Oromucosal drug delivery Flashcards Preview

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Flashcards in Oromucosal drug delivery Deck (48)
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1
Q

What are examples of drugs delivered locally using the oral mucosa?

A
  • lidocaine
  • prostaglandin
  • miconazole
2
Q

What are examples of drugs delivered systmemically using the buccal route of the oral mucosa?

A
  • insulin
  • diltiazem
  • bupoprion
3
Q

What are examples of drugs delivered systemically using the sublingual route of the oral mucosa?

A

nitrates

4
Q

Where is the buccal mucosa?

A

on the cheeks and gums in the mouth

5
Q

Where is the sublingual mucosa?

A

under the tongue and the floor of the mouth

6
Q

What is local oromucosal drug delivery used for?

A
  • local anaesthetics,
  • anti infectives
  • antitussives
  • lozenges, gels, gargles and throat sprays
7
Q

What are lozenges?

A

a. k.a troches
- these are solid dosage forms formed using high pressure during tableting to yield slow release
- based on melted flavoured syrup vehicle.
- high sugar contents provide soothing effect
- developing dosage form for a number of other drugs such as sildenafil citrate

8
Q

What is Atridox?

A
  • a SR formulation of doxycycline hyclate 10% used for the treatment of periodontal disease
  • provides slow release of doxycycline for up to 21 days
  • systemic dosing
  • dose required and has side effects
9
Q

What is an example of an adhesive paste?

A
  • oracort which is a mucoadhesive paste to treat mouth ulcers
  • it has two functions:
    1. barrier to speed up healing
    2. anti-inflammatory as it contains the corticosteroid triamcinolone
10
Q

What is an example of an adhesive gel?

A
  • Bonjela
  • contains choline salicylate
  • contains lidocaine in the infant’s version, to treat teething
11
Q

What are the layers of the oral mucosa?

A
  • mucous/saliva
  • superficial layer
  • intermediate layer
  • pickle cell layer
  • basal layer
  • basement membrane
  • lamina propria
  • submucosa
12
Q

what are the main features of the oral mucosa anatomy?

A
  • epithelium comprises stratified squamus cells
  • buccal and sublingual areas are non-keratinised which facilitate rapid drug absorption
  • sublingual permeation and absortpion rates are greater than for buccal
  • buccal permeation rates are between those of the skin and intestine
13
Q

Which route (buccal vs. sublingual) is more appropriate for rapid systemic absorption?

A

sublingual as it contains rapid permeation and absorption rates
it is also highly vasculated so drug will go into systemic circulation

14
Q

Which route (buccal vs. subligual) is more appropriate for sustained release?

A

-buccal as it has a slower permeation rate.

15
Q

How does the permeability barrier of the buccal and sublingual anatomy compare to that of the oral-GIT and the skin?

A
  • buccal and sublingual both comprise of non-keratinised sqaumous epithelium
  • oral-GIT = columnar eithelium
  • skin = keratinocytes
16
Q

How does the thickness in microns of buccal and sublingual anatomy compare to that of oral-GIT and skin?

A
  • buccal: 500-800 (slower permeability)
  • sublingual: 100-200
  • oral GIT: 10-100
  • Skin: 20-100
17
Q

How does the biological environment of the buccal and sublingual anatomy compare to that of the oral-GIT and skin?

A
  • buccal and sublingual: Saliva pH6
  • oral-GIT: fluids, pH1-8
  • skin: little aqueous media, pH 5
18
Q

How does the barrier resistance of the buccal and sublingual anatomy compare to that of the oral-GIT and skin?

A

from order of least resistant:

  1. sublingual
  2. oral-git
  3. buccal
  4. skin
19
Q

How does the the metabolic barrier of the buccal and sublingual anatomy compare to that of the oral-GIT and skin?

A
  • buccal and sublingual: no metabolic barrier
  • oral-GIT: liver, which has high metabolic barrier
  • skin: low metabolic barrier.
20
Q

What are the advantages of systemic delivery through the oromucosal route?

A
  • easily accessible
  • therapy can be terminated
  • avoids FPM
  • eliminates enzyme and acid mediated drug degradation
  • localisation of drug and dosage form
  • rapid onset of action which is useful for drugs like nitroglyercine
  • presence of saliva is useful for dissolving formulations
  • possibility of sustained release
  • delivery of protein/peptide drugs
21
Q

What are the limitations of systemic delivery through the oromucosa route?

