Podcast
Questions and Answers
What is the primary advantage of colon mucosa in terms of proteolytic activity?
What is the primary advantage of colon mucosa in terms of proteolytic activity?
What is the primary criteria for selecting a drug for Colon-Targeted Drug Delivery Systems (CDDS)?
What is the primary criteria for selecting a drug for Colon-Targeted Drug Delivery Systems (CDDS)?
Which type of CDDS is dependent on the pH of the gastrointestinal tract?
Which type of CDDS is dependent on the pH of the gastrointestinal tract?
What is the primary mechanism of Transit Time Dependent CDDS?
What is the primary mechanism of Transit Time Dependent CDDS?
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What is the primary advantage of using enteric materials in CDDS?
What is the primary advantage of using enteric materials in CDDS?
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Which type of CDDS is dependent on the enzymatic activity of bacterial enzymes in the colon?
Which type of CDDS is dependent on the enzymatic activity of bacterial enzymes in the colon?
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What is the primary mechanism of Osmotic Pressure-Controlled CDDS?
What is the primary mechanism of Osmotic Pressure-Controlled CDDS?
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What is the primary advantage of using polymeric coatings in CDDS?
What is the primary advantage of using polymeric coatings in CDDS?
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What is the primary disadvantage of Transit Time Dependent CDDS?
What is the primary disadvantage of Transit Time Dependent CDDS?
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What is the primary criteria for selecting a drug for CDDS in terms of first-pass metabolism?
What is the primary criteria for selecting a drug for CDDS in terms of first-pass metabolism?
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Study Notes
Colon Targeted Drug Delivery Systems (CDDS)
- CDDS are gaining importance for systemic and local effects, especially for delivering proteins and peptides.
Anatomy of the Colon
- The colon is the final part of the digestive system, responsible for reabsorbing fluids and processing waste products.
- It consists of four parts: descending colon, ascending colon, transverse colon, and sigmoid colon.
Diseases of the Colon
- Ulcerative colitis
- Crohn's disease
- Colon cancer
- Amoebiasis
Importance of CDDS
- Reduced adverse side effects
- Useful for intentional delayed drug absorption
- Delivery of drug in its intact form close to the target site
Criteria for Selecting Drugs for CDDS
- Drugs poorly absorbed from the upper GIT
- Drugs that degrade in the stomach and small intestine
- Drugs that undergo extensive first-pass metabolism
- Drugs for colon cancer
Approaches to CDDS
1. pH- and Time-Dependent Colonic DDS
- The outer layer dissolves at pH > 5, then the intermediate swellable layer made of an enteric material.
- In another method, succinic acid is used as a pH-adjusting agent with the drug substance in a hard gelatin capsule.
2. pH- and Time-Dependent Colonic DDS
- The outermost enteric layer prevents drug release in the stomach, and the hydrophilic layer dissolves quickly after gastric emptying.
- The onset time of drug release in the intestine can be controlled by the thickness of the acid-soluble layer.
3. Bacterial Enzyme-Dependent Colonic DDS
- The microflora of the colon (10^11-10^12 CFU/ml) produces enzymes that enhance the use of biodegradable polymers for CDDS.
- These polymers shield the drug from the stomach and small intestine and deliver it to the colon, where they undergo assimilation or degradation.
4. pH and Bacterial Enzyme-Dependent Colonic DDS (CODES System)
- The CODES system is a unique CDDS technology that avoids problems associated with pH or time-dependent systems.
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Description
This quiz covers the design and functionality of pH-dependent colonic drug delivery systems, including the use of enteric materials and acid-soluble polymers. It explores the release of drug substances in the colon and the role of pH-adjusting agents.
