This document discusses buccal drug delivery and mucoadhesion. It begins by covering topics like the introduction, classification of drug delivery in the oral mucosa (buccal vs sublingual delivery), anatomy of the buccal mucosa, principle of mucoadhesion and theories of mucoadhesion. It then discusses buccal drug delivery in more detail - including its applications, advantages, limitations and various buccal dosage forms. The key highlights are buccal drug delivery avoids first pass metabolism, maintains drug levels longer than sublingual route, and uses mucoadhesive polymers and dosage forms like patches, tablets and gels for drug retention in the buccal cavity.
2. Topics to be cover...
Introduction
Buccal Drug Delivery
Sublingual DrugDelivery
Difference Buccal and Sublingual Drug Delivery
Application of Buccal Drug Delivery
Advantage and Disadvantage
Buccal Dosage Forms
Mucoadhesion
History of Mucoadhesion
Anatomy of Buccal Mucosa
Principle of Mucoadhesion
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3. Introduction
An ideal dosage regimen in the drug therapy of any disease
is the one, which immediately attains the desired
therapeutic concentration of drug in plasma (or at the site of
action) and maintains it constant for the entire duration of
treatment.
Novel drug delivery systems (NDDS) are the system where
the man searches for new method of entry of drug into the
body in order to show its activity in the body.
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4. Classification of Drug delivery in the oral Mucosal
Cavity
1. Buccal drug Delivery
2. Sublingual Delivery
3. Local Delivery
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5. In oral cavity, buccal region deals with an acceptable route
of administration for systemic drug delivery.
Delivery of drug through Buccal mucosa of oral cavity is
called Buccal drug delivery system.
Buccal cavity mucosa was the most convenient and also
easily approachable site for purpose of delivering the
therapeutic agent for both local as well as systemic delivery
used as retentive dosage form.
Mucosa has a rich blood supply so it is highly permeable.
Buccal Drug Delivery
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6. Buccal Mucosa
The buccal mucosa lines the inner cheek and buccal
formulation are placed in mouth between the upper
gums and cheek to treat local and systemic
conditions.
It is richly vascularised and more accessible for the
administration and removal of dosage form. High
patient acceptability, extensive first pass metabolism.
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8. In the sublingual drug delivery where administration of
drug via sublingual mucosa to systemic circulation.
Sublingual mucosa is the membrane of ventral surface of
tongue and floor of the mouth.
Sublingual Drug Delivery
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10. Buccal vs Sublingual Drug Delivery
Buccal Drug Delivery Sublingual Drug Delivery
Delivery of drug through Buccal
mucosa of oral cavity is called
Buccal drug delivery system.
Delivery of the drug through
Sublingual mucosa of oral cavity is
called Sublingual drug delivery
system.
It is a pharmacological route of
administration in which substances
diffuse into the blood through
tissue of inner cheek.
It is a pharmacological route of
administration in which substances
diffuse into the blood through tissue
under the tongue.
Mainly use for Psychiatric drug,
opioid drug, Cardiovascular Drug ,
Hormone Replacement Theory.
Mainly use for cardiovascular drugs,
Steroids, opioid analgesics
Low permeability compare to
sublingual
High permeability compare to
buccal
Less faster compare to sublingual More faster compare to buccal
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12. Advantage of Buccal Drug
Delivery
Avoids 1st pass metabolism
Avoids acid/Enzyme metabolism
Permeation is faster with respect to Skin & TDDS (4-
4000)
Large surface area with respect to sub-lingual mucosa
Good patient compliance with respect to parental
Easy administration & removal in case of toxicity.
For unconscious or comatose patients
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13. Cont...
Easy Access to membrane site so that the delivery system
can be applied, localized and remove easily.
High patient acceptance as compared to the other non-oral
routes of administration of drugs.
Presence of the saliva helps in dissolution of drug.
Improve performance of many drugs, as they are having
prolonged contact time with the mucosa.
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14. LIMITATION of BUCCAL DRUG
DELIVERY
In the buccal membrane there is generally low
permeability.
