A biodegradable injectable thermoplastic for localized camptothecin delivery.

Area of Science:

• Polymer Chemistry
• Drug Delivery Systems
• Materials Science

Background:

• Camptothecin is a potent anticancer drug with a short half-life, necessitating improved delivery systems.
• Localized drug depots can enhance drug stability and therapeutic efficacy.
• Biodegradable polymers offer potential for controlled drug release applications.

Purpose of the Study:

• To prepare and characterize a thermoplastic, biodegradable polymer drug depot for camptothecin.
• To investigate the in vitro release kinetics of camptothecin from the polymer depot.
• To assess the stability of camptothecin within the depot system.

Main Methods:

• epsilon-Caprolactone oligomers were synthesized via ring-opening polymerization.
• Polymer thermal transitions and melt viscosity were characterized using DSC and rheometry.
• In vitro camptothecin release was evaluated in PBS buffer.

Main Results:

• Oligomer melt viscosity was tunable by altering the initiator.
• The semi-crystalline polymers exhibited melting points between 37-45°C.
• Camptothecin release followed a diffusion-controlled mechanism, with faster release from lower viscosity polymers.
• Camptothecin retained its active lactone form for up to 16 weeks.

Conclusions:

• A biodegradable polymer depot effectively encapsulates and stabilizes camptothecin.
• The drug release rate is controllable via polymer viscosity.
• This system shows promise for localized, sustained delivery of camptothecin.