David P. Vanderbilt

Biodegradable Polyamides Based on 4,4′-Spirobibutyrolactone

This paper describes the synthesis, structure, and some properties of a new family of biodegradable poly(amides) based on 4,4′-spirobibutyrolactone (SBBL). The polymers were synthesized using melt polymerization techniques similar to those used to prepare nylon 6,6. Both homopolymers (SBBL + diamine) and block copolymers (SBBL + diamine + nylon salt) were prepared. The homopolymer and copolymer backbones contain lactam and spirolactam groups in addition to the expected secondary amide groups. Homopolymers were found to degrade completely in neutral phosphate buffer, while the block copolymers degraded only partially in vitro and in vivo. The copolymers evoked only a mild tissue response when implanted subcutaneously in rabbits. Other properties of this unusual family of polymers are discussed.