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Pharmaceutics II > Week 3 > Flashcards

Week 3 Flashcards

1
Q

Coarse and colloidal disperse systems are [Select all that apply]

  • non-homogeneous
  • homogeneous
  • made of dispersed molecules
  • made from dispersed particle
A

non-homogeneous

made from dispersed particle

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2
Q

Match the type of non-homogeneous disperse system to its composition:
-Suspension
-Emulsion
-Aerosol
Options:
-an immiscible liquid dispersed in a liquid
-an immiscible solid dispersed in a liquid
-an immiscible solid/liquid dispersed in air

A

suspension : an immiscible solid dispersed in a liquid

emulsion: an immiscible liquid dispersed in a liquid
aerosol: an immiscible solid/liquid dispersed in air

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3
Q

The force causing interfacial or surface tension is due to?

A

immiscibility of the two surfaces causing molecules on the surface/ interface to pull inward

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4
Q

Interfacial tension occurs between any _________, while surface tension occurs between _______

A

two surfaces except for air

any surface and air

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5
Q

The kinetic properties that affect a two phase non-homogeneous system are

A

gravity and Brownian motion

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6
Q

Brownian motion _____ a disperse system stability by causing particles to move __________ in the dispersion medium

A

decreases

in all directions

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7
Q

Gravity _____ a disperse system stability by causing particles to move ______ in the dispersion medium.

A

decreases

up or down

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8
Q

Based on the Stokes equation, what happens to the settling rate when the viscosity of the dispersed system increases?

  • increases
  • decreases
  • remains the same
A

decreases

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9
Q

Based on the Stokes equation, what happens to the settling rate when the particle size of the dispersant decreases?

  • increases
  • decreases
  • remains the same
A

decreases

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10
Q

Based on the Einstein equation, what happens to the rate of Brownian motion when the particle size of the dispersant increases?

  • increases
  • decreases
  • remains the same
A

decreases

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11
Q

Based on the Einstein equation, what happens to the Brownian motion displacement when the dispersant’s particle size increases?

  • increases
  • decreases
  • remains the same
A

decreases

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12
Q

The electric property that effects a two phase non-homogeneous system is?

A

zeta potential

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13
Q

Zeta potential values of 50 mV indicate _________ between the particles, while 0 mV zeta potential values indicate ____________ between the particles.

A

high repulsive forces

high attractive forces

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14
Q

Particles that have very high repulsive forces will:
form loose sediments that do disperse
form strong sediments that do disperse
form strong sediments that do not re-disperse
form loose sediments that do not re-disperse

A

form strong sediments that do not re-disperse

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15
Q

Particles which have no repulsive forces, very high attractive forces, and 0 mV zeta potential will:
form loose sediments that do disperse
form strong sediments that do disperse
form strong sediments that do not re-disperse
form loose sediments that do not re-disperse

A

form strong sediments that do not re-disperse

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16
Q

Particles which have optimized or adjusted zeta potential will:
form loose sediments that do disperse
form strong sediments that do disperse
form strong sediments that do not re-disperse
form loose sediments that do not re-disperse

A

form loose sediments that do disperse

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17
Q 
Optimizing the zeta potential means adjusting the zeta potential to have:
low attractive forces to form flocs 
high attractive forces to form flocs 
high repulsive forces to form flocs 
no attractive forces to form flocs
A

low attractive forces to form flocs

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18
Q 
Examples of irreversible phase separation in non-homogeneous two-phase dispersions include:
Caking and cracking 
Caking and creaming 
Floc formation and cracking 
Floc formation and creaming
A

Caking and cracking

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19
Q

Reducing which of the following will improve the stability of non-homogeneous 2 –phase disperse systems? Select all that apply.

