Insulin-albumin microbeads: an implantable, biodegradable system

Area of Science:

• Biomaterials Science
• Endocrinology
• Drug Delivery Systems

Background:

• Diabetes mellitus requires consistent insulin management.
• Current insulin delivery methods face challenges with sustained release and patient compliance.
• Biodegradable implantable systems offer a potential solution for long-term therapeutic delivery.

Purpose of the Study:

• To evaluate the feasibility of an implantable, biodegradable insulin delivery system using insulin-albumin microbeads.
• To assess the in-vivo performance and biodegradation of these microbeads in a diabetic rat model.

Main Methods:

• Insulin-albumin microbeads (50-1,000 microns) were prepared and cross-linked with glutaraldehyde.
• Microbeads were subcutaneously implanted into diabetic rats.
• Blood insulin levels, animal weight, and implant biodegradation were monitored over time.
• Histological examination identified fibrous capsule formation around implants.

Main Results:

• Sustained elevated blood-insulin levels (10-67 microU/ml) were observed for over two months post-implantation.
• Complete in-vivo biodegradation of microbeads occurred in over five months.
• Implanted diabetic rats showed weight gain, unlike untreated controls.
• Fibrous capsules formed around implants, potentially retarding insulin release.

Conclusions:

• Cross-linked serum albumin microbeads demonstrate potential for long-term in-vivo insulin release.
• The biodegradable nature and flexible implantation options enhance clinical applicability.
• Fibrous capsule formation may modulate the drug release rate, suggesting a tunable delivery system.