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