  • Interfacial tension
  • Particle aggregation
  • Particle deaggregation
  • Floc formation
A

Interfacial tension

Particle aggregation

20
Q 
Match the colloid type with its stabilization mechanism in non-homogeneous two-phase dispersions.
Soluble colloids
Association colloids
Particulate colloids
options:
Steric and/or Electrostatic stabilization
Steric stabilization
Electrostatic stabilization
A

Soluble colloids: Steric stabilization
Association colloids: Steric and/or Electrostatic stabilization
Particulate colloids: Electrostatic stabilization

21
Q

Which of the following colloid(s) enhance stability without affecting the viscosity of the dispersion medium?
Soluble colloids
Association colloids
Particulate colloids

A

Association colloids

22
Q 
Zwitterionic surfactants or association colloids exhibit?
negative charges 
positive charges 
both negative and positive charges 
neither negative nor positive charges
A

both negative and positive charges

23
Q

HLB is the system of rating surfactants in terms of their ________ which helps identify their function in various disperse systems.

A

hydrophilicity and lipophilicity

24
Q

Viscosity is defined as the rate of?

A

flow of fluids

25
Q

Viscosity of Newtonian fluids:
changes with changes in shear rate
changes with changes in shear stress
does not change with changes in shear rate
cannot be predicted based on shear stress

A

does not change with changes in shear rate

26
Q

The viscosity of pseudoplastic fluids:
decreases with a reduction in shear rate
increases with a reduction in shear rate
decreases with an increase in shear rate
increases with an increase in shear rate

A

decreases with an increase in shear rate

27
Q 
Which type of rheology is usually avoided in the pharmaceutical setting?
Newtonian 
Plastic 
Thixotropic 
Dilatant
A

Dilatant

28
Q 
Components of an emulsion include an \_\_\_\_\_ dispersed in an \_\_\_\_\_\_ using an \_\_\_\_\_\_\_
options:
internal phase
emulsifier
external phase
A

internal phase, external phase, emulsifier

29
Q 
Emulsions typically contain?
 two immiscible solids 
a liquid in an immiscible solid 
two immiscible liquid 
a solid in an immiscible liquid
A

two immiscible liquid

30
Q 
Emulsions can be characterized based on. [Select all that apply]
their phases 
the size of the dispersed particles 
the viscosity of the external phase 
the type of emulsifier used
A

their phases

the size of the dispersed particles

31
Q

The external phase in an O/W emulsion is?
oil
water
wetting agent

A

water

32
Q

Colloidal emulsions have dispersed phase sizes that are?

A

10-200 nm

33
Q

The dominant force in coarse emulsions is ___________ due to the size of the _____________.

A

gravity; dispersed particle

34
Q

Microemulsions tend to have higher/lower stability due to higher/lower surfactant concentration.

A

higher; higher

35
Q

T/F Emulsions can sometimes be used to deliver only in the internal phase

A

true

36
Q

T/F Emulsions can carry high drug concentrations

A

false

37
Q

A lipophilic drug delivered in an emulsion requires an ___ as the internal phase of the formulation

A

oil

38
Q

A surfactant with an HLB of _____________ is needed to prepare an O/W emulsion.

A

8-19

39
Q

Which type of colloids must be used in an emulsion to stabilize the interface and reduce interfacial tension?
soluble colloids
association colloids
particulate colloids

A

association colloids

40
Q 
Which type of excipient will promote flocculation in emulsions?
Preservative 
Antioxidant 
Particulate hydrocolloid 
Tonicity agent
A

Particulate hydrocolloid

41
Q 
Reversible physical stability issues with emulsions include\_\_\_\_\_\_\_\_\_\_\_. [Select all that apply]
flocculation 
cracking 
creaming 
coalescence
A

flocculation and creaming

42
Q

Oxidation in emulsions is commonly associated with?

A

oil

43
Q

T/F All coarse emulsions can be administered parenterally by the IV route.

A

false

44
Q 
A major concern with microemulsion use parenterally is \_\_\_\_\_\_\_\_\_\_\_. 
options:
low stability due to gravity 
high surfactant concentration 
risk of pulmonary embolisms 
risk of microbial contamination
A

high surfactant concentration

45
Q

Drug E is available as a W/O emulsion. Drug E has a MW of 310 Da and a log Ko/w of 0.5. What will be the rate limiting step for Drug E in this dosage form?
Diffusion coefficient
Both diffusion coefficient & partition coefficient
Partition coefficient
Neither diffusion coefficient & partition coefficient

A

Partition coefficient

Pharmaceutics II (9 decks)

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