Suspensions And Emulsions

Question 1

Disperse system in which solid, vehicle-insoluble particles (internal phase) are uniformly suspended by mechanical agitation

Answer 1

Suspensions

Question 2

also called the external phase or dispersion system

Answer 2

continuous phase

Question 3

also called the internal phase or dispersed phase

Answer 3

discontinuous phase

Question 4

In general, three steps in ensuring formulation of suspension:

Answer 4

• Control particle size
• Use of thickeners
• Use of wetting agent

Question 5

The greater the density, the greater the descent

Answer 5

Sedimentation

Question 6

Aggregation will determine the type of suspension

Answer 6

Flocculation

Question 7

To prevent air trapping

Answer 7

Wetting

Question 8

Type of Suspension system

Answer 8

A. FLOCCULATED SYSTEM
B. DEFLOCCULATED SYSTEM

Question 9

Particles appear as floccules like tufts of wool with loose fibrous structure

Answer 9

Flocculated System

Question 10

Flocculated System is also known as

Answer 10

Coagulated or Colloidally Unstable system

Question 11

Particles settle as a dense sediment, which becomes more compact after a given time interval

Answer 11

Deflocculated System

Question 12

Deflocculated System is also known as

Answer 12

Peptized or Colloidally Stable system

Question 13

Methods of Preparation of Suspensions

Answer 13

A. By discipitation method
B. By precipitation method

Question 14

This process is done by dispersing the finely divided powders in an appropriate liquid vehicle.

Answer 14

Discipitation Method

Question 15

This is applicable to those drugs in which its solubility is dependent on pH value.

Answer 15

Precipitation effected by changing the pH

Question 16

Where simple chemistry is involved

Answer 16

By Double Decomposition Method

Question 17

Factors in Suspension Formulation

Answer 17

1) Type of suspension desired
2) Formulation adjuvant
3) Preparation techniques

Question 18

MAIN USE: form mechanical sheath or barrier around particles
• Do not reduce interfacial tension
• Differ in viscosity, thus used in high concentration

Answer 18

Protective colloid

Question 19

increase the viscosity of water by binding water molecules, limiting their mobility or fluidity

Answer 19

Hydrophilic colloids (hydrocolloids)

Question 20

incompatible with quarternary antibacterial agents and other positively charged ions

Answer 20

Anionic hydrocolloids

Question 21

incompatible with negatively charged drugs and excipients

Answer 21

Chitosan

Question 22

Acacia is usually ___% dispersion in water (mucilage).

Answer 22

35%

Question 23

Acacia viscosity is greatest between pH _____

Answer 23

5 - 9

Question 24

Tragacanth is usually used as ___% dispersion in water (mucilage).

Answer 24

6%

Question 25

Tragacanth has an advantage over acacia in that less is needed, and does not contain _____

Answer 25

Oxidase

Question 26

The viscosity of tragacanth is greatest at pH

Answer 26

5

Question 27

polymer that is nonionic and stable to heat and light

Answer 27

Methylcellulose

Question 28

anionic material that is soluble in water

Answer 28

CMC

Question 29

Clay Group – EXAMPLE:

Answer 29

bentonite, veegum, magnesium aluminum alginate

Question 30

Suspending Agents that are strongly hydrated and exhibit thixotropy

Answer 30

Clay Group

Question 31

Official form of bentonite is

Answer 31

5% magma

Question 32

is hydrated to a greater degree than bentonite

Answer 32

Veegum

Question 33

Type of mill used for the reduction of solid particles size and for dispersion of suspensions containing poorly wetted solids.

Answer 33

Rotor Stator

Question 34

These are semi solid systems consisting of fine dispersions made up of either small inorganic particles or large organic molecules, enclosing and interpenetrated by a liquid.

Answer 34

Gels

Question 35

A suspension that appears as masses of gel, consist of floccules of small, distinct particles.

Answer 35

Magmas and Milks

Question 36

Mostly contain finely powdered substances that are insoluble in the dispersion medium and dispersing agents.

Answer 36

Lotions

Question 37

hydrated aluminum silicate clay

Answer 37

Bentonite

Question 38

aluminum – magnesium silicate

Answer 38

Veegum

Question 39

thermodynamically unstable two-phase system consisting of at least two immiscible liquids

Answer 39

Emulsions

Question 40

Purposes of emulsions

Answer 40

1) Increased drug solubility 2) Increased drug stability 3) Prolonged drug action 4) Improved taste 5) Improved appearance

Question 41

appear as translucent or transparent and have droplet diameter in the nanometer range (100Å - 1000Å)

Answer 41

Microemulsion

Question 42

mixtures of a biphasic o/w system stabilized with surfactants

Answer 42

Microemulsion

Question 43

rapid formation of aggregates or emulsion droplets

Answer 43

Coalescence

Question 44

result of the interaction of relativity weak particles

Answer 44

Flocculation

Question 45

IV and oral

Answer 45

o/w type

Question 46

IM

Answer 46

w/o type

Question 47

help the production of stable dispersion by reducing interfacial tension and then maintaining the separation of the droplets by forming a barrier at the interface

Answer 47

Emulsifying agents

Question 48

best emulsifying agent for extemporaneously prepared oral emulsion

Answer 48

ACACIA

Question 49

Increase the viscosity of an emulsion and prevent creaming

Answer 49

TRAGACANTH

Question 50

Provides good emulsion stabilization in a concentration of 0.5 to 1%

Answer 50

GELATIN

Question 51

Used as a primary emulsifier with mineral oil and cod liver oil, and yields an o/w emulsion.

Answer 51

Methylcellulose

Question 52

It tolerates alcohol up to 40%

Answer 52

Carboxymethylcellulose

Question 53

It is usually between 1 and 20 is allocated to an emulsifying agent and represents the relative proportions of lipophilic and hydrophilic molecule, and produce an o/w emulsion.

Answer 53

HLB number

Question 54

HLB 3-6 indicate

Answer 54

lipophilic molecule, produce w/o emulsion

Question 55

HLB 8-18 indicate

Answer 55

hydrophilic molecule, produce o/w emulsion

Question 56

Antifoaming hlb values

Answer 56

1-3

Question 57

Emulsifier (w/o) hlb values

Answer 57

3-6

Question 58

Emulsifier (o/w) hlb values

Answer 58

8-18

Question 59

Wetting Agents hlb values

Answer 59

7-9

Question 60

Solubilizers hlb values

Answer 60

15-20

Question 61

Detergents hlb values

Answer 61

13-16

Question 62

Equipment for emulsions which produce extremely fine particles for moderately viscous emulsions

Answer 62

ULTRASONIFIER

Question 63

ideal for slow mixing of finished emulsions which have been prepared by melting of the waxes

Answer 63

MECHANICAL STIRRERS