Development of xylan-coated acid-resistant micellar drug carriers for colon-targeted oral delivery

Abstract

Oral delivery of hydrophobic drugs from the stomach through the colon has some requirements: (1) an acid-resistant carrier (2) a colon-specific drug release mechanism; and (3) an enhanced bioavailability. In this study, curcumin-loaded polymeric micelles with a xylan-based composite coating were designed and developed. For this purpose, a new synthesis method was used to precipitate xylan by concurrent chitosan polymerization at different xylan/chitosan ratios using a negatively charged crosslinking agent, TPP. The study was to provide the stability of the coated micellar structures in the stomach (low pH conditions) and their degradation in the colon (a natural environment of bacteria) to release the drug. It was observed that the coating successfully prevented early drug release up to 85%, depending on the fraction of xylan in the coating. The nanocarriers that first passed through the stomach conditions were incubated with a xylanolytic colonic bacterium (Bacteroides ovatus) to determine the bacterium-related release mechanism, which was around 27%. This shows the colon-specific release expectation of coated nanocarriers in the colon environment, with an additional benefit due to the degradation of xylan and an improvement in the colon environment by prebiotic activity.

Graphical Abstract

Keywords:

• Chitosan
• colon-targeted drug delivery
• polymeric micelles
• xylan

Acknowledgments

The scholarship of the 100/2000 Ph.D. program provided to Nuket Zeybek by the Council of Higher Education of Turkey was greatly acknowledged.

Authors’ contributions

Nuket Zeybek: Investigation, Data curation, Writing - original draft, Validation. Hurriyet Polat: Conceptualization, Methodology, Writing - original draft, Supervision. Sukru Gulec: Conceptualization, Methodology. Ali Oguz Buyukkileci: Conceptualization, Methodology, Writing - original draft, Supervision.

Disclosure statement

There are no conflicts to declare.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.