Drugs with bitter taste or irritant to mucosa or having
noxious smell
Not for children
Eating & drinking difficulty
Salivary erosion & it may enter GIT & choke esophagus
Less surface area than skin
Drugs unstable at Buccal pH(6.5 to 7)
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15. Cont...
It has smaller surface area of membrane of the oral cavity
170 cm2 denotes non-keratinised tissue, including the
buccal membrane.
The secretion of saliva is continuous (0.5-2 L/day) which
cause irritation .
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16. Buccal Dosage forms
There are various types of buccal dosage forms are
available but mainly:-
1. Buccal Tablets
2. Buccal patches/ Films
3. Buccal gel/ Ointment
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20. Mucoadhesion
Mucoadhesive are synthetic or natural polymers which interact
with the mucus layer covering the mucosal epithelial surface and
mucin molecules constituting a major part of mucus.
Two surfaces are held together by interfacial forces which may
consist of valence forces, inter locking action or both.
Mucoadhesive drug delivery system utilize the property of bio
adhesion of certain water-soluble polymers which become
adhesive on hydration.
If adhesive attachment is to a mucous coat the phenomenon is
known as mucoadhesion.
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22. History of Mucoadhesion
Since the early 1980,the concept of Mucoadhesion has
gained considerable interest in pharmaceutical technology.
MDDS have been developed for buccal ,nasal, rectal &
vaginal routes for both systemic & local effects.
MDDS is the best choice for hydrophilic high mol. wt.
substance such as peptides that cannot be administered &
which has poor absorption.
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23. YEAR SCIENTIST STUDY
1847 Sobrero Absorptionof drugs via the
mucous membranes of the oral
cavity
1935/1944 Walton Systemic studies of oral cavity
absorption
1955 Kartzand Barr Reviews of the systemicstudies of
oral cavityabsorption
1966 Gibaldi
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24. Anatomy of Buccal Mucosa
Buccal mucosa lines the inner region of cheeks.
It has mainly two parts & is 500-800um thick & 150Cm^2
approx.
The oral mucosa is divided as
1. Epithelium
2. Basement membrane and connective tissues.
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25. 1. Epithelium
• The oral epithelium of the mouth consists of 40-50 layers
Stratified & Squamous epithelial cell, having thickness of
500-800 µm, which can be keratinized, or non-keratinized.
• Keratinized epithelium is dehydrated, mechanically tough
and chemically resistant. It is found in areas of the oral
cavity subject to mechanical stress such as the mucosa of
the gingiva ( gums ) and hard palate ( roof of mouth ).
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26. Cont...
• Non-keratinized epithelium is relatively flexible and is
found in areas such as the soft palate, the floor of the
mouth, the lips and the cheeks.
• Thus the regions of the oral cavity pertinent to drug
delivery (i.e. the sublingual and buccal regions) have a
non-keratinized epithelium.
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27. 2. Basement membrane and
connective tissue
The basement membrane is a continuous layer of
extracellular materials and form a boundary between the
basal layer of epithelium and the connective tissues.
This basal complex anchors the epithelium to the
connective tissue and supplements to the barrier functions
of the superficial layers of the epithelium to prevent some
large molecules from passing the oral mucosa.
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28. Cont...
The bulk of connective tissue consists of a collagen fibre
network, this organization of which determines
mechanical stability, resistance to deformation and
extendibility of the tissue.
Most likely, the connective tissue, along with the
basement membrane, is not consider to influence the
diffusion of most compounds of pharmacological interest
although this two regions may limit the movement of
some macro molecules and complexes.
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30. Principle of Mucoadhesion
MUCO
Inner layers called mucosa
Inner epithelial Cell lining is Covered with viscoelastic fluid.
Secreted by Goblet cells
Composed of water and mucin (an anionic polyelectrolyte )
Other components include proteins, lipids,
mucopolysaccharides, electrolytes.
Thickness varies from ≈40–50 μm to ≈300 μm
Main role is protective and lubricates
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31. ADHESIVE
Tendency of substance to remain adhered to surface.
