This document discusses pharmaceutical approaches to colon targeted drug delivery systems. It begins with an introduction to colon targeted drug delivery and the advantages of this approach. It then describes the anatomy and physiology of the colon, factors governing colonic drug delivery, and various strategies that can be used for targeting drugs to the colon. These strategies include pH dependent delivery, time dependent delivery, pressure dependent delivery, and bacteria dependent delivery. The document also discusses different approaches for colon targeting, including coating with pH sensitive polymers and formulation of timed release systems. It reviews evaluation methods and some marketed products for colon targeted delivery systems, and concludes with discussing future prospects for this drug delivery approach.

1. PHARMACEUTICAL
APPROACHES TO
COLON TARGETED
DRUG DELIVERY
SYSTEM
Anirban Saha
M.Pharm
(Pharmaceutics)
Year- 1st
, Semester- 2
Amity University.
sahaanirban18@gmail.
AMITY
INSTITUTE OF
PHARMACY

2. Introduction
Anatomy and Physiology of colon
Factors governing Colonic drug delivery
Strategies for Targeting drug to colon
Targeting Approaches to colon
Evaluation of C.T.D.D.S
Marketed Preparation
Applications
Future Prospects
Conclusion
References
2
-:CONTENTS:-

3. 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.
3
INTRODUCTION

4. 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.
4
ADVANTAGES

5. 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.
5
DISADVANTAGES

6. 6
 Location-in abdominal cavity
 Made up of-
 Serosa – areolar tissue.
 Muscularis externa – muscular
coat.
 Submucosa – connective tissue.
 Mucosa – epithelium.
ANATOMY AND PHYSIOLOGY OF COLON

7. 7

8.  Ascending colon
 Transverse colon
 Descending colon
 Sigmoid colon
8
Contd…

9. 9
THE PH RANGES OF GIT

10. 10
Length and internal diameter colon &
small intestine

11.  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.
11
FUNCTIONS OF COLON

12. Ulcerative colitis.
Inflammatory bowel disease (IBD).
Chron’s disease.
Colo-Rectal cancer.
Others as amebiasis & Diarrhoea.
12
DISORDERS OF COLON

13.  Physiological Factors :-
Small intestinal transit
Colonic transit
Gastric emptying
Stomach and intestinal pH
Colonic micro flora and enzymes
 Pharmaceutical factors :-
Drug candidates
Drug carrier
13
FACTORS GOVERNING COLONIC DRUG
DELIVERY

14.  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).
14
Strategies for targeting Drug to Colon

15. The most commonly used targeting mechanisms are:-
 pH – dependent delivery
 Time - dependent delivery
 Pressure- dependent delivery and
 Bacteria—dependent delivery
15
Continue…

16. 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

17. 17

18.  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.
18
1.Covalent linkage of the drug with a carrier

19. 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.
19
Similarly

20.  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

21. 21

22. 22

23. 23

24. 24
Biodegradable poly saccharides

25. 25
EVALUATION OF COLON TARGETED
DRUG DELIVERY

26. MARKETED PREPERATION
MARKETED PRODUCTS
26

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28. 28
CONCLUSION

29. 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

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