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Compounding Exam 2 > Gels > Flashcards

Gels Flashcards

1
Q

ointments are ____% water and ____% oil

A

less than 20% water and greater than 50% oil

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2
Q

true or false

ointments may be medicated or nonmedicated

A

TRUE

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3
Q

3 functions of unmedicated ointments

A

protectants
emollients
lubricants

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4
Q

creams are _____% water and _____% oil

A

greater than 20% water and less than 50% oil

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5
Q

the term “creams” has recently been restricted to _____ emulsions, or aqueous microcrystalline dispersions of long fatty acid chains or alcohols that are ________ and more cosmetically and aesthetically acceptable

A

O/W emulsions

water washable

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6
Q

what is vanishing cream

A

o/w emulsion with lot of water and stearic acid

after applying, the water evaporates and leaves behind a thin residue of stearic acid (or other oleaginous component) on the skin

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7
Q

true or false

creams are more stiff than ointments

A

FALSE - less stiff

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8
Q

**rank the following from most to least stiff

ointment
paste
cream

A

most stiff = paste
ointment
least stiff = cream

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9
Q

pastes contain a larger proportion of ______ than ointments

what does this do

A

solid material

thus, pastes remain in place after applying and are good at absorbing serous secretions

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10
Q

name 2 types of gels

A

-suspensions made of small, inorganic particles

-larger organic molecules, interpenetrated by a liquid

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11
Q

gels are also called ______

A

jellies

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12
Q

_____ have higher water content than ____ and _____

A

gels have higher water content then creams and ointments

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13
Q

advantage of ge;s

A

can be used for several routes of administration

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14
Q

gels can be ____ or ____ systems

A

single phase or two phase systems

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15
Q

explain what single phase gels are

A

large organic molecules uniformly distributed throughout a liquid so that NO APPARENT BOUNDARIES exist between the dispersed molecules and the liquid

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16
Q

explain how gels are thick and viscous

A

the macromolecules contain a “fishnet” and the water molecules get trapped there

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17
Q

the macromolecules in single phase gels can be characteriized as what 3 things and give ex

A

-natural polymers (tragacanth)

-semisynthetic cellulose derivatoves (MC)

synthetic polymers (carbomer polymers)

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18
Q

___macromolecules tend to form clumps of particles when dispersed haphazardly in the solvent

A

hydrophilic

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19
Q

to ensure good dispersion, hydrophilic macromolecules should be…..

A

added slowly with sprinkling and continuous dipserion

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20
Q

if the gel contains __________, it is called a 2 phase system

A

small, discrete particles

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21
Q

true or false

2 phase systems are thixotropic

A

true

ie - they are semisolid when sitting for a while but liquefy when shaken

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22
Q

if the particle size in a 2 phase system is LARGE, what is the gel referred to as?

A

A MAGMA

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23
Q

**give example of a 2 phase gel system and a 1 phase gel system

A

2 phase - magma

1 phase - hand sanitizer

24
Q

***4 examples of gelling agents that can be consumed orally

A

carbopol934P
MC
HPMC
Na CMC

25
Q

“carbomers” are the generic name for a family of polymers known as ________

A

carbopol

26
Q

*****carbomers form ______ aqueous solutions (around what pH??) and thicken at what pH?

A

form aqueous SOLUTION (~3pH) and thicken at higher pH (~6) to form a gel

(add neutralizing agent to raise the pH and thus form a gel)

27
Q

_____are crosslinked polymers

A

carbomers

28
Q

the ability of carbomers to hydrate is reduced by the addition of what?

A

salts (salting out)

29
Q

explain the salting out effect of carbomers when you apply the gel

A

when we apply on the skin, the carbomer will get runnier due to high temperature.

we have salty skin. thus, the water will release out (salting out) of the carbomer (gel) where it was trapped and wont be a gel anymore – becomes runny and thin

gelation = hydration

30
Q

______ derivatives are common gelling agents***

A

cellulose

31
Q

all of the cellulose derivatives except _______ maintain their viscosity over what pH range?

