Dispersed Systems: Colloids

Descrição

1. To understand the definition of colloids. 2. To understand the unique properties of colloids 3. To get familiar with the classifications of colloidal systems. 4. To identify colloidal dosage forms and their methods of compounding or preparation: - Gels - Magmas - Nano/Micro delivery systems 5. To Understand important physical properties of colloids.
Crystal Yu
Quiz por Crystal Yu, atualizado more than 1 year ago
Crystal Yu
Criado por Crystal Yu mais de 6 anos atrás
124
0

Resumo de Recurso

Questão 1

Questão
Solutions are known as [blank_start]molecular dispersions[blank_end] in which the size of the internal phase is [blank_start]< 1 nm[blank_end].
Responda
  • molecular dispersions
  • < 1 nm

Questão 2

Questão
Molecular dispersions can pass through [blank_start]ultrafilters[blank_end] and semi-permeable membranes. They undergo rapid [blank_start]diffusion[blank_end] and are invisible under an [blank_start]electron microscope[blank_end].
Responda
  • ultrafilters
  • diffusion
  • electron microscope

Questão 3

Questão
Most pharmaceutical suspensions and emulsions are [blank_start]coarse[blank_end] dispersions in which the size of the internal phase is [blank_start]> 500 nm[blank_end].
Responda
  • > 500 nm
  • coarse

Questão 4

Questão
Coarse dispersions are visible under a [blank_start]light microscope[blank_end] and do not [blank_start]diffuse[blank_end]. Particles can be separated via [blank_start]filtration[blank_end].
Responda
  • light microscope
  • diffuse
  • filtration

Questão 5

Questão
Colloids are also known as [blank_start]fine dispersions[blank_end]. Examples of colloids include [blank_start]micelles[blank_end] and [blank_start]microemulsions[blank_end].
Responda
  • fine dispersions
  • micelles
  • microemulsions

Questão 6

Questão
Colloids are dispersed systems in which the size of the internal phase is between [blank_start]1 nm[blank_end] and [blank_start]500 nm[blank_end].
Responda
  • 1 nm
  • 500 nm

Questão 7

Questão
Colloids are visible through [blank_start]electron microscopes[blank_end], they diffuse [blank_start]slowly[blank_end], and are separated by ultrafiltration or [blank_start]dialysis[blank_end]
Responda
  • electron microscopes
  • slowly
  • dialysis

Questão 8

Questão
Particle shape of colloids will depend on the phase of the medium. This will affect the [blank_start]viscosity[blank_end].
Responda
  • viscosity

Questão 9

Questão
There are three different classifications of colloids: 1. [blank_start]Lyophilic[blank_end] colloids 2. [blank_start]Lyophobic[blank_end] colloids 3[blank_start]. Association[blank_end] colloids
Responda
  • Lyophilic
  • Lyophobic
  • . Association

Questão 10

Questão
Lyophilic colloids: [blank_start]Large organic[blank_end] molecules capable of being [blank_start]solvated[blank_end] or [blank_start]associated[blank_end] with the molecules of the continuous phase. (example: acacia or gelatin)
Responda
  • Large organic
  • solvated
  • associated

Questão 11

Questão
Lyophilic colloids are prepared by [blank_start]simple mixing[blank_end]. They are thermodynamically [blank_start]stable[blank_end] and reconstitution is possible.
Responda
  • simple mixing
  • stable

Questão 12

Questão
Lyophilic colloids [blank_start]increase[blank_end] the viscosity of the medium and has two different phases the gel and solution phase
Responda
  • increase

Questão 13

Questão
The solution-gel transition in a lyophilic colloid is dependent on the [blank_start]critical gelation concentration[blank_end] and [blank_start]temperature[blank_end]
Responda
  • critical gelation concentration
  • temperature

Questão 14

Questão
[blank_start]Lyophobic colloids[blank_end] are thermodynamically unstable and reconstitution is not possible.
Responda
  • Lyophobic colloids

Questão 15

Questão
Lyophobic colloids require stabilization to prevent [blank_start]coalesence[blank_end].
Responda
  • coalesence

Questão 16

Questão
[blank_start]Association[blank_end] colloids are amphiphilic compounds such as micelles and vesicles.
Responda
  • Association

Questão 17

Questão
Colloidal dosage forms include: A) [blank_start]Gels[blank_end] B) [blank_start]Magma[blank_end] C) [blank_start]Nano-delivery[blank_end] systems
Responda
  • Gels
  • Magma
  • Nano-delivery

Questão 18

Questão
A gel is a solid or semisolid system of at least two constituents: a [blank_start]condensed mass[blank_end] enclosing or interpenetrated by [blank_start]water[blank_end]
Responda
  • condensed mass
  • water

Questão 19

Questão
[blank_start]Jelly[blank_end]: when liquid is present. [blank_start]Xerogel[blank_end]: When liquid is removed from a gel and only the framework remains. Examples include gelatin sheets, tragacant ribbons, and acacia tears.
Responda
  • Jelly
  • Xerogel

Questão 20

Questão
[blank_start]Imbibition[blank_end]: Taking up liquid without a change in size [blank_start]Swelling[blank_end]: Taking up liquid with a change in size [blank_start]Synersis[blank_end]: Loss of liquid
Responda
  • Imbibition
  • Swelling
  • Synersis

Questão 21

Questão
Gels: One phase systems - [blank_start]Macromolecules[blank_end] bond together with van der Waals forces to form [blank_start]amorphous[blank_end] or [blank_start]crystalline[blank_end] regions (Ex. tragacant and carboxymethylcellulose)
Responda
  • Macromolecules
  • amorphous
  • crystalline

