Related Experiment Videos
Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives
Y Yamaguchi1, M Takenaga, A Kitagawa
1School of Medicine, Institute of Medical Science, St. Marianna University, Sugao 2-16-1 Miyamae-ku, Kawasaki-shi, Kanagawa-ken, Japan. yyamaguc@marianna-u.ac.jp
Summary
Controlled release of human insulin from poly(lactic-co-glycolic acid) microspheres was achieved by adding glycerol or water. This method suppresses initial insulin burst, enabling potential use in type I diabetes therapy.
Area of Science:
- Biomaterials Science
- Drug Delivery Systems
- Polymer Chemistry
Background:
- Controlled release of therapeutic proteins like insulin is crucial for managing diabetes.
- Poly(DL-lactic-co-glycolic acid) (PLGA) is a widely used biodegradable polymer for drug delivery.
- Achieving sustained and predictable insulin release from PLGA matrices remains a challenge.
Purpose of the Study:
- To investigate methods for controlling the initial release rate of human insulin from PLGA microspheres.
- To explore the impact of additives on insulin encapsulation and release kinetics.
- To assess the potential of modified PLGA microspheres for basal insulin therapy.
Main Methods:
- PLGA microcapsules were prepared using a solvent evaporation multiple emulsion process.
- Solid-in-oil (S/O) and water/glycerol-in-oil (W/O or G/O) dispersions were utilized.
- In vitro and in vivo release studies were conducted.
- Scanning Electron Microscopy (SEM) was used to observe microcapsule morphology.
- Glass transition temperature of PLGA was measured.
Main Results:
- Dispersing crystalline insulin in dichloromethane (S/O) resulted in surface deposition and rapid initial insulin release.
- Addition of glycerol or water to form W/O or G/O mini-emulsions significantly suppressed initial insulin release.
- SEM revealed that additives altered insulin distribution within PLGA microspheres.
- Glycerol addition lowered PLGA's glass transition temperature, affecting microsphere structure and pore formation upon administration.
- Controlled initial release was observed, preventing premature insulin diffusion.
Conclusions:
- The addition of hydrophilic additives like water or glycerol during PLGA microsphere preparation effectively controls initial insulin release.
- This modification prevents surface deposition of insulin and promotes heterogeneous distribution within the matrix.
- The observed controlled release profile holds promise for developing effective basal insulin delivery systems for type I diabetes management.