Orally Administered Liposome for Colon Targeting

Presented By:-1. KAZI AMIRUL HOSSAIN

CALCUTTA INSTITUTE OF PHARMACEUTICAL TECHNOLOGY & ALLIED HEALTH SCIENCES

Under the guidance of :- Dr. S. Majumdar

INTRODUCTION

Targeted drug delivery into the colon is highly desirable for local treatment of a variety of colonic diseases such as ulcerative colitis, Crohn’s disease, amoebiasis, colonic cancer, local treatment of colonic pathologies, and systemic delivery of protein and peptide drugs, NSAIDs, steroids.

The colon is believed to be a suitable absorption site for peptides and protein drugs for the following reasons; (i) less diversity, and intensity of digestive enzymes, (ii) less proteolytic activity of colon mucosa than that of small intestine.

ABOUT LIPOSOME

Liposomes are simple microscopic, concentric bilayered vesicles in which an hydrophilic core is entirely enclosed by a membranous lipid bilayer mainly composed of natural or synthetic phospholipids.

Discovered in 1960’s by Bingham and coworkers.

WHY USE LIPOSOMES IN COLONIC DRUG DELIVERY

They can incorporate both hydrophobic and hydrophilic drugs in them.

They can reduce the harmful side effects of various drugs.

They produce site specific drug delivery. They can protect the drug from hostile

environment of stomach and small intestine. They can improve absorbance and bio-

distribution of drugs. They can improve stability of drugs. They can release the drug in appropriate time.

ANATOMY OF COLON:

Ascending colon Transverse colon Descending colon Sigmoid colon

Layers:Serosa – areolar tissue.

Muscularis externa – muscular coat.

Submucosa – connective tissue.

Mucosa – epithelium.

Colonic polyps Diverticulitis Inflammatory bowel disease (IBD).

Chron’s disease. Ulcerative colitis

Colo-Rectal cancer.

Others as amebiasis & Diarrhoea.8

DISORDERS OF COLON

DISORDERS OF COLON INFLAMMATORY BOWEL DISEASE (IBD):-

 Crohn’s disease:-

Ulcerative colitis:-

Example of Drugs Used in Liposome to Treat IBD

Action

Drugs

Anti-inflammatory Amino salicylates:- SulfasalazineCorticosteroids:- Prednisone and hydrocortisone etc.

Immune system suppressors

Azathioprine, mercaptopurine, cyclosporine, infliximab, and methotrexate etc.

Antibiotics Metronidazole and ciprofloxacin etc.

FACTORS GOVERNING COLONIC ABSORPTION

Physiological Factors:-

Small intestinal transit

Colonic transit

Gastric emptying

Stomach and intestinal pH

Colonic micro flora and enzymes

Pharmaceutical factors….(a)Drug candidates

(b)Drug carrier

POLYMERS USED IN LIPOSOME The polymers which are used in liposome plays a major role in

releasing of drug from liposome to colon.

TYPES OF POLYMERS:-1. NATURAL POLYMERS:- EX:- Pectin, chitosan and guar

gum

2. SYNTHETIC POLYMERS:- EX:- Eudragit

pH SENSITIVE POLYMERS:- This type of polymers have a special Characteristics, which release the drug at specific pH.

pH sensitive polymers Optimum pH

Eudragit L 100 6.0

Eudragit s 100 7.0

Eudragit 30 D 5.6

Hydroxypropyl ethyl cellulose phthalate 50

5.2

Cellulose acetate phthalate 4.8

EXAMPLE OF PH SENSITIVE POLYMERS

The various pharmaceutical approaches which have been used for targeting drugs to the colon are mainly based on:

pH dependent

Time-dependent

Bacteria-dependent

Pressure dependent delivery system

DIFFERENT APPROACHES

pH Dependent Process:- In this process the liposomes is coated with pH sensitive polymers, and drug released from liposome at specific pH.

Time Dependent Process:- It is a predetermined process. In this process an appropriate amount of drug is released after a specific time.

Bacteria dependent process:- In this process liposome consist with biodegradable polymers, and released the drug in presence of specific enzyme.

Pressure Dependent Process:- Pressure sensitive liposomes release the drug at a certain pressure limit. Polymers used in this dosage form firm layer that are destroyed by an increase of the luminal pressure of the colon due to peristaltic waves.

CONCLUSION:- Liposome is better drug delivery system for colonic diseases than the other dosage form which are used in colon like enteric coated tablet. In future by addition of other strategies and by minimizing its disadvantages, liposome will find a significant place in colon targeted drug delivery system for various colon diseases like colon cancer, IBD, chron’s disease etc. It has shown that it is very advantageous dosage form, because it reduces the side effects of various toxic drugs specially which are used mainly colon cancer that means anticancer drugs.

ACKNOWLEDGEMENT:-We would like express our special thanks to our teacher Dr. S. Majumder, whose contribution in stimulating suggestion and encouragement, helped us to complete this project successfully.

References:- 1. Vyas S.P, Khar R.K. Targeted and Control Drug Delivery. 1st edition, CBS

publisher and Distributors, New Delhi. 2002: 219-220. 2.J.S Dua, prof. A. C. Rana, Dr. A.k. Bhandari, International journal of

Pharmaceutical studies and researches, Liposome: Application, 2012 : 14-18. 3.Tiwari Gaurav, Tiwari Rucha, Wal Pranay, Wal Ankita, Primary and Novel

Approaches for Colon Targeted Drug Delivery, International Journal of Drug Delivery, 2010,2: 3-5.

4. Khar R.K, Vyas S.P, Ahmad J Farhan, Jain K.G. The Theory and Practice of Industrial Pharmacy. 4th edition, CBS Publishers and Distributers. 2013: 883-884.

5. Hua Susan, orally administered liposomal formulations for colon targeted drug delivery, Oral nanoformulations for colon targeting, 2014, 5: 1-2.

6. Wasnik Shailendra, Parmar Poonam, The design of colon specific drug delivery system and different approaches to treat colon disease, International Journal of Pharmaceutical Sciences Review and Research, 2011, 6: 167-171.

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