3.5

Question 1

In emulsions, the simple oil/water mixture is homogenized, then, if a smaller particle size is desired, the homogenate is passed through a…

Answer 1

colloid mill

Question 2

An emulsion can be reversibly or irreversibly altered by droplet aggregating and its possible sequelae, which includes …

Answer 2

coalescence (two droplets become one) and creaming (droplets rise to the top)

Question 3

interfacial free energy is..

Answer 3

work done to increase the interfacial surface area

Question 4

interfacial tension (liquids) is the _____, it measures the force to overcome in mixing two liquids

Answer 4

surface tension at the surface separating two immiscible liquids

Question 5

To increase the interfacial surface area (dA) between water and oil, energy must be added to the system. This is equal to …

Answer 5

Interfacial free energy (dG)

Question 6

To make emulsification easier is by (decreasing or increasing) interfacial tension, and that’s where surfactants play a role.

Answer 6

decreasing

Question 7

The system free energy is reduced by the reduction of total surface area by (increasing or decreasing) particle size which gives rise to physical instabilities.

Answer 7

increasing

Question 8

Coalesce is ____, and coalescence is from a physical stability point bad.

Answer 8

To grow or come together into one

Question 9

When there is complete coalescence it is called complete phase separation, also referred to “____” of an emulsion and it is irreversible.

Answer 9

breaking

Question 10

_____ results from flocculation and concentration of disperse phase (rise to the top)

Answer 10

creaming

Question 11

Creaming is usually reversible (by agitation) but still not desirable since…

Answer 11

it is a step closer to phase separation and unappealing

Question 12

(High or low) temperatures can accelerate droplet aggregation because ___ temperature increase droplet movement and collisions.

Answer 12

high

Question 13

(Freezing or boiling) can concentrate the droplets, and drive one particle together to each other and separate from other particle.

Answer 13

freezing

water freezes separately

Question 14

_____emulsifiers facilitate droplet formation, and emulsion _____ help prevent flocculation, coalescence, and creaming,

Answer 14

Surfactant; stabilizers

Question 15

____ can be used as both surfactant emulsifier and emulsion stabilizer.

Answer 15

Acacia

Question 16

In emulsions, _______ can absorb at the oil/water interface since they are amphiphilic, they have affinity for both phases.

Answer 16

Surfactant emulsifiers

Question 17

Surfactant emulsifiers are surface active which means they (increase or decrease) interfacial tension

Answer 17

decrease

i.e. reduce force needed to mix immiscible liquids

Question 18

_______ interfere with flocculation, coalescence, creaming, by forming barriers to aggregation and/or by altering the continuous phase.

Answer 18

Emulsion stabilizers

Question 19

Ionic (electric repulsion) of surfactants does it by charge while the non-ionic does it by…

Answer 19

size of hydrophilic component

Question 20

Acacia is an example of ____, where it forms a stabilizing multimolecular film around the droplet

Answer 20

hydrophilic colloid

Question 21

____ similar to hydrophilic colloid in that they form a stabilizing (particulate) film around the droplet such as bentonite, veegum.

Answer 21

Finely divided solids

smaller than oil droplets

Question 22

You can prevent droplets from rising my (increasing or decreasing) viscosity

Answer 22

increasing

Question 23

HLB stands for ____, this system was devised to enable a rational means of surfactant selection for different formulation types.

Answer 23

hydrophilic-lipophilic balance

Question 24

(Higher or lower) the HLB, the Increased surfactant polarity which means increased hydrophilicity.

Answer 24

Higher

Question 25

High HLB, means the lipophilic groups is (larger or smaller) than the hydrophilic group.

Answer 25

smaller

Question 26

Tenet of HLB system: The phase in which the surfactant emulsifier is most soluble becomes the _____ phase of the emulsion.

Answer 26

continuous

Question 27

Emulsifiers with a relatively low HLB will form (w/o or o/w) emulsions.

Answer 27

w/o

Question 28

Emulsifiers with relatively high HLB will form (w/o or o/w) emulsion.

Answer 28

o/w

Question 29

As internal phase volume % increases this increase particle number which increase friction (more particles interaction with each other) and lead to

Answer 29

increase viscosity

Question 30

______ amount of internal phase, where if the internal phase volume percentage gets too high you may have a flip (from W/O to O/W) and vice versa.

Answer 30

``` Phase inversion (change of emulsion type) ```

Question 31

____- clear, thermodynamically stable -- dispersions of two immiscible liquids containing appropriate amounts of surfactants, or surfactants and cosurfactants.

Answer 31

Micro-emulsions (clear, stable)

Question 32

The micro-emulsions formulation is such that the interfacial tension is transiently (negative or positive) (means emulsion forms spontaneously) and near zero after emulsion formation (means emulsion is nearly thermodynamically stable)

Answer 32

negative (negative dE or dG)

Question 33

Micro-emulsions are transparent since they are less than 0.1 microns and droplets are smaller than ...

Answer 33

visible light wavelengths

Question 34

Smaller cosurfactants enable the _____ that allows micro-emulsions to exist.

Answer 34

curvature

Question 35

Avoid excess levigating agent because shear force will (increase or decrease) creating soup-like substance

Answer 35

decrease (you want it paste-like) but to maximize shear force

Question 36

When using viscous vehicles, first dissolve ingredients in a minimum quantity of ____ because it is difficult to dissolve substances in viscous vehicles (e.g. glycerol)

Answer 36

water

Question 37

Useful Tip in compounding Solutions: Add ____ viscosity liquids to ___ viscosity liquids with constant stirring.

Answer 37

high to low

Question 38

Useful tip in compounding elixir, dissolve components _____

Answer 38

Separately (alcohol- soluble to alcohol water-soluble to water)

Question 39

Levigate with water- (miscible or immiscible) levigating agent

Answer 39

water- miscible

Question 40

Dispense suspensions in appropriate containers with adequate _____ for shaking.

Answer 40

head space

Question 41

Storage temperature if too (high or low) crystals can dissolve, then recrystallize to a different size

Answer 41

high

Question 42

Storage temperature if too (high or low) can cause crystals to aggregate

Answer 42

low (aggregate if frozen)

Question 43

Wet gum (____) and Dry gum (continential)

Answer 43

english

Question 44

_____ (dry gum) and English (wet gum)

Answer 44

Continental

Question 45

Continental "dry gum" also known as the _____ method

Answer 45

4:2:1 | 4 parts oil: 2 parts water: 1 part gum