Buccal, Rectal and Ocular Drug Delivery Flashcards
When use buccal/ sublingual route? Give an example of each
- Can give to treat locally or systematically
- Local conditions e.g. candida albicans
- Systemic conditions e.g. angina
What are the advantages of using this route?
- Avoids first pass hepatic metabolism
- Rapid onset of action
- Controlled drug release
- Avoid acid/ digestive enzymes in the lower gut therefore you can keep it in the oral cavity and prolong its activity
Structure + function of oral cavity.
- It is the beginning of the alimentary tract
- It is bound by the lips, cheeks, tongue and hard palate sublingual mucosa
- Functions include: processing food,mastification, lubrication, digestion and taste
What are the 3 major glands in the oral cavity? What does each one secrete?
- Parotid gland (watery saliva, response to food)
- Sublingual gland (mucin like saliva)
- Submandibular gland (mixed secretions, some contain digestive enzymes + mucin)
Oral mucosa structure
Squamous stratified epithelium, lamina propria, submucosa
Give examples of keratinised squamous stratified epithelium
gums, hard palate
Give examples of non keratinised squamous stratified epithelium
buccal mucosa, sublingual mucosa
Give examples of specialised mucosa
upper tongue
Role of and types of saliva
- Lubrication, Digestion, Remineralisation of teeth, Antimicrobial
- Two types; serous secretions, mucous secretions
- Serous secretions are watery but contain salts, proteins and the enzyme amylase. Secreted by paratid gland in response to food
- Mucous secretions are viscid and contain salivary mucins. They are secreted by sublingual and minor salivary glands.
- Submandibular releases a mix of both
Typically, humans produce ________ of saliva per day with 80-90|% being ______ saliva
1 litre
serous
What is the salivary pellicle?
A salivary coating of all internal surfaces of the oral cavity e.g teeth. It is protective and lubricating.
Microbiology of oral cavity?
Contains 10^7 to 10^8 bacteria/ml.
300 different species
Also some fungi (candida), viruses (herpes simplex), mycoplasmas and protozoa (entamoeba)
Dental plaque is?
Found on teeth.
A hard, non-shedding surface for microbial colonisation.
Dental plaque is?
Found on teeth.
A hard, non-shedding surface for microbial colonisation. Multiple habitats found on tooth surface, each supporting different populations of oral bacteria
The mucosal barrier is formidable but the major barrier is the stratified epithelia. What are the possible routes for drug permeability?
Lipophilic (transcellular)
Hydrophilic (paracellular)
Active transport?
In terms of absorption, what is the worst and best structure for the drug to go through?
The squamous epithelia is not designed for absorption.
The worst absorption is keratinised epithelia such as gums or hard palate.
The best absorption is through the thinnest areas e.g. buccal and sublingual mucosa.
What type of drug molecules are absorbed best? Log P between? What type of molecules are poorly absorbed?
Small, lipophilic molecules with a log P between 1.6-3.3.
Therapeutic proteins.
What are permeation enhancers? How do they act? What are some examples?
They can increase the absorption of proteins from 1-3% to 10% in vitro.
They act by either:
- increasing the fluidity of the cell membrane
- extracting intra/ inter cellular lipids
- altering the cellular proteins
- altering surface mucins
Examples : bile salts, surfactants e.g. sodium dodecyl sulphate, fatty acids