session 32 practice

Disperse system is a liquid preparation in which drug is referred to as the _______ phase, or _______ phase that is ________ and the vehicle is termed the ______ phase, or ______ phase that is __________

dispersed; internal; discontinuous; dispersing; external; continuous

Colloidal dispersion has particle size in a range of:

 

20-50 um

 

<0.5 um

 

10-50 um

 

1-10 um

<0.5 um

According to Stokes equation, the sedimentation rate of particles increases with _______ (increase, decrease) particle size and/or ________ (increase, decrease) viscosity of the medium

increase; decrease

The effective way to improve physical stability of suspension is to change _______ phase

dispersed

Which of the following will help prevent cake formation in a parenteral suspension?

 

Add preservatives

 

Use a clay

 

Make very small particles

 

Add a surfactant

Add a surfactant

Which of the following is a common suspending agent used in suspensions?

 

 

Acetic acid

 

Sodium chloride

 

Carboxymethylcellulose (CMC)

 

Ethyl alcohol

Carboxymethylcellulose (CMC)

Which of the following is a desirable feature in a pharmaceutical suspension?

 

 

Particles that form a compact cake after settling

 

Rapid settling of particles

 

Slow settling and ease of redispersion upon shaking

 

High viscosity that prevents pouring

Slow settling and ease of redispersion upon shaking

Which method can be used to prepare a flocculated oral suspension?

 

 

Adding a flocculating agent such as diluted bentonite magma

 

Adding more preservative

 

Decreasing the density of the medium

 

Increasing the particle size of the drug

Adding a flocculating agent such as diluted bentonite magma

What role does a flocculating agent play in the preparation of flocculated suspensions?

 

 

It serves as a flavoring agent to mask the drug taste.

 

It decreases the solubility of the drug in the suspension.

 

It supports the floc once it is formed to maintain suspension stability.

 

It acts as a primary solvent in the formulation

It supports the floc once it is formed to maintain suspension stability

Which method is not used for inducing flocculation in parenteral suspensions?

 

 

Addition of bentonite magma

 

Addition of electrolytes to reduce electrical barriers

 

Addition of surfactants

 

Alteration of pH to decrease drug solubility

Addition of bentonite magma

What is a disperse system in pharmaceutical terms?

  

 

A gas dispersed in a liquid

 

A powder formulation for reconstitution

 

A solid drug dissolved in a liquid solvent

 

A liquid preparation containing undissolved or immiscible drug particles distributed throughout a vehicle

A liquid preparation containing undissolved or immiscible drug particles distributed throughout a vehicle

What is the dispersed phase in a suspension?

 

 

The continuous phase of the system

 

The internal phase consisting of undissolved solid particles

 

The solvent used to dissolve the drug

 

The medium that contains dissolved substances

The internal phase consisting of undissolved solid particles

What is a major limitation of Stokes' Law in predicting sedimentation in pharmaceutical suspensions?

  

 

It does not account for changes in viscosity

 

It is only applicable to colloidal dispersions

 

It only applies to dilute suspensions of spherical particles in ideal conditions

 

It assumes that particles will dissolve

It only applies to dilute suspensions of spherical particles in ideal conditions

What factor will decrease the sedimentation rate in a suspension according to Stokes' Law?

 

 

 

Increasing the density of the medium

 

Increasing particle size

 

Decreasing the viscosity of the medium

 

Decreasing the density of the medium

Increasing the density of the medium

What is the purpose of flocculating agents in suspensions?

 

 

To increase the viscosity of the suspension

 

To completely dissolve the particles

 

To prevent the formation of a hard cake by creating loose aggregates of particles

 

To enhance the solubility of the drug

To prevent the formation of a hard cake by creating loose aggregates of particles