Buccal + Sublingual Application Flashcards
What is buccal delivery through?
Cheek lining
What is buccal delivery generally used in?
Treatment of chronic disorders when a prolonged release is required
What is sublingual delivery through?
Under the tongue
What is sublingual delivery used for?
Treatment of acute disorders for fast actions
What is the oral cavity lined with?
Uninterrupted mucosal membrane
What does the mucosal lining consist of?
Epithelial membrane
Basement membrane
Lamina propria + submucosa
Describe the non-keratinised oral epithelium
Flexible
Found in soft palate, buccal region
Describe keratinised oral epithelium
Dehydrated
Mechanically tough + chemically resistant
Barrier to drug absorption
Found in gums + hard palate (roof of mouth)
What is the transcellular route?
Crossing the polar + lipid domain of the cell membrane
For lipophilic drugs
What is the paracellular route?
Through intercellular aqueous space between cells
For hydrophilic drugs
What are factors affecting drug absorption?
Lipophilicity
Solubility in saliva
Ionisation
Binding to oral mucosa
Thickness of oral epithelium
Why are conventional oral dosage forms not suitable for buccal drug formulation?
Washing effect of saliva + mechanical stress
What are the most common buccal formulations?
Tablets + patches
What is used in buccal formulation to improve mucosal contact?
Mucoadhesive agents
Penetration enhancers
Enzyme inhibitors
Backing membrane
What are mucoadhesive agents?
Materials that bind to mucus layer of membrane
What do mucoadhesive agents do?
Maintain an intimate + prolonged contact of the formulation with thew absorption site
What are examples of mucoadhesive agents?
Mucoadhesive polymers
PAA
PVA
How do mucoadhesive polymers work?
Polymer hydrates
Swells = flexible chain allows interpenetration between polymer + mucin chain
When are penetration enhancers added?
For systemic effect
What must penetration enhancers be?
Non-irritant
Reversible effects
What are examples of penetration enhancers?
Fatty acids
Surfactants
Bile salts
How do enzyme inhibitors work?
By affecting enzyme activities
Why are enzyme inhibitors used?
To improve buccal absorption of drugs, particularly peptides
What does a backing membrane do?
Prevent drug loss + offers better patient compliance
What are examples of backing membranes?
Carbopol
Magnesium stearate
What is the ideal molecular size for buccal delivery?
Less than 500 Da
What is the ideal log P for buccal delivery?
1.6-3.3
What should the drug be stable for?
Buccal pH 6.4-7.2
Describe buccal tablets
Small, flat, oval shape
Monolithic + 2-layered matrix
What is the limitation of buccal tablets?
Small contact surface
Extended contact = cause irritation
Describe buccal monolithic tablets
Mix of drug with swelling bioadhesive release polymer with bidirectional release
What can buccal monolithic tablets be coated?
On outer or three sides with H2O impermeable hydrophobic substance
Describe buccal 2-layered matrix, local action
Inner layer based on a bioadhesive polymer + outer non-bioadhesive layer containing drug for bi-directional release
Describe buccal 2-layered matrix, systemic action
Drug loaded into inner bioadhesive layer
Outer layer is inert + acts as protective layer
Describe buccal patches/films
Long, flat, thin film with high SA
Why do buccal patches have higher patient compliance?
Physical flexibility + softness
What does buccal patches consist of?
Impermeable backing layer + drug-containing layer that has mucoadhesive properties
Describe the drug absorption of sublingual
Rapid due to relatively thin + high permeable sublingual mucosa + profuse blood supply
What is the sublingual route effected by?
Constantly washed by saliva + movements of the tongue
What is critical in sublingual formulation because there is rapid disintegration + dissolution?
Small tablet size
Low hardness
High porosity
Because sublingual tablets have a high porosity + low hardness, what does it mean?
More friable
= need to be careful with packaging
What do you advise the patient with sublingual tablets?
Avoid chewing or swallowing the tablets
Avoid eating/drinking during administration
