Poly(anhydride‐ester) fibers: Role of copolymer composition on hydrolytic degradation and mechanical properties

Abstract

Poly(anhydride-esters), based on carboxyphenoxydecanoate (CPD), are biocompatible polymers that hydrolytically degrade. The mechanical properties of the poly(anhydride-esters) can be altered by copolymerization with para-carboxyphenoxyhexane (pCPH). Mechanical properties of three CPD:pCPH compositions (30:70, 40:60, and 50:50) are reported as a function of hydrolytic degradation. The mechanical characteristics evaluated were tensile modulus at 1% strain (E(1%)), tensile strength (sigma(B)), ultimate elongation (epsilon(B)), and toughness (E(r)). The 30:70 CPD:pCPH fibers maintained higher values for tensile modulus at all time points than the two other fiber compositions. In addition, the 30:70 CPD:pCPH fibers maintained lower values for both tensile strength and toughness than the two other fiber compositions. These phenomena resulted from the brittle nature of pCPH, the major component of the 30:70 CPD:pCPH fibers; increasing the pCPH concentration in the polymer lowers both tensile strength and toughness of the polymer by decreasing ductility. With increasing amounts of pCPH, the hydrolytic degradation occurred more slowly, as reflected in the copolymers' improved ability to retain their mechanical properties. Therefore, copolymerization is useful for controlling the mechanical properties of the fibers as well as the polymer degradation rate, which ultimately determines the rate at which physically or chemically encapsulated drugs can be released.

Polyactives: controlled and sustained bioactive release via hydrolytic degradation

“…Chemical copolymerization of SA-based (sebacic) PAE and para-carboxyphenoxyhexane (pCPH) repeat units (Figure 13) yielded a copolymer with significantly higher T g compared to the SA-based homopolymer (33 °C versus 27 °C), which greatly enhanced its processability at room temperature. 92 In addition, different ratios between the SA-based (sebacic) PAE and pCPH units resulted in different copolymer properties: higher pCPH percentage yielded copolymers with lower tensile strength, lower Young’s modulus, lower ultimate elongation and lower toughness as the pCPH unit is more brittle than the SA-based unit. 92 Copolymers with more pCPH units were also more hydrophobic, which led to a slower hydrolytic degradation rate and, thus, less significant changes in polymer properties when incubated in PBS.…”

“…92 In addition, different ratios between the SA-based (sebacic) PAE and pCPH units resulted in different copolymer properties: higher pCPH percentage yielded copolymers with lower tensile strength, lower Young’s modulus, lower ultimate elongation and lower toughness as the pCPH unit is more brittle than the SA-based unit. 92 Copolymers with more pCPH units were also more hydrophobic, which led to a slower hydrolytic degradation rate and, thus, less significant changes in polymer properties when incubated in PBS. 92 These parameters are important for choosing bioactive-releasing implant materials with stable properties after implantation.…”

Polymeric formulations for drug release prepared by hot melt extrusion: application and characterization

“…HME was used to prepare PolyAspirin TM , which is a fiber composed of a poly(anhydride-ester) synthesized by copolymerization of salicylate monomer, carboxypenoxydecanoate (CPD) and para-carboxyphenoxyhexane (pCPH). In an aqueous environment, PolyAspirin TM undergoes hydrolysis, which results in the formation and release of salicylic acid [51].…”

Salicylic Acid-Based Polymers for Guided Bone Regeneration Using Bone Morphogenetic Protein-2

“…A previous study showed that SAPAE polymer pliability and SA release can be changed by copolymerization of different SAPAE monomers. 60 In this study, PCL was electrospun with the FD-SAPAE or the SD-SAPAE polymer to improve the handling characteristics of the electrospun membrane. Composite membranes containing 60% PCL and 40% SAPAE were found to have optimal handling characteristics, which included sufficient pliability to wrap the femur defect.…”