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

Define: Muscoadhesion

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

List 3 advantages of mucoadhesive delivery
i.e. using a polymer to adhere to mucosal membranes

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

3

Describe the structure of mucosal membranes

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

4

Describe the structure of the mucins found on the mucosal membrnes

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

5

Define: Mucin

Principle component of mucous
Mucopolysaccharide or glycoprotein

6

List 4 functions of mucosal membranes

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

7

Describe the characteristics of mucosal surfaces

- 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

How is mucous constantly moved on?

Ciliary cells beat in a formulated fashion
Clears mucous into stomach to be digested

9

List the 4 theories of mucoadhesion

1. Electronic theory
2. Absorption theory
3. Diffusion theory
4. Wetting theory

10

Describe the electronic theory of mucoadhesion

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

11

Describe the absorption theory of mucoadhesion

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

Describe the diffusion theory of mucoadhesion

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

13

Describe the wetting theory of mucoadhesion

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

List the stages of mucosal adhesion

1. Contact stage = contact, swelling and wetting
2. Consolidation stage = non-covalent bonds formation, diffusion and inter-penetration

15

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

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

16

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

Tissues are not always fresh

17

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

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

18

What occurs in the flow cell method?

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

19

What do the force vs distance graphs show?

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

List 4 specific features of mucoadhesive polymers

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

List 5 factors which influence mucoadhesion

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

List 4 solid formulations of mucoadhesives

1. Tablets
2. Inserts
3. Lozenges
4. Films

23

List 3 semi-solid and liquid formulations of mucoadhesives

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