Polymers: Mucoadhesive Dosage Forms COPY Flashcards Preview

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Flashcards in Polymers: Mucoadhesive Dosage Forms COPY Deck (23)
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1
Q

Define: Muscoadhesion

A

Interfacial force between a synthetic or natural polymeric material serving as a dosage form and a mucus layer that covers a mucosal tissue
= There is attraction between the natural mucous layer and the synthetic polymer forms

2
Q

List 3 advantages of mucoadhesive delivery

i.e. using a polymer to adhere to mucosal membranes

A
  1. Increased dosage form residence time
  2. Improved drug bioavailability (as longer residence time)
  3. Reduced administration frequency (as higher bioavailability)
3
Q

Describe the structure of mucosal membranes

A

Layer of soluble secreted mucins
Layer of cell-bound mucins
Epithelial cells

4
Q

Describe the structure of the mucins found on the mucosal membrnes

A

Protein core
Oligosaccharide side chains
Terminal sialic acid at end of side chain

5
Q

Define: Mucin

A

Principle component of mucous

Mucopolysaccharide or glycoprotein

6
Q

List 4 functions of mucosal membranes

A
  1. Protection of epithelial cells from physical and chemical destruction
  2. Lubrication
  3. Wetting
  4. Modulation of water content in the underlying tissues
7
Q

Describe the characteristics of mucosal surfaces

A
  • Dynamic surface that is reformed continuously through the secretion of mucins
  • Relatively short life time as constantly moving and being replaced
  • Efficient semi-permeable barrier system
8
Q

How is mucous constantly moved on?

A

Ciliary cells beat in a formulated fashion

Clears mucous into stomach to be digested

9
Q

List the 4 theories of mucoadhesion

A
  1. Electronic theory
  2. Absorption theory
  3. Diffusion theory
  4. Wetting theory
10
Q

Describe the electronic theory of mucoadhesion

A

Electron transfer between the formulation and mucus result in formation of an electrical double layer at the interface

11
Q

Describe the absorption theory of mucoadhesion

A

Attraction between mucus and mucoadhesive dosage form is achieved via molecular bonding caused by secondary forces such as hydrogen bonding and Van der Waals forced

12
Q

Describe the diffusion theory of mucoadhesion

A

Inter-penetration and physical entanglement of the mucus protein and polymer chains of the dosage form

13
Q

Describe the wetting theory of mucoadhesion

A

Correlates the surface tension of the mucus and the mucoadhesive with the ability of the mucoadhesive to swell and spread on the mucous layer

14
Q

List the stages of mucosal adhesion

A
  1. Contact stage = contact, swelling and wetting

2. Consolidation stage = non-covalent bonds formation, diffusion and inter-penetration

15
Q

List 3 advantages of using sources of animal tissue (slaughterhouse material) to test the performance of mucoadhesive dosage forms

A
  1. No need to breed and kill animals
  2. Cost efficiency
  3. No problems with animal activists
16
Q

List a disadvantage of using sources of animal tissue (slaughterhouse material) to test the performance of mucoadhesive dosage forms

A

Tissues are not always fresh

17
Q

List 4 ways that the performance of mucoadhesive dosage forms can be tested

A
  1. In man
  2. Animal testing
  3. Sources of animal tissue
  4. Visual methods = flow cell method or rotating cylinder method
18
Q

What occurs in the flow cell method?

A

Artificial body fluid solution is run down a slope containing the dosage form and mucosal tissue to test retention time

19
Q

What do the force vs distance graphs show?

A

They show the force required to remove the mucoadhesive from the mucosal membrane at varying distances
The higher the curve, the more force is required to remove it

20
Q

List 4 specific features of mucoadhesive polymers

A
  1. Hydrophilic or water-soluble polymers
  2. Negatively or positively charged groups (polyelectrolytes)
  3. If positive AND negative charged groups are present = poor mucoadhesion
  4. Strong hydrogen bonding groups e.g. carboxyl, hydroxyl, amino-groups
21
Q

List 5 factors which influence mucoadhesion

A
  1. Molecular weight of polymers
  2. Concentration of mucoadhesive
  3. Chain flexibility/cross-linking density of polymers
  4. pH
  5. Presence of non-mucoadhesive co-excipients
22
Q

List 4 solid formulations of mucoadhesives

A
  1. Tablets
  2. Inserts
  3. Lozenges
  4. Films
23
Q

List 3 semi-solid and liquid formulations of mucoadhesives

A
  1. Gels and pastes
  2. Viscous liquids
  3. Gel-forming liquids