A new type of biodegradable polyesteramide P(LA/AU) based on lactic acid and aminoundecanoic acid was synthesized by the melt polycondensation method. The copolymers obtained were characterized by FTIR. 1H-NMR. DSC. and XRD。 The in vitro degradation behavior of the copolymers was strdied using weighing. H-NMR, FTIR. DSC, and SEM. With the increase in aminoundecanoic acid units, the milting temperature and units, the melting temperature and crystallinity increased, but the water absorption and degradation rate decreased accordingly. During degradation in vitro, the ester mority decreased due to ester cleavage along the macromolecular main chain. As degradation proceeded, the melting temperature and crystallinity increased at first, then started to decrease because the crystalline phase was destroyed.

In this work, a new kind of aliphatic polyesteramide (PEA) copolymer based on €-caprolactone and 6-aminocaproic acid was synthesized by the melt polycondensation method. Biodegradable PEA fibers were processed by the meltspinning method. 1H-NMR, FTIR, SEM, and tensile testing were used to characterize the degradation of PEA fibers in concentrated alkaline solution. The PEA fiber undergoes surface erosion in such concentrated alkaline solutions.

Biodegradable polyesteramide copolymer P (CL/AU) based on €-caprolactone and 11-aminoundecanoic acid was synthesized by the melt polycondensation method. Polyesteramide (PEA) microspheres were prepared by a simple O/W emulsion solvent evaporation method. The effects of variations in preparation parameters (such as emulsifier concentration, polymer concentration, polymer solution adding rate, stirring rate, and whether vacuum was applied) were studied in detail. The obtained microsphere morphologies were observed using an optical microscope and via scanning electron microscopy (SEM). The particle size distribution was determined using a Malvern laser particle sizer. When the PEA microspheres were incubated in PBS saline, the particle size increased at first, and then decreased after a longer time period; the theory that this behavior was due to degradation of the microspheres was confirmed by SEM.

Factors influencing the in vitro release of bovine serum albumin (BSA) from poly(butylcyanoacrylate) (PBCA) nanocapsules, such as the pH value, BSA loading, the polymeric nanocapsule walls and protein molecular weight, were investigated in detail. The BSA release rate was affected by the degradation rate of the polymeric wall and protein loading. For low molecular weight proteins, the initial burst release was faster than that of high molecular weigh proteins and got to equilibrium quickly. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis results showed that BSA encapsulated within PBCA nanocapsules did not suffer covalent aggregation or fragmentation during the initial days of in vitro incubation. For nanocapsules prepared by interfacial polymerization in waterinoil microemulsions, these findings were useful as a foundation for the development of nanocapsules with desired properties.