Colon Specefic Drug Delivery System
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Transcript of Colon Specefic Drug Delivery System
PHARMACEUTICAL APPROACHES TO
COLON TARGETED DRUG DELIVERY
SYSTEM
Anirban SahaM.Pharm
(Pharmaceutics)Year- 1st , Semester- 2
Amity University.sahaanirban18@gmail.
com
AMITY INSTITUTE OF
PHARMACY
IntroductionAnatomy and Physiology of colonFactors governing Colonic drug deliveryStrategies for Targeting drug to colonTargeting Approaches to colonEvaluation of C.T.D.D.SMarketed PreparationApplicationsFuture ProspectsConclusionReferences
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-:CONTENTS:-
Oral route is considered to be most convenient for administration of
drug to patient.
Colon is used as site of Targeted drug delivery.
Colon was considered as a BLACK-BOX , as most of the drug are
absorbed from the upper part of the GI tract.
Prime objective-Beneficial in the treatment of colon diseases.
Increase the pharmacological activity.
Reduce dosing & side effects.
Prevent drug from degradation.
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INTRODUCTION
The site specific delivery of drug to lower part of GIT, for
localized treatment of several colonic diseases.
(ulcerative colitis, Chron's disease, carcinomas and
infections)
Prevent drug from degradation
Ensure direct treatment at disease site.Suitable absorption site for Protein & Peptide drug.Used to prolong the drug therapy. Improved drug utilization.
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ADVANTAGES
Substantial variation in gastric retention time may affect drug delivery.
Diseased condition may affect the colonic transit time and drug release profile.
pH level of colon may vary between individuals due to disease, state and temperature of food consumed.
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DISADVANTAGES
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Location-in abdominal cavity
Made up of-
Serosa – areolar tissue. Muscularis externa – muscular
coat. Submucosa – connective tissue. Mucosa – epithelium.
ANATOMY AND PHYSIOLOGY OF COLON
Provides suitable environment for the growth of colonic
microorganisms,
Absorption of water and Na+ from the lumen, concentrating
the fecal content, Secretion of K+ ions,
Storage reservoir of faecal contents,
Expulsion of the contents of the colon at an appropriate
time.
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FUNCTIONS OF COLON
Ulcerative colitis.
Inflammatory bowel disease (IBD).
Chron’s disease.
Colo-Rectal cancer.
Others as amebiasis & Diarrhoea.
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DISORDERS OF COLON
Physiological Factors :-
Small intestinal transit
Colonic transit
Gastric emptying
Stomach and intestinal pH
Colonic micro flora and enzymes
Pharmaceutical factors :-
Drug candidates
Drug carrier
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FACTORS GOVERNING COLONIC DRUG DELIVERY
An oral colonic delivery system should retard drug release in the stomach and small intestine but allow complete release in the colon.
A variety of strategies has been used and systems have been developed for the purpose of achieving colonic targeting .
These strategies are either drug specific ( prodrug ) or formulation –specific (coated or matrix preparation).
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Strategies for targeting Drug to Colon
The most commonly used targeting mechanisms are:- pH – dependent delivery
Time - dependent delivery
Pressure- dependent delivery and
Bacteria—dependent delivery
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Continue…
The various targeting Approaches of orally administered drugs to the colon include:-
∗ (1)Covalent linkage of a drug with a carrier.
∗ (2)Coating with pH-sensitive polymers.
(3)Formulation of timed released systems.
∗ (4) Exploitation of carriers that are degraded specifically by colonic bacteria.
∗ (5) bioadhesive systems and osmotic controlled drug delivery systems
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TARGETING APPROACHES TO COLON
It involves the formation of a covalent linkage between drug and carrier in such a manner that upon oral administration the moiety remains intact in the stomach and small intestine.
This approach chiefly involves the formation of prodrug, which is a pharmacologically inactive derivative of a parent drug molecule that requires spontaneous or enzymatic transformation in the biological environment to release the active drug.
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1.Covalent linkage of the drug with a carrier
Glycoside conjugates:- Drug is conjugated with Glycoside.
Glucuronide conjugates:- Drug is conjugated with Glucuronide.
Cyclodextrinconjugates:- Drug is conjugated with cyclodextrin.
Dextran conjugates:- Drug is conjugated with dextrin.
Amino-acid conjugates:- Drug is conjugated with amino acid.
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Similarly
Coating with polymers . Coating with pH-sensitive polymers Coating with biodegradable polymers Embedding in matrices Embedding in biodegradable matrices and hydro gels Embedding in pH-sensitive matrices Timed release systems Redox-sensitive polymers Bioadhesive systems Coating with micro particles Osmotic controlled drug delivery
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2 Approaches to deliver the intact molecule to colon
1) Chourasia M.K., Jain S.K.,Pharmaceutical approaches to colon specific drug delivery system,J Pharm PharmaceutSci,2003; 6(1):33-66
2) Madhu E.N., Panaganti S., L. Prabakaran, and Jayveera K. N., Novel Colon Specific Drug Delivery System: A Review, , IJPSR, 2011; 2(10): 2545-2561
3) Tapaswi R.D., Verma P., Matrix Tablets: An Approach towards Oral Extended, Release Drug Delivery, International Journal of Pharma Research & Review, Feb 2013; 2(2):12-24
4) Kshirsagar S.J.,Bhalekar M.R,Umap R.R. In vitro in vivo comparison of two pH Sensitive Eudragit polymers for colon specific drug delivery. J. Pharm. Sci., 2009;1(4):61-70.
5) Shendge R.S., Fatima J., Sayyad, Kishor S., Salunkhe and Bhalke` R.D.,. Development of specific delivery of aceclofenac by using effective binder system of ethyl cellulose. Int. J. Pharm. Bio. Sci., 2010;1(3):1-5.
6) Patel B.P. and Avinash S. Dhake.,Multiparticulate approach: an emerging trend in colon specific drug delivery for Chronotherapy, Journal of Applied Pharmaceutical Science, 2011, 01 (05): 59-63
7) Gang C.F., An, Mei-Juan Zou, Jin Sun, Xiu-HuaHao, Yun-Xia He, Time- and pH-dependent colon-specific drug delivery for orallyadministereddiclofenac sodium and 5-aminosalicylic acid, World J Gastroenterol World, 2004, 10(12): 1769-1774