L12 - Buccal Drug Delivery

Question 1

why is a chemical being pharmacologucallly active not enough

Answer 1

• drug needs to be delivered to the right location, at the right time, at the desired conc

Question 2

what is the therapeutic window

Answer 2

• or therapeutic range
• range of conc of drug in plasma that produces a therapeutic effect

Question 3

give the location, thickness in mm and type for each of these tissues

gingival

palatal

buccal

sublingual

Answer 3

Question 4

what are the buccal delivery systems

Answer 4

• sublingual tablets
• lozenges
• adhesive tablets
• periodontal realase systems
• chewing gums
• buccal patches
• mouth rinse
• spray
• hydrogels (can be bioadhesive

Question 5

periodontal disease

Answer 5

caused by bacteria in dental plaque

Question 6

what is the optimum range of logP for drugs in the sublingual route

Answer 6

1.6 to 3.3

Question 7

what is the general principal for basic drug and acidic drugs as pH rises

Answer 7

• 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

Question 8

what does the pH partition hypothesis state

Answer 8

• un-ionised forms of drug will diffuse across a lipid membrane

Question 9

what are the absorbition sites in the mouth for buccal drug delivery

Answer 9

• 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

Question 10

sublingual blood drainage

Answer 10

Question 11

what are the advantages of buccal versus GI delivery

Answer 11

• avoid first pass
• prolonged delivery
• unaffected by eating
• avoids oesophageal adhesion
• can be removed once required effect no longer required

Question 12

what are the limitation of buccal versus GI delivery

Answer 12

• 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

Question 13

give example of drugs that use the sublingual delivery route

Answer 13

• 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

Question 14

give example of drugs that use the buccal route

Answer 14

• prochloperazine
  
  • proprietary name - Buccastem, Tementil
  • form - bioadhesive tablet, soln
  • anti-nausease, antipsychotic
• nicotine
  
  • proprietary name - Nicorette
  • form - chewing gum

Question 15

nicotene delivery chewing gum

Answer 15

• 50 - 80% is swallowed and destroyed
  
  • first pass effect
• peak plasma levels
  
  • smoking - 7min
  • chewing gum - 30 min
• variability e.g. chewing methods

Question 16

local vs systemic delivery

Answer 16

• local application of drug to site of action
• system
  
  • systemic circulation to reach target organ

Question 17

apthous stomatitis

Answer 17

mouth ulcer

Question 18

what drugs are used to treat apthous stomatitis

what are the proprietary preperation

Answer 18

• proprietary preperation
  
  • Bonjela Adult
  • Calgel
  • Iglu Gel
  • Anbesol Liquid
• drugs
  
  • antiseptic and local anesthetics typically

Question 19

what are the excipients in treatment for apthous stomatitis

hydrogel formulation

Answer 19

• 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

Question 20

how do hydorgel formulations worm

Answer 20

• drug trapped in polymer chains

Question 21

what is a bioadhesive and what are the consideration when using them

Answer 21

• 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

Question 22

what is the mechanism for mucoadhesion

Answer 22