A
  • small surface area limits dose of drug
  • drugs can’t be bitter/nauseous
  • drug must be stable at saliva pH
  • dissolution of drug in saliva can result in swallowing
  • buccal mucosa is less permeable compared to other mucous membranes (rectum, intestine, vagina)
  • only drugs absorbed by passive diffusion can be administered
22
Q

What are the advantages specific to the sublingual route?

A
  • accessible
  • relatively permeable
  • rapid absorption
  • acceptable bioavailability
23
Q

What are the specific advantages of the buccal route?

A
  • mucous is more immobilised
  • not washed with large amounts of saliva
  • suitable for SR formulations
  • potential for deliverying peptide drugs
24
Q

What is the mechanism of drug absorption through the oromucosa?

A
  • mainly passive diffusion
  • depends on pKa of drug and pH of medium
  • absorbed via diffusion
  • absorption is proportional to initial concentration and time of contact
  • absorption increases with increased unionised species
25
Q

What are examples of buccal dosage forms?

A
  • conventional buccal tablets and capsules
  • adhesive delivery systems
  • chewing gums
26
Q

What are the problems with using conventional systems in the buccal route?

A
  • stimulate salivation
  • drug solution may be drained
  • poor retention at site
  • discourages speaking and drinking
27
Q

What is bioadhesion?

A

-binding of natural or synthetic polymer to biological substrate

28
Q

What is mucoadhesion?

A

binding of natural or synthetic polymer to a mucosa membrane

29
Q

What is the benefit of bioadhesion and mucoadhesion?

A

-increased retention time at the site of absorption

30
Q

What are advantages of mucoadhesion in buccal drug delivery?

A
  • increases contact time
  • localisation
  • potential for SR (can be designed to stick to buccal membrane for up to 6 hours)
  • avoids metabolising enzymes
  • does not interfere with patient activities although patient acceptability can vary
31
Q

What are the theories to mucoadhesion?

A
  • wettability theory
  • electronic theory
  • adsorption theory
  • diffusion interlocking theory
32
Q

What is the wettabiltiy theory?

A

mucoadhesion is to do with the contact angle/spreadability of the polymer onto the surface of the mucosa membrane

33
Q

What is the electronic theory?

A

mucoadhesion occurs as a result of attraction resulting from electron transfer

34
Q

What is the adsorption theory?

A

mucoadhesion occurs due to ionic, covalent, metallic bonding or VDW interactions

35
Q

What is the diffusion interlocking theory?

A

mucoadhesion occurs as particles of the mucoadhesive diffuse through the membrane and interolock with particles of the membrane

36
Q

What other tests (aside from drug release and dissolution profiles) can help to measure mucoadhesion in vito?

A
  • force of attachment

- rheological measurement

37
Q

What mucous is used in the characterisation of mucoadhesive drugs?

A
  • commerically dried mucous.

- this is rehydrated before testing

38
Q

What in vivo tests can be done on mucoadhesive drugs?

A

-GI transit time

39
Q

What are the three main classifications of bioadhesive polymers?

A
  1. synthetic
  2. natural
  3. semi-synthetic cellulose derivative
40
Q

What are examples of synthetic bioadhesive polymers?

A
  • polyacrylic acid

- polymethacrylate

41
Q

What are examples of natural bioadhesive polymers?

A
  • pectin
  • chitosan
  • xanthan gum
42
Q

What are examples of semisynthetic, cellulose derived bioadhesive polymers?

A
  • HPMC (hyroxypropylmethyl cellulose)
  • HPC (hydroxypropyl cellulose)
  • HEC (hydroxyethyl cellulose)
  • SCMC (sodium carboxymethyl cellulose)
43
Q

What are the two main classes of factors that affect bioadhesion?

A
  • polymer related factors

- environment related factors

44
Q

What are the polymer related factors that affect bioadhesion?

A
  • MW, chain length, conformation
  • functional groups
  • pH/charge
  • concentration of polymer
  • level of hydration
45
Q

What are the environment related factors that affect bioadhesion?

A
  • pH of environment
  • application force
  • contact time
46
Q

What is BUCCASTEM M?

A

-buccal tablet used to treat nausea and vomiting assoc with migraines

47
Q

What does BUCCASTEM M contain?

A
  • each tablet contains prochlorperazine 3mg
  • other ingredients include sugar, povidone K30, xanthan gum, locust bean gum, talc, magnesium stearate and riboflavin sodium phosphate
48
Q

How is BUCCASTEM M administered?

A

-in the buccal cavity between upper lip and top gum