pH-sensitive and mucoadhesive thiolated Eudragit-coated chitosan microspheres

Area of Science:

• Pharmaceutical Sciences
• Biomaterials Science
• Drug Delivery Systems

Background:

• Oral protein delivery faces challenges due to enzymatic degradation and poor absorption.
• Chitosan microspheres (CMs) offer potential for drug delivery but require modifications for enhanced properties.
• Developing mucoadhesive and pH-sensitive systems is crucial for effective oral drug targeting.

Purpose of the Study:

• To develop an oral protein drug delivery system using Eudragit-cysteine conjugate-coated chitosan microspheres (CMs).
• To impart mucoadhesive and pH-sensitive properties to the chitosan microspheres for enhanced oral delivery.
• To evaluate the drug release characteristics and structural integrity of the model protein drug (bovine serum albumin - BSA).

Main Methods:

• Coating of chitosan microspheres with Eudragit-cysteine conjugate to form thiolated Eudragit-coated CMs (TECMs).
• Loading of bovine serum albumin (BSA) into TECMs and evaluation of its release profile at different pH levels (2.0 and 7.4).
• Assessment of BSA structural integrity using SDS-PAGE and CD spectroscopy.
• Evaluation of mucoadhesive properties using in vitro intestinal mucosa adhesion tests and in vivo gamma camera imaging in rats.

Main Results:

• BSA release from BSA-loaded TECMs was suppressed at pH 2.0 and sustained for hours at pH 7.4.
• The structural integrity of released BSA was confirmed by SDS-PAGE and CD spectroscopy.
• TECMs exhibited significantly higher mucoadhesion compared to CMs and Eudragit-coated CMs (ECMs), confirmed by in vitro and in vivo studies.

Conclusions:

• TECMs demonstrate effective mucoadhesive and pH-sensitive properties suitable for oral drug delivery.
• The developed system successfully protected and controlled the release of the model protein drug, BSA.
• TECMs show significant potential as carriers for oral protein drug delivery systems.