Novel iron-polysaccharide multilayered microcapsules for controlled insulin release

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Nanotechnology

Background:

• Iron-polysaccharide complexes are established treatments for iron-deficiency anemia.
• Developing effective controlled-release systems for proteins like insulin is crucial due to their short half-lives.

Purpose of the Study:

• To create novel insulin-loaded microcapsules using layer-by-layer deposition of iron(III) and dextran sulfate.
• To evaluate the efficacy of these microcapsules as a controlled release system for insulin, focusing on glucose tolerance and hypoglycemic effects.

Main Methods:

• Insulin microparticles were coated using layer-by-layer deposition of iron(III) and dextran sulfate, forming stable (Fe(3+)/DS)(n) multilayers.
• Protamine was used as an outermost layer to enhance nuclear delivery and prolong drug release.
• Encapsulation efficiency, drug loading content, and in vitro release profiles were analyzed.
• In vivo studies assessed glucose tolerance and hypoglycemic effects compared to free insulin and microcapsules with different outer layers.

Main Results:

• Successfully fabricated hollow microcapsules with high insulin encapsulation efficiency (70.56%) and drug loading content (46.15%).
• Increased number of deposited bilayers extended insulin release time and enhanced the hypoglycemic effect.
• Insulin-loaded microcapsules significantly improved glucose tolerance for up to 12 hours.
• Protamine-coated microcapsules demonstrated a more prolonged and stable glucose-lowering profile over 6 hours compared to Fe(3+)-coated microcapsules.

Conclusions:

• The developed iron-polysaccharide-based microcapsules represent a promising controlled release delivery system for insulin.
• This approach is potentially applicable to other protein-based therapeutics with short half-lives.
• The layer-by-layer assembly technique offers tunable properties for optimizing drug release kinetics and therapeutic efficacy.