15 Questions
What is the purpose of controlled flocculation in pharmaceutical dosage forms?
To prevent the formation of compact sediment
How is controlled flocculation usually achieved?
Combination of particle size control, use of electrolytes, and addition of polymers
What is the role of electrolytes in converting a suspension from a deflocculated to a partially flocculated state?
Alter the zeta potential and reduce the electric barrier between particles
What do polymers termed as 'polyelectrolytes' do in controlled flocculation?
Become ionized in an aqueous solution and act both electrostatically and sterically
How do electrolytes act as flocculating agents?
By reducing the electric barrier between particles and decreasing the zeta potential
What are the most widely used electrolytes for flocculation?
Sodium salts of acetates, phosphates, and citrates
What effect does a decrease in zeta potential have on suspended particles?
It leads to a decrease in repulsion force and the formation of a bridge between adjacent particles
Which type of surfactants can cause flocculation by neutralizing the charge?
Anionic surfactants
How do optimum concentrations of surfactants reduce the surface tension between liquid medium and solid particles?
By reducing the surface tension
What effect do non-ionic surfactants have on the charge density of a particle?
They have a negligible effect on the charge density
How do polymeric flocculating agents promote flocculation?
By forming bridges between projected parts of the polymer chains
What is the purpose of structured entrapping vehicles in relation to flocculated particles?
To increase physical stability of suspension by retarding sedimentation rate
Which type of polymers are examples of structured entrapping vehicles?
Non-Newtonian polymers with thixotropic behavior
1
What type of methods can be applied after adding wetting agent and dispersion medium to particles?
What are structured vehicles used to increase in suspensions?
Viscosity
Test your knowledge of pharmaceutical dosage forms with a focus on controlled flocculation and its mechanisms. This quiz covers the prevention of compact sediment formation and the use of polymers and electrolytes in achieving controlled flocculation.
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