If substance adhere to Biological membrane it is called
as Bio adhesion .
If substance adhere to Biological mucosal layers it is
called as Mucoadhesion.
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32. THEORIES OF MUCOADHESION
There are mainly five main theories of mucoadhesion,
those are:-
1. Wetting theory .
2. Diffusion theory .
3. Electronic theory .
4. Adsorption theory .
5. Fracture theory .
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33. Wetting theory
This theory is predominantly applicable to the liquid
bioadhesive system and analyses the adhesive and contact
behavior in terms of the ability of a liquid or a paste to
spread over a biological system.
The wetting theory applies to liquid systems which
present affinity to the surface in order to spread over it.
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34. Cont...
This affinity can be found by using measuring techniques
such as the contact angle.
The general rule states that the lower the contact angle, the
greater is the affinity.
The wetting theory calculates the contact angle and the
thermodynamic work of adhesion.
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35. It is best applied to liquid or low-viscosity bioadhesive.
The contact angle should be equal or close to zero to
provide adequate spreadability.
If a bioadhesive material is to successfully adhere to a
biological surface, it must first dispel barrier substances
and then spontaneously spread across the underlying
substrate, either tissue or mucus.
The spreadability coefficient can be calculated from the
difference between the surface energies γ B and γA and the
interfacial energy γAB, as indicated in the equation given
below.
SAB =γB –γA –γAB
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36. This theory explains the importance of contact angle and
reduction of surface and interfacial energies to achieve
good amount of mucoadhesion.
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37. Diffusion theory
Diffusion theory describes the interpenetration of both polymer
and mucin chains to a sufficient depth to create a semi-
permanent adhesive bond.
In bioaddition, the polymer first brought into intimate contact
with the mucous, and over a time the concentration gradient
across the interface cause the diffusion of the chain of the
bioadhesive into the mucous layer.
The rate of diffusion is dependent on the chemical potential
gradient and the diffusion coefficient of a macromolecule
through cross-linked network.
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38. It is believed that adhesion force increase with the degree
of penetration of the polymer chain.
In order for diffusion to occur, it is important that the
components involved have good mutual solubility, that is,
both the bioadhesive and the mucus have similar
chemical structures.
The greater the structural similarity, the better is the
mucoadhesive bond.
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39. Electronic theory
Transfer of electrons occurs on contact of an adhesive
polymer with a mucus glycoprotein network, because of
differences in their electronic structures.
The mutual transfer of electrons results in the formation
of electrical double layer at the interface.
Adhesion occurs due to attractive forces across the
double layer.
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40. Adsorption theory
After an initial contact between the two surfaces, the
material adheres because of surface forces acting
between the atoms in the two surfaces.
• Several forces are develop for two types of chemical
bonds:-
a. Primary chemical bonds of covalent nature, which
are undesirable in bioadhesion because their high
strength may result in permanent bonds.
b. Secondary chemical bonds having many different
forces of attraction including electrostatic forces,
van-derwals forces , hydrogen bonds and hydrophobic
bonds.
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41. FRACTURE THEORY
This is perhaps the most used theory in studies on the
mechanical measurement of mucoadhesion.
It analyzes the force required to separate two surfaces
after adhesion is established.
This force, Sm, is frequently calculated in tests of
resistant to rupture by the ratio of the maximal
detachment force, 𝑭A and the total surface area, Ao,
involved in the adhesive interaction
𝑺M = 𝑭A /AO
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42. Since the fracture theory is concerned only with the force
required to separate the parts, it does not take into account
the interpenetration or diffusion of polymer chains.
Consequently, it is appropriate for use in the calculations
for rigid or semi- rigid bioadhesive materials, in which
the polymer chains do not penetrate into the mucus layer.
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44. Important Questions
What is Buccal Drug Delivery system?
Difference Between Buccal and
Sublingual drug Delivery System
Short note on Mucoadhesion
Theories of Mucoadhesion
Advantage and disadvantage of Buccal
Drug Delivery System
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