WEEK 5 (CHAPTER 6) Flashcards
- Defined as a dosage form composed of solid or mixture of solids reduced to a finely divided state and intended for internal or external use.
- enable a primary care provider to alter the quantity of each medication for each
dose. (Used in clinical studies of drug preparation) - For infants and young children. You can mix with formula or sprinkle with applesauce
- provide a rapid onset of action
Medicated powders is limited but the use of powdered substances in the formation of other dosage form is extensive
Powder
agglomerates of powdered materials
Granules
Physicochemical considerations:
- Particle size
- Particle shape
- Particle density
- Electrostatic charges
- Adhering/repelling properties
dimension of solid
Particles of uniform size are blended easier
Particle size
Spherical particles are easier to mix and transported easily from an area of high conc to low conc
Needle-shaped and cubic-shaped particles do not slide over each other as easily and tend to clog or stick together
Particle shape
- heavy particles sink while light particles tend to rise
Particle density
- Static electricity hamper blending
- Overcome by humidification of the work area.
- Add sodium lauryl sulfate to neutralize the charges.
Electrostatic charges
-Some particles tend to adhere or repel each other
- The faster they are individually diluted with an inert substance or nonreactive material in the formulation, the easier it is to blend them
Adhering/repelling properties
-all particles pass through sieve no. 8 and not more than 20% pass through sieve number 60.
Very coarse (No. 8)
- All particles pass through sieve no. 20, and not more than 40% pass through sieve no. 60
Coarse (No. 20)
- All particles pass through sieve no. 40 and not more than 40% pass through sieve no. 80
Moderately coarse (No. 40)
All particles pass through sieve no. 60 and not more than 40% pass through sieve no. 100
Fine (No. 60)
Particles are passed through mechanical shaking through a series of sieves of known and successively
smaller size
Sieving
All particles pass through sieve no. 80. There is no limit to greater fineness
Very fine (No. 80)
Sample particles are sized through the use of calibrated grid background
Microscopy
Determined by measuring the terminal setting velocity of particles through a liquid medium in a gravitational or centrifugal environment.
Sedimentation rate
Methods to Determine Particle Size
determined by reduction in light intensity reaching the sensor as the particle
dispersed in a liquid or gas, passes through the sensing zone
Utilized He-Ne laser, silicon photo diode detectors, ultrasonic probe
Light energy diffraction/Light scattering
Methods to Determine Particle Size
pulsed laser is fired through an aerosolized particle spray and is photographed in three dimensions with a holographic camera
Laser holography
Methods to Determine Particle Size
Principle: a particle driven by an airstream will hit a surface in its path, provided its
inertia is sufficient to overcome the drag force that tends to keep it in the airstream.
Particles are separated into various size ranges by successively increasing the velocity of the airstream in which they are carried.
Cascade Impaction
- grinding a drug in a mortar to reduce its particle size
- Employed to comminute and mix powders If simple admixture without need for comminution-use glass mortar
Trituration or comminution
-for uniform distribution when you mix a small amount of potent substance in a large amount of diluent. It is preferred
if both substance are the same color and a visible sign of mixing is
lacking.
Geometric dilution
- Tumbling the powders in a rotating chamber designed to enhance the mixing
process - Time consuming
- Speed to rotating chamber is such that powders tumble over and over and do not simply slide down the slide of the chamber
- Widely used in industry on a large scale
V blender
Consist of three individual chambers attached to the blender power unit and allows up to three different blending processes to be conducted simultaneously
Triple V blender
- The blender is used to obtain homogenous mixing of powders with
different specific weights and particle size - The mixing container is subjected to three-dimensional movement that
exposes the product to continuously changing, rhythmically pulsing
motion
Turbula mixer
Can result from gravity causing small particles to move into voids between larger particles because of large particle size differences
Percolation
Causes small particles to move under large particles that are pushed to the surface
and result in separation of differently sized particles
Vibration
- Some powders become pasty or sticky or they may liquefy when mixed together
- To keep powders dry, mix with a bulky powder adsorbent like light
magnesium oxide or magnesium carbonate - Triturated very lightly on a pill tile by using a spatula rather than a
mortar and pestle
Eutetics
will absorb moisture from air
Hygroscopic powders
will absorb moisture from air and then partially or wholly liquefy
Deliquescent powder
- A crystalline powder that contains water of hydration or crystallization
- This water can be liberated during manipulation or on exposure to low
humidity environment - Powders may become sticky and pasty or liquefy
- Use anhydrous salt form of the drug
Efflorescent powder
- Uniform, small particle size with an elegant appearance
- More stable than liquid dosage forms and are rapidly soluble enabling the drug to be absorbed quickly
- The properties of powder relates to its size and surface area of particles so if powders have a large surface area they are exposed to atmospheric conditions so better dispensed them in tight containers
Composition
- Free flowing and impalpable (pass them through sieve 100)
- Uniform small particle size that won’t irritate the skin when applied
- Prepared that it adheres to the skin
- Highly sorptive powders should not be used for topical powders that are to be applied on oozing wounds as a hard crust may form.
- More hydrophobic water repellant powder will prevent loss of water from the skin and will not cake on oozing surfaces
Topical Powders
- Finely divided powders that are intended to be applied in a body cavity such as
ears, nose, vagina, tooth socket or throat - Use an insufflator or puffer and patient simply puffs the desired quantity on a
cavity
Insufflated powders
Administered by inhalation with the aid of
dry powder inhalers which deliver micronized particles in metered quantities
Aerosol powders
- Advair diskus
- Fluticasone propionate inhalation powder
- The Foradil Aerolizer
Oral Inhalation Powders
- are defined as a dosage form composed of dry aggregates of powder particles that may contain one or more APIs, with or without other ingredients.
- They may be swallowed as such, dispersed in food, or dissolved in water.
- are frequently compacted into tablets or filled into capsules, with or without additional ingredients.
- are prepared agglomerates of smaller particles of powder.
- They are irregularly shaped but may be prepared to be spherical.
Granules
are granules or coarse to very coarse powders containing a medicinal agent in
a dry mixture usually composed of sodium bicarbonate, citric acid, and tartaric acid.
Effervescent salts
