Bio adhesive d d s

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BIO ADHESIVE DRUG DELIVERY SYSTEM

PUNDARIKA.S.S.PRASAD.K

Y9MPH410

|| SEMESTER, | M.PHARMACY11



Bioadhesive

Bioadhesive polymer

Characteristics of bioadhesive polymers

Mechanism of bioadhesion

Types of Bioadhesive formulations

Targets for Bioadhesive Formulations

Evaluation of bioadhesive drug delivery systems

Conclusion

References

CONTENTS

22



BIOADHESION

Bioadhesion is the process that describes the

adhesion of a polymer to a biological substrate.

Adhesion is defined as the bond produced by

contact between pressure sensitive adhesive and

a substrate.

33



Polymer

Bioadhesive polymer

Biological glues

Bioadhesive polymer

44



Mucosal membranes

These are moist membranes that line passageways

and structures in the body that lead to the outsideenvironment such as the mouth, respiratory tract,

gastrointestinal tract, nose and vagina. They

secrete a viscous fluid known as mucus.

55



Characteristics Of Bioadhesive Polymers

Molecular weight, chain length and cross-linking

density:

Polymers with a high molecular weight

(above 100,000) are desirable because they providemore available bonding sites.

- chen and cyr,1970

Flexibility:Controls the extent of the interpenetration

between the polymers and mucosal/epithelial surfaces

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Hydrophilicity ::To form strong adhesive bonds with

mucosal membranes because the mucus layer contains large amounts of water.

Surface tension :Surface tension is needed to spread the

bioadhesive polymer into the mucosal layer epithelial surface.

Charges and ionization :Polyanionic polymers are preferred

over polycationic and neutral polymers.

77



Polyanions with carboxyl groups are better

candidates than those with sulfates.

Hydrogen bonding :Hydrogen bonding between the

entangled polymer chains forms strong adhesive

bonds, therefore the presence of hydrogen bond ±

forming groups such as OH and COOH groupsare vital in large quantities.

88



Polymers are ideally non toxic and should be non

absorbable from GIT.

Polymers should be nonirritant to mucous

membrane, and form a bonding with mucin-epithelial

cell surfaces.

The polymers must not decompose on storage or

during shelf life of a dosage form.

The cost of the polymers should not be high so that

the prepared dosage form remains competitive.

99



Examples of bioadhesive polymers

Natural polymers : Synthetic polymers :

- tragacanth - cellulose derivatives

- acacia - poly acrylic acid

- sodium alginate - carbomers- lecithin - poly carbophil

- gelatin - poly vinyl alcohol

- chitosan - poly hydroxy ethyl

methyl acrylate

1010



Mechanism of Bioadhesion

Wetting and swelling of polymer

Interpenetration between polymer chain and

mucosal membrane

Formation of chemical bonds between the

entangled chains

1111



Drug release from

muco adhesive drug

delivery system

BIOADHESION

1212



Theories of Bioadhesion

o Wetting theory

o Diff usion theory

o Electronic theory

o Adsorption theory

o Fract ure theory

1313



Non specific interactions

Bioadhesion can be obtained by the

building of either non-specific interactions with the

mucosal surface, which are driven by the physicochemical properties of the particles and the

surfaces

Specific interactionswhen a ligand attached to the particle

is used for the recognition and attachment to a

specific site at the mucosal surface.1414



Types of Bioadhesive formulations

Solid Bioadhesive FormulationsTabletsInsertsLozenges

Semi-solid bioadhesive FormulationsGelsFilms

Liquid Bioadhesive Formulations Viscous liquidsGel forming liquids

1515



Mucoadhesive tablet adhered to

buccal mucosa

Solid bioadhesive formulation

Buccastem tablet

1616



Gels and Films

Crinone gel

Zilactin-B film

1717



Liquid bioadhesive formulations

Artificial tears to treat dry eyes1818



Targets for Bioadhesive Formulations

Bioadhesive formulations have been targeted

to various anatomical locations to aid drugdelivery and absorption. The structure possess

mucous membranes which protect the cell

from damage.

