Controlled-release implant system formulated using biodegradable hemostatic gauze as scaffold

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Biodegradable hemostatic gauze offers a promising scaffold for drug delivery systems.
• Poly(lactic-co-glycolic) acid (PLGA) is a well-established biodegradable polymer for controlled release applications.
• Achieving sustained and predictable drug release remains a challenge in implantable devices.

Purpose of the Study:

• To formulate a polymer-based sustained-release implant using biodegradable hemostatic gauze.
• To investigate the drug release kinetics of hydrophilic and hydrophobic model drugs from the implant.
• To evaluate the influence of scaffold degradation and polymer coating on drug release.

Main Methods:

• Coating commercial Surgicel gauze with poly(lactic-co-glycolic) acid (PLGA) loaded with model drugs (phenol red and carmustine).
• Implementing a drug-free PLGA over-layer to achieve zero-order release kinetics.
• Incubating implants in PBS buffer at 37°C and monitoring drug release over time.
• Analyzing scaffold degradation, drug distribution (XRD, DSC), and polymer coating morphology (SEM).

Main Results:

• A nearly zero-order release profile was achieved for both hydrophilic and hydrophobic drugs over 12-14 days.
• Drug release rate was independent of PLGA polymer type (lactide/glycolide ratio).
• The hydrophilic Surgicel scaffold degraded within 3 days, suggesting drug release via scaffold-derived diffusion channels.
• Carmustine (BCNU) was found in an amorphous state within the PLGA matrix.

Conclusions:

• A novel sustained-release implant was successfully formulated using PLGA-coated biodegradable gauze.
• The implant demonstrates potential for controlled, long-term release of various drugs.
• Scaffold degradation plays a significant role in the drug release mechanism, independent of polymer coating thickness.