Controlled release of macromolecules from a degradable polyanhydride matrix

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Polymeric matrices are crucial for controlled release of macromolecules, including proteins and polymer-drug conjugates, for targeted drug delivery applications.
• Degradable polyanhydride matrices offer potential for sustained release of therapeutic agents.

Purpose of the Study:

• To investigate the controlled release of macromolecules from degradable polyanhydride matrices.
• To characterize the polymer matrix's physical and chemical changes during macromolecule release.
• To determine the influence of particle size on the release kinetics of tracers.

Main Methods:

• Dispersing solid particles (fluorescein, fluorescently-labeled dextran) in polyanhydride matrices (fatty acid dimer/sebacic acid copolymer).
• Measuring macromolecule release into buffered saline.
• Monitoring polymer changes using infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy.

Main Results:

• Significant polymer hydrolysis occurred within the first day, yet matrices remained intact.
• Micron-sized pores formed during hydrolysis and erosion, facilitating water penetration and tracer diffusion.
• Tracer release rates were dependent on particle size, with smaller particles showing faster release.

Conclusions:

• Degradable polyanhydride matrices can provide sustained release of macromolecules over several days.
• The pore formation mechanism allows for controlled diffusion of tracers.
• Macromolecule release kinetics can be modulated by controlling the size of dispersed particles within the matrix, offering a tunable drug delivery approach.