A

except cmc

WIDE PH RANGE
3-11

32
Q

** which cellulose derivative gelling agent has better solubility in cold water and which is better in hot?

what is the concern with how we handle them when preparing gels?***

A

methylcellulose more soluble in COLD WATER, sodium cmc more soluble in HOT WATER

thus, when methylcellulose is being used as a gelling agent, sprinkle in HOT WATER 1ST!!! (80-90 degrees C) – insoluble vehicle to disperse the gelling agent nicely – and then cool it down with cold water with moderate stirring to gain viscosity to become a gel

opposite for CMC/sodium CMC – dispersed in cold water 1st to hydrate ans swell, and then heating to 60 degrees C

33
Q

CMC obtains maximal gelling in how long?

A

1-2 hours

34
Q

___________ are copolymers of polyethylene and polyoxypropylene

A

pluronics (poloxamer gels

35
Q

**poloxamer gels will form ____ gels

what does this mean?

A

thermoreversible!!!!!

they are liquids at cool temps (fridge) and gels at room or body temp – if you put back in fridge - becomes liquid

36
Q

how can poloxamer gels/pluronics be used for IM injections

A

THERMOREVERSIBLE

when you inject, everything should be COLD (bc will be liquid)

when you inject - will become a gel bc body temp – forms a depot for slow release

37
Q

explain how PLO gels are made

A

combining Pluronic F-127 gel (hydrophilic) and a lecithin/isopropyl palmitate solution (lipophilic)

WATER SOLUBLE DRUGS are dissolved in the Pluronic gel (in 1 syringe) and the other syringe will have lecithin/isopropyl

(if the drug was lipophilic you would put with lecitihin)

push the plunger of the 2 syringes back and forth to add shearing stress. this will increase the temp and the pluronic will slowly become a GEL
once all is hard, push to 1 side of the syringe

38
Q

true or false

Pluronic is a lipophilic component of PLO gel

A

FALSE

component of PLO gel, but it’s hydrophilic

39
Q

true or false

when making a PLO gel, lipophilic drugs are dissolved in the syringe with lecithin/isopropyl

A

TRUE

40
Q

what is syneresis of gels

A

SHRINKING

occurs when a gel stands for a while - shrinks naturally and some of the liquid gets pressed out

41
Q

what is bleeding of gels

A

liberation of oil or water from gels

bc of deficient gel structure - NOT from the contraction involved with syneresis/shrinking

42
Q

what is the oppposite of syneresis?

A

SWELLING

43
Q

what is inhibition of gels

A

when gels take up a certain volume of liquid, but NO measurable increase in volume

same as swelling, but volume of the gel does not change

44
Q

*name 2 gelling agents that have better solubility in cold water

A

methylcellulose and poloxamers

45
Q

methylcellulose hydrates and swells in ______ water**

A

HOT

46
Q

after methylcellulose is added to hot water, it is cooled to ____ for around ____***

A

0-10 degrees C for 1 hour

TO COMPLETE GELLATION

47
Q

CMC is dispersed in ____ water to hydrate and swell, followed by heating to _____, with maximum gelling in how long?**

A

COLD
60 degrees C
1-2 hours

48
Q

some gelling agents require a neutralizer (pH adjuster) to create the gel after the gelling agent has been wetted in the dispersing medium

name this gelling agent***

A

carbomer

49
Q

*most gelling agents require how long to COMPLETELY HYDRATE and reach max viscosity and clarity

A

1-2 days (24-48hrs)

50
Q

adding ____ to some gels decreases their viscosity and clarity

A

alcohol

51
Q

VERY IMPORTANT - to be GELS

A

must have hydration!!!!!! lot of water and swelling

52
Q

*****WHAT GELLING AGENT IS MOST SOLUBLE IN HOT WATER

A

sodium CMC

53
Q

**WHAT GELLING AGENTS NEEDS NEUTRALIZER OR PH ADJUSTER ADDED

A

CARBOMER

54
Q

**WHEN GELLING AGENT IS USEFUL TO PREPARE THERMOREVERSIBLE GELS

A

POLOXAMER

55
Q

*****BUD FOR COMPOUNDED TOPICAL GELS WITHOUT ALCOHOL/PRESERVATIVES

A

14 days!
aqueous preparation

56
Q

*****TRUE OR FALSE

carbomer is the generic name of the family of polymers called pluronics

A

FALSE

carbomers are generic name for CARBOPOL

pluronics is brand for POLOXAMERS

57
Q
A

Compounding Exam 2 (9 decks)

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