Home' Australian Pharmacist : December 2011 Contents Vol. 30 -- December #12, 2011
Continuing Professional Development
The articles in this series are independently researched and compiled by PSA commissioned authors and peer reviewed.
either matrix or reservoir drug delivery
systems. With the matrix systems
the drug is dispersed in a polymer
along with other excipients, while
in the reservoir systems the drug is
dispersed in a separate layer, which is
sandwiched between two outer layers
containing muco-adhesive excipients.
The patches may incorporate a
backing layer that protects it from
the surrounding oral cavity if strictly
transmucosal delivery is required.
The polymer matrix in which the
drug is incorporated swells and a
network is produced through which
the drug diffuses into the mucosal
membrane.17 Three types of patches
have been developed: (i) patches
with a dissolvable matrix; (ii) patches
with a non dissolvable backing; and
(iii) patches with a dissolvable backing.
Dissolvable matrix patches release the
drug into the entire oral cavity, patches
with a non-dissolvable backing provide
unidirectional release of the drug
into the oral mucosa for a sustained
period of time, while patches with
a dissolvable backing provide rapid
release as the backing dissolves
quite quickly in the oral cavity.6
A flexible buccal patch manufactured
from Eudragit and containing the
b1-adrenergic antagonist, metoprolol,
has been developed and marketed for
the treatment of hypertension.
These can be sprayed directly onto
the sublingual or buccal mucosa
providing either local or systemic
effect. One such spray is the
Nitrolingual pump spray, which
contains the active ingredient glycerol
trinitrate and is sprayed under the
tongue for immediate relief from the
pain of angina.
Lozenges can be used as an
alternative drug delivery device for
tablets and capsules in patients who
are unable to swallow. Sublingual
lozenges are impractical due to
their size; however buccal lozenges
are widely used. They are held
between the check and the gum and
take approximately 30 minutes to
dissolve, however this can vary as
the patient controls dissolution and
absorption by sucking on the lozenge
until it dissolves, which may result
in a high variability in the dosage
delivered each time the lozenge is
administered. An increase in the
amount of sucking by the patient
may also result in the production
of excess saliva, which dilutes the
drug and may result in accidental
A study using unflavoured buccal
lozenges demonstrated that there
was a significant variation in
residence time (two to 10 minutes)
between patients and that stronger
lozenges increased buccal residence
time.18 Despite their drawbacks,
lozenges have been quite successful.
lozenges improved smoking
cessation in low and high dependent
smokers compared to those
receiving the same dose only in a
chewing gum.19 The bioavailability
of fentanyl citrate, used to treat
breakthrough pain, was significantly
improved and the time to achieve a
peak plasma concentration reduced
when delivered by a lozenge via
the oral mucosa, compared to oral
1. Kurosaki Y, Kimura T. Regional variation in oral mucosal
drug permeability. Crit Rev Ther Drug Carrier Syst.
2. Yamamoto A, et al. Absorption of water soluble
compounds with different molecular weights and
[ASU1.7]-eel calcitonin from various mucosal
administration sites. J Control Release. 2001; 76:363.
3. Coluzzi PH, et al. Breakthrough cancer pain: A
randomized trial comparing oral transmucosal fentanyl
citrate (OTFC) and morphine sulfate immediate release
(MSIR). Pain. 2001; 91:123.
4. Heasman PA, et al. Local delivery of chlorhexidine
gluconate (PerioChip) in periodontal maintenance
patients. J Clin Periodontol. 2001; 28:90.
5. Veuillez F, et al. Factors and strategies for improving
buccal absorption of peptides. Eur J Pharm Biopharm.
6. Zhang H, et al. Oral mucosal drug delivery: Clinical
pharmacokinetics and therapeutic applications. Clin
Pharmacokinet. 2002; 41:661.
7. Sayani AP, Chien YW. Systemic delivery of peptides and
proteins across absorptive mucosae. Crit Rev Ther Drug
Carrier Syst. 1996; 13:85.
8. Lahiri A, et al. Buccal nitroglycerin tablets in heart
failure. Ann Intern Med. 1986; 105:141.
9. Abrams J. Glyceryl trinitrate (nitroglycerin) and
the organic nitrates. Choosing the method of
administration. Drugs. 1987; 34:391.
10. Wolf SB, et al. Sublingual misoprostol for labor
induction: A randomized clinical trial. Obstet Gynecol.
11. Hoogstraate AJ, Wertz PW. Drug delivery via the buccal
mucosa. PSTT. 1998; 1:309.
12. Lingstrom P, et al. The release of vitamin C from
chewing gum and its effects on supragingival calculus
formation. Eur J Oral Sci. 2005; 113:20.
13. Rowe RC. By gum -- A buccal delivery system. Drug
Discov Today. 2003; 8:617.
14. Russell MA, et al. Clinical use of nicotine chewing-
gum. BMJ. 1980; 280:1599.
15. Varshosaz J, Dehghan Z. Development and
characterization of buccoadhesive nifedipine tablets.
Eur J Pharm Biopharm. 2002; 54:135.
16. Park CR, Munday DI. Development and evaluation
of a biphasic buccal adhesive tablet for nicotine
replacement therapy. Int J Pharm. 2002;237:215.
17. Gandhi RB, Robinson JR. Oral cavity as a site for
bioadhesive drug delivery. Adv Drug Del Rev. 1994;
18. de Blaey CJ, de Haseth CP. Buccal residence time of
lozenges. Pharm Acta Helv. 1977; 52:116.
19. Shiffman S, et al. Efficacy of a nicotine lozenge for
smoking cessation. Arch Intern Med. 2002; 162:1267.
20. Streisand JB, et al. Absorption and bioavailability of
oral transmucosal fentanyl citrate. Anesthesiology.
1. Which of these is an advantage
of sublingual and buccal drug
a) Avoids first pass metabolism.
b) Alternative route for the delivery of
peptides and proteins.
c) Rapid onset of action.
d) Can be used for patients with
e) All of the above.
2. What is the surface area of the
a) 300,000 cm2.
b) 20,000 cm2.
c) 100,000 cm2.
d) 200 cm2.
e) 500 cm2.
3. Which of the following make
up a chewing gum?
e) All of the above.
A score of 3 out of 4 attracts 0.75 CPD credits.
4. Which of the following delivery
systems can be used in buccal
a) Chewing gum.
e) All of the above.
modes of delivery
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