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Enteric-coated epichlorohydrin crosslinked dextran microspheres for site-specific delivery to colon
Gopal Rai1, Awesh K Yadav1, Narendra K Jain1
1a Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences , Dr. Hari Singh Gour University , Sagar , India.
Drug Development and Industrial Pharmacy
|May 27, 2015
Summary
Enteric-coated dextran microspheres successfully delivered 5-Fluorouracil (5-FU) to the colon. The formulation demonstrated controlled drug release, enhanced by colonic enzymes, indicating targeted delivery potential.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery Systems
- Biomaterials Science
Background:
- Colon drug delivery faces challenges with premature drug release in the upper gastrointestinal tract.
- Dextran microspheres offer potential for oral drug delivery due to their biocompatibility.
- Developing targeted colon delivery systems is crucial for treating colonic diseases effectively.
Purpose of the Study:
- To develop and characterize enteric-coated dextran microspheres for targeted colon delivery of 5-Fluorouracil (5-FU).
- To evaluate the drug release profile and enzymatic degradation of the microspheres in simulated physiological conditions.
- To assess the pharmacokinetic and biodistribution of the optimized formulation in vivo.
Main Methods:
- Microspheres were prepared using an emulsification-crosslinking method with varying dextran molecular weights and crosslinking agent volumes.
- Enteric coating was achieved using an oil-in-oil solvent evaporation technique with Eudragit polymers.
- Drug release studies were conducted in simulated gastric and intestinal fluids, with and without dextranase and rat caecal contents. Pharmacokinetic and organ distribution studies were performed in albino rats.
Main Results:
- Dextran microspheres exhibited high entrapment efficiencies (77-87%) and suitable particle sizes (10-25 µm).
- Uncoated microspheres showed rapid drug release, while enteric-coated microspheres demonstrated minimal release at low pH and controlled release at higher pH.
- Significant drug release was observed in the presence of dextranase and caecal contents, confirming susceptibility to colonic enzymes.
Conclusions:
- Enteric-coated dextran microspheres are a promising system for targeted colon delivery of 5-FU.
- The formulation provides protection in the upper GI tract and controlled release in the colon.
- In vivo studies support the potential of these microspheres for effective colon targeting.
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