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level: level 2

Questions and Answers List

level questions: level 2

Question	Answer
Reducing the particle size of the dispersed phase produces	slower rate of descent of particles
More solid particles = __ viscosity	more viscosity
the viscosity of a pharmaceutical preparation may be determined through the use of a viscometer such as this.	Brookfield Viscometer
1 Particle Size Reduction is accomplished by this prior to incorporation of the dispersed phase into the dispersion medium. 2 Particle Size- Diameter of suspension should be	1 Dry Milling 2) 1 to 50 µm
One of the most rapid, convenient and inexpensive methods of producing fine drug powders of about 10 to 50µm size	Micropulverization
Used in particle size reduction to finer particles, under 10µm. Usually employed for parenteral and ophthalmic suspensions.	Fluid Energy Grinding (Jet Milling/Micronizing)
Reduce particle size to that of extremely small dimensions	Spray Drying
One must AVOID reducing the particle size too much because it will form a __	compact cake upon settling to the bottom of the container
preferred shape of particles in a suspension	Barrel-shaped
preventing rigid cohesion of small particles of a suspension is formation of a less rigid or loose aggregation of particles	Floc or floccule
are commonly employed as the flocculating agent assists the suspension by helping to support the floc once formed	bentonite magma
flocculating agents reducing the electrical barrier between the particles of the suspensoid and forming a bridge so as to link them together	Electrolytes
induce flocculation of particles in suspension and increase the sedimentation volume.	Surfactants (Nonionic and ionic surface active agents)
particle settle too rapidly> hinders accurate dosage, produce an unsightly supernatant layer.	highly flocculated suspensions
are added to the dispersion medium to allow solute to be suspended in the medium	Suspending agents
They are used to thicken the dispersion medium Suspending agents	1 Carboxymethylcellulose (CMC), 2 Methylcellulose, 3 Microcrystalline Cellulose, 4 Polyvinylpyrrolidone, 5 Xanthan gum 5 Bentonite
can bind certain medicinal agents, rendering them unavailable or only slowly available for therapeutic function	Polymeric substances and hydrophilic colloids