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Development and Evaluation of pH-Dependent Micro Beads for Colon Targeting
M S Khan1, B K Sridhar, A Srinatha
1Department of Pharmaceutics, National College of Pharmacy, Shivamogga-577 201, India.
Indian Journal of Pharmaceutical Sciences
|June 29, 2010
Summary
Alginate and chitosan hydrogel beads were developed for colon-targeted drug delivery. A 20% weight gain coating effectively protected theophylline from stomach acid, ensuring release in the colon.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
Background:
- Colon targeted drug delivery aims to improve therapeutic efficacy and reduce side effects.
- Alginate and chitosan are biocompatible polymers with pH-sensitive properties suitable for drug delivery.
Purpose of the Study:
- To develop and evaluate alginate-chitosan hydrogel beads for colon-specific delivery of theophylline.
- To assess the impact of enteric coating on drug release characteristics.
Main Methods:
- Multiparticulate beads of alginate and chitosan were prepared using ionotropic gelation.
- Enteric coating was applied using Eudragit S100.
- Formulations were characterized for particle size, encapsulation efficiency, swellability, and in vitro drug release.
Main Results:
- In vitro drug release was dependent on coating weight and pH of the dissolution media.
- Drug release mechanism involved swelling and erosion of the hydrogel beads.
- A 20% weight gain coating provided adequate gastroresistance for targeted colonic release.
Conclusions:
- Alginate-chitosan beads with Eudragit S100 coating are effective for colon-targeted theophylline delivery.
- Optimized coating ensures drug release in the higher pH environment of the colon.