Questão 22

Questão
Gels: Two phase systems - [blank_start]Floccules[blank_end] of small particles form and create a network - Not always stable - [blank_start]Thixotropic[blank_end] - Examples of this are aluminum hydroxide gel, bentonite magma, and magnesium magma
Responda
  • Floccules
  • Thixotropic

Questão 23

Questão
In gels, two phase systems are usually [blank_start]inorganic[blank_end] and single phase systems are usually [blank_start]organic[blank_end],
Responda
  • inorganic
  • organic

Questão 24

Questão
Examples of [blank_start]Hydrogels[blank_end]: Pectin paste, tragacanth jelly, and methylcellulose
Responda
  • Hydrogels

Questão 25

Questão
Examples of [blank_start]Organogels[blank_end]: Petrolatum, mineral oil/polyethylene gel, and cocoabutter
Responda
  • Organogels

Questão 26

Questão
With the acrylic acid-based polymer [blank_start]carbomer[blank_end], maximum viscosity will happen at pH [blank_start]7[blank_end].
Responda
  • carbomer
  • 7

Questão 27

Questão
Carbomers Are very [blank_start]hygroscopic[blank_end], so should be kept in tight containers before use, or they will get sticky.
Responda
  • hygroscopic

Questão 28

Questão
A commonly used gelling agent known as [blank_start]Alginic acid[blank_end] is taken from seaweed. It needs [blank_start]calcium salts[blank_end] to form the gel.
Responda
  • Alginic acid
  • calcium salts

Questão 29

Questão
A commonly used gelling agent known as [blank_start]methyl cellulose[blank_end] slowly hydrates in hot water and is then stirred with cold water to prompt dissolution
Responda
  • methyl cellulose

Questão 30

Questão
A commonly used gelling agent known as [blank_start]hydroxyethylcellulose[blank_end] hydrates and swells in cold water. It makes thinner gels that are compatible with water and alcohol.
Responda
  • hydroxyethylcellulose

Questão 31

Questão
A commonly used gelling agent known as [blank_start]hydroxypropylcellulose[blank_end] hydrates and swells in water and hydroalcoholic solvents. Good for high amount of drugs and makes thin gels.
Responda
  • hydroxypropylcellulose

Questão 32

Questão
The only true example of an organogel is [blank_start]plastibase[blank_end] or [blank_start]jelene[blank_end]. This gel can be heated to about 60 degrees without loss of consistency.
Responda
  • plastibase
  • jelene

Questão 33

Questão
[blank_start]Aluminum hydroxide[blank_end] gel is an antacid and may cause constipation. May interfere with the bioavailability of [blank_start]tetracycline[blank_end] by [blank_start]chelating[blank_end].
Responda
  • Aluminum hydroxide
  • tetracycline
  • chelating

Questão 34

Questão
[blank_start]Milk of Magnesia[blank_end] is an antacid with anti-constipating effects. It does not cause constipation.
Responda
  • Milk of Magnesia

Questão 35

Questão
Gels should be kept in tight containers and should be observed for: - [blank_start]Shrinkage[blank_end] - Separation of liquid - [blank_start]Discoloration[blank_end] - [blank_start]Microbial growth[blank_end]
Responda
  • Shrinkage
  • Discoloration
  • Microbial growth

Questão 36

Questão
If the particle size in a two-phase system is large, the gel is referred to as a [blank_start]magma[blank_end]
Responda
  • magma

Questão 37

Questão
[blank_start]Microemulsions[blank_end] are thermodynamically stable, optically transparent mixtures of a biphasic o/w or w/o system stabilized with [blank_start]surfactants[blank_end].
Responda
  • Microemulsions
  • surfactants

Questão 38

Questão
Microemulsions are prepared using surfactants with an HLB range of [blank_start]15[blank_end] - [blank_start]18[blank_end] such as polysorbate 60 and 80
Responda
  • 15
  • 18

Questão 39

Questão
Microemulsions are swollen micelles. The surface area is very [blank_start]high[blank_end] in these microemulsions, therefore [blank_start]interfacial tension[blank_end] has become very low.
Responda
  • high
  • interfacial tension

Questão 40

Questão
Microemulsions are used to enhance [blank_start]oral absorption[blank_end], [blank_start]transdermal delivery[blank_end] as well as targetting anticancer agents
Responda
  • oral absorption
  • transdermal delivery

Questão 41

Questão
[blank_start]Liposomes[blank_end] are used to provide sustained release of some drugs. Provides drug solubilization and protection, sustained and controlled release, [blank_start]targeted delivery[blank_end], and drug internalization.
Responda
  • Liposomes
  • targeted delivery

Questão 42

Questão
Depending on the process used for their preparation, two types of nanoparticles can be formed. - [blank_start]Nanocapsules[blank_end] - [blank_start]Nanoparticles[blank_end]
Responda
  • Nanocapsules
  • Nanoparticles

Questão 43

Questão
Nanocapsules coats the drug in a manner that is similar to that of an [blank_start]egg[blank_end] Nanoparticles have drug dispersed throughout similar to that of a [blank_start]cookie[blank_end]
Responda
  • cookie
  • egg

Questão 44

Questão
[blank_start]Polymeric micelles[blank_end] are better for encapsulating hydrophobic drugs than liposomes because they can leak
Responda
  • Polymeric micelles

Questão 45

Questão
[blank_start]Tyndall effect[blank_end]: Scattering may be described in terms of Turbidity which is the fraction decrease in light intensity due to scattering to all directions.
Responda
  • Tyndall effect

Questão 46

Questão
Bigger particles = [blank_start]Lower[blank_end] diffusion coefficient = [blank_start]slow[blank_end] rate of diffusion
Responda
  • Lower
  • slow

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