L12 - Buccal Drug Delivery Flashcards
why is a chemical being pharmacologucallly active not enough
- drug needs to be delivered to the right location, at the right time, at the desired conc
what is the therapeutic window
- or therapeutic range
- range of conc of drug in plasma that produces a therapeutic effect
give the location, thickness in mm and type for each of these tissues
gingival
palatal
buccal
sublingual
what are the buccal delivery systems
- sublingual tablets
- lozenges
- adhesive tablets
- periodontal realase systems
- chewing gums
- buccal patches
- mouth rinse
- spray
- hydrogels (can be bioadhesive
periodontal disease
caused by bacteria in dental plaque
what is the optimum range of logP for drugs in the sublingual route
1.6 to 3.3
what is the general principal for basic drug and acidic drugs as pH rises
- basic drug
- increase in pH, increase in absorbtion
- less ionised
- acidic drug
- increase in pH, decrease in absorbtion
- more ionised, can’t pass through memebrane
what does the pH partition hypothesis state
- un-ionised forms of drug will diffuse across a lipid membrane
what are the absorbition sites in the mouth for buccal drug delivery
- sublingual membrane
- under tongue
- very fast
- buccal membrane
- delivery from the cheek and lip cavity
- slower, better suited to control release
- topical
- delivery from a tablet held within the mouth to the mouth
sublingual blood drainage
what are the advantages of buccal versus GI delivery
- avoid first pass
- prolonged delivery
- unaffected by eating
- avoids oesophageal adhesion
- can be removed once required effect no longer required
what are the limitation of buccal versus GI delivery
- need highly potent drug
- drug highly lipid soluble
- base with a pKa of 8.1
- multilayer membrane barrier
- drug must not taste (organoleptic)
- must be accepable to patient
- requires smaller doses
give example of drugs that use the sublingual delivery route
- glyceral nitrate
- proprietary name - Nittrostate Lenitral Spray, Susadrin
- form - tablet, spray, bioadhesive tablet
- heart failure, high blood pressure, angina
- isosorbide dinatre
- proprietary name - Rosordan, Isocards spray
- form - tablet, spray
- heart failure, esophageal spasms, angina
- bupprenorphine
- proprietary name - temgesic
- form - tablet
- opioid withdrawl symptoms, chronic pain
give example of drugs that use the buccal route
- prochloperazine
- proprietary name - Buccastem, Tementil
- form - bioadhesive tablet, soln
- anti-nausease, antipsychotic
- nicotine
- proprietary name - Nicorette
- form - chewing gum
nicotene delivery chewing gum
- 50 - 80% is swallowed and destroyed
- first pass effect
- peak plasma levels
- smoking - 7min
- chewing gum - 30 min
- variability e.g. chewing methods
local vs systemic delivery
- local application of drug to site of action
- system
- systemic circulation to reach target organ
apthous stomatitis
mouth ulcer
what drugs are used to treat apthous stomatitis
what are the proprietary preperation
- proprietary preperation
- Bonjela Adult
- Calgel
- Iglu Gel
- Anbesol Liquid
- drugs
- antiseptic and local anesthetics typically
what are the excipients in treatment for apthous stomatitis
hydrogel formulation
- taste making
- saccharin
- sorbitol
- menthol
- peppermint oil
- colouring
- sunset yellow
- caramel
- amaranth
- hydration - water
- pH stabalisers
- citric acid
- sodim cytrate
- solubelisers
- polythene glycol (polymer - 0.5 to 5% wt)
- polymer network
- cellulose derivatives, polythene glycol
- thickener/emulsyfying agent
- glycerol, parrafins
how do hydorgel formulations worm
- drug trapped in polymer chains
what is a bioadhesive and what are the consideration when using them
- fix formulation in place for some time
- use glue
- typically polymer that adhers to biological surface (bioadhesion) or to mucosal surface (mucosoadhesions)
- considerations
- strong enough to hold the formulation
- removable when complete
- safe for oral application
- permits drug diffusion
what is the mechanism for mucoadhesion
