Hyaluronan/B12-chitosan polyelectrolyte complex for oral colistin administration

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Pharmaceutical Sciences

Background:

• Polyelectrolyte complexes (PECs) from hyaluronic acid (HA) and chitosan (CS) show potential for delivering antimicrobial agents like colistin (CT).
• Improving intestinal permeability via ligand modification of CS is key for oral bioavailability of PECs.

Purpose of the Study:

• To develop CT-loaded PECs using HA and cyanocobalamin (vitamin B12)-modified CS.
• To evaluate the physicochemical properties, drug release, antimicrobial activity, and permeability of the developed PECs for oral delivery.

Main Methods:

• Preparation of PECs using HA and vitamin B12-modified CS.
• Characterization of PECs size, zeta potential, encapsulation efficiency, and drug content.
• In vitro drug release studies and antimicrobial activity assays against Pseudomonas aeruginosa.
• Measurement of apparent permeability coefficient for CT in PEC formulation.

Main Results:

• CT-loaded PECs exhibited a hydrodynamic size of ~284 nm and positive zeta potential of ~26 mV.
• High encapsulation efficiency (88.2%) and CT content (42.2 μg/mg) were achieved.
• Two-phase drug release observed, with sustained release over 5 hours. Antimicrobial activity was preserved, and permeability coefficient was 2.4 × 10⁻⁶ cm/s.

Conclusions:

• HA- and vitamin B12-modified CS-based PECs offer a simple and effective method for improving the oral delivery of colistin.
• Vitamin B12 modification enhances intestinal targeting and permeability, boosting oral bioavailability.