Ionic agarose derivatives as polyelectrolytic additives for drug release

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Polysaccharides are widely utilized as hydrogels in biomedical applications for drug release owing to their biocompatibility and inherent properties.
• Agarose, a natural polysaccharide, offers thermoreversible gelling capabilities, making it a promising candidate for advanced drug delivery systems.
• Developing functionalized polysaccharides with tunable properties is crucial for enhancing drug release profiles and therapeutic efficacy.

Purpose of the Study:

• To synthesize and characterize novel anionic and cationic ionic agarose derivatives.
• To investigate the application of these ionic agarose derivatives in composite scaffolds and layer-by-layer coatings for sustained drug release.
• To evaluate the drug release kinetics using established and novel modeling approaches.

Main Methods:

• Homogeneous derivatization of agarose in ionic liquid to produce anionic (agarose sulfates) and cationic (ammonium-bearing agarose carbamates) derivatives with controlled degrees of substitution.
• Synthesis of agarose sulfates in a one-step process and cationic agarose carbamates via agarose phenylcarbonates.
• Preparation of composite scaffolds with hydroxyapatite and layer-by-layer coated alginate microbeads using oppositely charged ionic agarose derivatives.
• Incorporation and sustained release studies of adenosine triphosphate, suramin, methylene blue, and A740003 over 14 days.
• Analysis of release curves using conventional models and two novel Langmuir-like models, assessing performance with Akaike's Information Criterion.

Main Results:

• Successfully synthesized anionic and cationic ionic agarose derivatives with tunable degrees of substitution, retaining partial thermoreversible gelling behavior.
• Ionic agarose derivatives incorporated into composite scaffolds and alginate microbeads significantly reduced burst release and sustained the release of multiple model drugs over 14 days.
• Novel Langmuir-like models provided superior fitting and additional insights into the drug release mechanisms compared to commonly used models, as indicated by Akaike's Information Criterion.

Conclusions:

• Ionic agarose derivatives represent a versatile platform for developing advanced hydrogel-based drug delivery systems.
• The tunable nature and polyelectrolyte characteristics of these derivatives enable precise control over drug release kinetics, enhancing therapeutic outcomes.
• The application of novel kinetic models is beneficial for a deeper understanding of drug release mechanisms from complex biomaterials.