Multifunctional Composite Microcapsules for Oral Delivery of Insulin

Area of Science:

• Biomaterials Science
• Nanotechnology
• Pharmacology

Background:

• Oral insulin delivery faces challenges including low encapsulation efficiency and premature degradation.
• Existing methods struggle with targeted delivery and controlled release, limiting therapeutic efficacy.
• Developing effective oral insulin formulations is crucial for improving diabetes management.

Purpose of the Study:

• To design and develop multifunctional composite microcapsules for enhanced oral insulin delivery.
• To improve insulin encapsulation efficiency and protect it from degradation.
• To achieve targeted gastrointestinal delivery and control insulin release, thereby enhancing bioavailability.

Main Methods:

• Insulin was complexed with sodium deoxycholate via hydrophobic ion pairing to form an insulin-sodium deoxycholate complex.
• The complex was encapsulated into poly(lactide-co-glycolide) (PLGA) nanoparticles (mean size 168 nm, zeta potential -29.2 mV) using emulsion solvent diffusion.
• Multifunctional microcapsules were prepared by encapsulating PLGA nanoparticles into pH-sensitive hydroxypropyl methyl cellulose phthalate (HP55) using organic spray-drying for enteric targeting.

Main Results:

• The encapsulation efficiency of the insulin-sodium deoxycholate complex reached 94.2%.
• In vitro studies demonstrated a pH-dependent insulin release profile, indicating controlled release.
• Administration of the composite microcapsules in diabetic fasted rats showed a significant enhancement in relative insulin bioavailability.

Conclusions:

• The developed multifunctional composite microcapsules effectively enhance insulin encapsulation efficiency and protect insulin from degradation.
• The formulation exhibits controlled, pH-dependent insulin release, suitable for targeted gastrointestinal delivery.
• This oral insulin delivery system demonstrates significant potential as an effective therapeutic candidate for diabetes management.