1919



BODY SITE SYSTEMS

Eye Mucoadhesive eye drops /

inserts

Nasal cavity Nasal drug delivery systems

Oral cavity Dental gels / buccal systems

Skin Patches, tapes, dressings

Vagina Local vaginal delivery systems

Rectum Local/systemic rectal delivery

systems 2020



To treat specific conditions affecting the eye.

Such formulations can produce a prolonged or

sustained release of drugs into the eye.

Drugs containing polymers attach to the mucinmucin on

the conjunctival surface by means of non-covalent

bonding.

The polymer is able to remain in contact with the

surface of the eye until mucin replaces itself or until the

pressure of blinking removes the drug from the eye.

Ocular bioadhesive drug delivery

2121



Hypo tears®

Carbopol

Sno Tears®Sno Tears®

pilogel® pilogel®

Examples of ocular bioadhesive formulations

2222



Gel tears and visco tears :

Liquid gel eye drops are used for dry eye

conditions and contain carbomer 980(poly acrylicacid).carbomers lubricate the eye by clinging to the

surface of the eye. This can reduce the frequency of

application into the eye.

2323



Drugs such as antihistamines and steroids areadministered as nasal drops or nasal sprays to treat

conditions affecting the nose.

However nasal mucociliary clearance affects the

retention and therefore the effects of the drugs in

the nose.

One of the most important feature of nasal route

is that it avoids the first-pass metabolism.

Nasal bioadhesive drug delivery

2424



Examples of Nasal bioadhesive formulations

Nasacort®

Rhinocort®

Beconase®

2525



For the first time investigation done by Nagai et.alon peptides and proteins was used is dry powder

formulation containing muco adhesive polymer.

Microspheres are another way of prolonging theresidence time in the nasal cavity.

The addition of muco adhesive excipients

(chitosan) results in clearance rate.

Using mixture of drugs, PEG400 and carbopol 931

they obtain a relatively high and sustained drug

plasma concentration. 2626



Oral bioadhesive formulations are topical products

designed to deliver drugs to the oral cavity which act

by adhering to the oral mucosa and therefore

produce localised effects within the mouth

Oral bioadhesive drug delivery

2727



Corlan®

Bonjela®

Daktarin®

Corsodyl®

Examples of Oral bioadhesive formulations

2828



The buccal mucosa refers to the inner lining of the lips and cheeks. The epithelium of the buccalmucosa is about 40-50 cells thick.

The epithelial cells become flatter as they movefrom the basal layers to the superficial layers

Buccastem - nausea and vomiting

Polyvinylpyrrolidone

Xanthan gum

Suscard - angina

HPMC

Delivery through Buccal mucosa

2929



3030



The buccal route avoid first-pass metabolism. This

region consist of non keratinized epithelium , results

in more permeable to skin.

Drugs with short biological half life, require a

sustained effect and exhibiting poor permeability.

These is good way to deliver via., oral cavity.

Nagai et.al formulated high viscous gel ± carbopol

and hydroxy propyl cellulose ±for ointment dosage

of maintaned on tissue upto 8 hrs.3131



The sublingual mucosa surrounds the sublingualgland which is a mucin-producing salivary glandlocated underneath the tongue.

This mucosa is relatively permeable and gives arapid absorption of many drugs due to its excellent blood supply.

This route is appropriate for many drugs as longas the drug is able to go into solution with saliva inthe mouth.

Example: Glyceryl Trinitrate (GTN) aerosol spray

and tablet -prophylactic treatment of angina.

Delivery through sublingual mucosa

3232



The drug delivery systems used in this case are

required to adhere to the skin for the purpose of:

Collecting body fluids Protecting the skin

Providing local or systemic drug delivery

Bioadhesive products targeted to the skin areformulated into different dosage forms which

include liquids, powders and semi-solids such as

ointments and transdermal patches.

