Controlled-Release Implant System Formulated Using Biodegradable Hemostatic Gauze (Surgicel～(TM))

Polymer-based sustained release implants are widely used as drug delivery systems for brain tumor and other diseases. However, formulation complexity, loading capacity and encapsulation efficiency of these implants remains a plenty of room for improvement. The present research demonstrates a unique and easily fabricated polymer-based sustained-release implant formulated using biodegradable hemostatic gauze, Surgicel^TM, as the scaffold. Phenol red (PhRed, a dye) and carmustine (BCNU, an anti-tumor drug) were chosen as model drugs. A piece of Surgicel^TM was coated with a drug-loaded poly(lactic-co-glycolic) acid (PLGA) solution, with which both hydrophilic and hydrophobic drugs can easily be loaded at high capacity. For drug release kinetics, since the Surgicel^TM scaffold degrade faster than the PLGA polymer coating, the unique diffusion channels created in the process can be used to regulate drug release mechanism. For hydrophilic PhR, reservoir-type release kinetics was observed with rate linearity improved by a drug-free PLGA top-coating. For hydrophobic BCNU, erosion-based release kinetics was achieved, which was converted to a monolithic diffusion type release mechanism with drug-free PLGA top-coating. Characterization of this formulation using XRD and DSC indicated that BCNU was distributed in the PLGA matrix in amorphous state. Images of scanning electron microscope showed that drug-free PLGA top-coating on Surgicel^TM fibers. This research demonstrates a useful and simple procedure to prepare sustained release implant using biodegradable hemostatic gauze as scaffold.