blending with medicated application as ointments,
suppositories and pastes - Can be made into granules for preparing tablets and or
reconstituted to liquid form
Disadvantages of Powder
1. Can’t mask undesirable taste
2. Inconvenient to carry
3. Difficulty of protecting from decomposition (hygroscopic,
deliquescent or aromatic materials)
4. Time and expenses required in the preparation of uniform
powders
5. Inaccuracy in dose
reducing the particle size of the powder to increase the solubility of the powder
Comminution/Particle size reduction
uses large mills & pulverizers
Large Scale
utilizes trituration, pulverization by intervention, levigation
Extemporaneous or Small scale
grinding a drug with the use of mortar & pestle
Trituration
Trituration on rough surface
Porcelain mortar
Trituration on smooth surface
Glass mortar
adding of volatile substance that aid in pulverization process (e.g. alcohol & camphor)
Pulverization with Intervention-
commonly used in small scale preparation of ointments to reduce the grittiness of added powders
Levigation
small amount of liquid in which the powder is insoluble (e.g. mineral oil, glycerin)
Levigating agent
is form by combining a powder and a levigating agent
paste
when 2 or more powdered substance are to be combined to form a uniform mixture it is best to reduce
the particle size of each powder
Blending/Mixing-
reducing the particle size of solid (comminution) before mixing with other components, further processing, or
incorporation into a final product
Mixing
Advantages of Mixing:
◼ Increase surface area which may increase the dissolution area and bioavailability
◼ Facilitates drying of wet masses
◼ Improves blending or mixing
◼ Permits uniform distribution of coloring agents
◼ Improves the function of lubricants
◼ Improve the texture, appearance and physical stability
Disadvantages of Mixing:
◼ Can change the polymorphic form of the active ingredient
◼ Degrade the drying
◼ Decrease bulk density
◼ Decrease the particle size which can cause particle aggregation
◼ Decrease dissolution rate
◼ Increase surface area, adsorption
uses large mixers
Large Scale Blending/Mixing
Enumerate some Extemporaneous/ Small Scale blending
Spatulation
Trituration
Sifting
Tumbling
Geometric Dilution
movement of spatula on a sheet of paper/ointment tile
Spatulation
not suitable for large quantities of powders or powders containing potent substances.
Spatulation
suited to mixing solid substances that form eutectic mixtures (or liquefy when in close and prolonged contact with one another).
Spatulation
examples that form eutectic mixtures when combined:
phenol camphor menthol,
thymol aspirin
phenyl salicylate
other similar chemicals
to comminute and to mix powders
Trituration
uses mortar & pestle
Trituration
Enumerate the Kinds of Mortar & Pestle:
- Glass- non-porous, smooth surface (suspensions, ointments)
- Wedgewood- crystalline solids
- Porcelain- soft aggregates/ crystalline
- Metal- not to be used in reactive substance
powders mixed by passing through the sifters - results in light, fluffy product.
Sifting
what is the result when powders mixed by passing through the sifters
Light, fluffy product
not acceptable for incorporation of potent drugs into a diluent powder.
Sifting
blending of powder in a rotating chamber (large vessel)
Tumbling
What is used in blending of powder in a rotating chamber
large vessel
use of a machine / motorized equipment (for industrial purposes).
Tumbling
mixing is thorough but time consuming
Tumbling
used when a small amount of potent substance is mixed with a large amount of diluent
Geometric Dilution
ensure the uniform distribution of the potent drug.
Geometric Dilution
combining by portions
Geometric Dilution
What are indicated in a geometric dilution when the potent and other ingredients are?
Same color
Visible sign of mixing is lacking
what ingredients are in convenient concentration using lactose as the diluents for
use at the Rx counter.
Strychnine sulfate, arsenic, mercury bichloride, atropine
What are the methods of determing the particle size?
Sieving
Microscopy
Sedimentation rate
Light energy diffraction/light scattering
Laser holography
Cascade implication
Particles passed by mechanical shaking through a series of sieves (from 40 to 9500 micrometers, depending upon
sieve sizes)
Sieving
are made of wire cloth woven from brass, bronze or other suitable wire; they are not coated nor plated
Sieves-
Particles are sized through the use of a calibrated grid back ground
Microscopy
Particle size is determined by measuring the terminal settling velocity of particles through a liquid medium in a
gravitational or centrifugal environment (range: 0.8-300 micrometers)
Sedimentation rate
Calculated using the Stoke’s Law.
Sedimentation rate
Determined by the reduction in light reaching the sensor as it passes through a sensor; utilizes a He-Ne laser, silicon
diode photo diode detectors and an ultrasonic probe
Light energy diffraction/light scattering
Pulsed laser is fired through an aerosolized particle spray and photographed in three dimensions with a holographic
camera, allowing the particles to be individually imaged and sized
Laser holography
Driven by an airstreams will hit a surface in its path, provided that its inertia is sufficient to overcome the drag force
that tends to keep in the airstreams.
Cascade impaction
Depending on their intended use, powders are packaged and dispensed by pharmacists as:
Bulk powders
Divided powders
powders dispersed in bulk form
BULK POWDERS
Medicated/Oral powders (antacid/ laxative powder)
BULK POWDERS
Douche powder (vagina)
BULK POWDERS
-Dissolve in warm water for vaginal use
Douche powder (vagina)
-Device use to introduce a stream water into the body for medical or hygienic reason usually for vaginal irrigation or any
body cavity
Douche powder (vagina)
non-medicated powder for external use: powders for ear, nose (Insufflations), throat, tooth sockets (dentrifices)
BULK POWDERS
divided portion of powder administered in controlled dosage
DIVIDED POWDERS
folded to enclose the medication
DIVIDED POWDERS
Latin for divided powders?
Chartulae or Chartula
Synonyms for divided powder?
Chart, powder paper, powder pockets
What is method used in Divided powder?
Block and Divide method
What preparation is divided powder
Preparation 1
description of Divided powder
dispensed in individual doses, usually in folded paper
Another type of dispensing for divided powders?
metal foil
small-heat sealed plastic bags
What are disadvantages of divided powder?
Unpleasant Tase
Rapid Deteriotation
What are the packaging materials used for divided powder?
Simple bond paper
Vegetable parchment
Glassine
Waxed paper
opaque paper with no moisture-resistant properties
Simple bond paper
thin semi-opaque paper with limited moisture-resistance
Vegetable parchment
glazed transparent with limited moisture-resistance
Glassine
transparent waterproof paper
Waxed paper
absorb moisture but does not liquefy
Hygroscopic
materials that liquefy
deliquescent
what is the solution for hygroscopic or deliquescent materials of powder?
powders are double wrapped in waxed paper
what is the solution for Limited barrier against moisture
Glassine & vegetable parchment papers
what is the solution for volatile components
wrapped in waxed or glassine papers and placed them in a heat-sealed plastic bag
what is the solution for neither volatile components nor ingredients adversely affected by air or moisture
wrapped in white bond paper
What are the Commercially available sizes (powder papers)- choose a convenient size to hold the powders
- 2.75 x 3.75 inches
- 3 x 4.5 inches
- 3.75 x 5 inches
- 4.5 x 6 inches
Divided powders can be prepared by:
Individual weighing
Block and divide method
weigh separately before enfolding in a paper using a digital analytical balance
Individual weighing
prepared powder were placed on a flat surface (porcelain, glass plate or pill tile)
Block & divide method
using a spatula, form a rectangular or square block of powder having a uniform depth
Block & divide method
-using a spatula, the divided portions were cut lengthwise & crosswise
Block & divide method
-each smaller blocks is separated, transferred to the paper & wrapped
Block & divide method