Topical bioadhesive drug delivery

3333



Voltarol® Emulgel

Feldene®

Evorel®

Examples of Topical bioadhesive formulations

3434



The intravaginal route has been used todeliver contraceptives as well as anti-infectiveagents such as antif ungal drugs to exert a localeffect .

Localised application of vaginal formulationsenables the spread of these formulations overthe target area, which allows an effective

therapy.

Bioadhesive polymers are incorporated intovaginal formulations to aid the adhering of thedosage form to its target site.

Vaginal Bioadhesive drug delivery

3535





Among the polymers, poly acrylic acid and

hydroxy propyl methyl cellulose as an ideal

excipients in muco adhesive strength.

Robinson et.al reported on system of treatment

using a gel containing muco adhesive poly

carbophil that remained on vaginal tissue for 3-4

days and hence served as a platform for delivery of drug such as Progesterone.

3737



Bioadhesive polymers are incorporated intorectal suppositories to prolong the retention of the active drug in the rect um.

Prolonged retention in the rect um increasesthe chances of reaching a therapeutic out come

Rectal Bioadhesive drug delivery

3838



Anacal®

Germoloids®

Preparation H®

Examples of Rectal bioadhesive formulations

3939



Hydrogels administered rectally have proven

to be used for drug delivery.

Leede et.al. proposed Hydrogels using

hydroxy ethyl methacrylate cross linked with

ethylene glycol dimethacrylate and including anti

pyrene and theophylline as model drugs providedrate controlled drug delivery.

4040



Name andform

Drug Mucoadhesivepolymers

Applicationsite

Attach tablet Tri amcinoloneacetonide

HPC , carbopol934

Oral cavity

Susadrin tablet Nitroglycerin Synchron(modified HPMC)

Buccal cavity

Buccastem tablet Pro chlorperazinemaleate

Xanthan gum Buccal cavity

Orabase gel - Sodium CMC,gelatin in

polyethylene oilbase.

Oral cavity

Rhinocort powder

Beclomethasone HPC Nasal cavity

Replens gel - Poly acrylic acid Vaginal cavity.

4141



Evaluation of bioadhesive drug delivery systems

The morphological evaluation of drug

carrier(especially micro carriers) include ±

SEM,TEM and FTIR.

Invitro release studies carried out by using-

dissolution apparatus, diffusion method and

incubation of formulation in the medium.

4242



The prepared tablets were attached to freshly

excised intestinal mucosa, which has been spanned

on a stain less steel cylinder(diameter-4.4cm, height-

5.1cm, apparatus usp xxII). There after, the cylinder was placed in dissolution

apparatus according to the USP containing 100 mM

TBS pH 6.8 at 37.5 0.5 ºc. The fully immersed

cylinder was agitated with 250 rpm. The detachment, disintegration and erosion of test

tablets were observed and recorded with in time

period of 10 hours.

Muco adhesive studies

4343



Conclusion

The earlier applications of bioadhesive formulations

mainly involved the oral cavity and the gastrointestinal tract.

These days bioadhesive drug delivery systems have been

developed to target a wider variety of mucosal and epithelial

surfaces, these include the vagina, the skin and the nasalcavity.

Bioadhesive drug delivery also offers a controlled release

of drugs. From a patient¶s point of view this is ideal because

the frequency of drug administration is reduced which in

turn improves patient compliance.

4444



S.P.Vyas and Roop K. Khar-Controlled drug

delivery ±-vallabh prakashan publications -2006

edition ± pg no 257-310.

PHARMATIMES ± vol.38-no.4-april 2006-pg

no. 25-27

Chen J.L. and cyr G.N (1970) adhesion in

biological systems academic press,london,163.

http://www.drugdeliverytech.com/cgi-

bin/articles.cgi?idArticle=159

REFERENCES

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