Studies On The Synthesis And Properties Of BiodegradablePoly (Amide-anhydrides) And Poly (ester-anhydrides)

In recent years, biodegradable polymeric materials have been used for drug delivery, bone and cartilage repairing, cell issue engineering application. Compared to non-biodegradable polymers, they have favorable advantages. That is, they do not need to be taken out and can degrade into small molecules in body. Biodegradable polymers are the most potential materials for biomedical applications. In this paper, recent developments of biopolymers were reviewed. Novel biodegradable polymers-poly anhydrides have been developed since 1980s' by the group of Langer. These materials are highly biocompatible, demonstrated by tissue response and toxicological study. In addition, they show surface-eroding behavior, thus provide a sustained release rate over a long period of time, and the rate is adjustable. So these materials are very promising in biomedical applications. This paper presented an outline of recent researches and clinical applications of this kind of polymers.Amide containing polyanhydrides based on natural amino acids are novel materials which have lots of superior properties. One advantage is that the alternate amide groups in the main chains slow down the rate of degradation. Another important advantage is that the physical and mechanical properties are raised as the result of the incorporation of hydrogen bonds which reinforce the polymer by intermolecular attractive forces. In this paper we synthesized N,N'-bis(L-alanine)sebacoylamide(BASM) and PBASM, a novel amide-containing polyanhydride. BASM was then copolymerized with CPH which increased the hydrophobic property and slowed down the release rate. Then the blends of copolymers and PLA with different weight ratios were prepared. The thermal properties and in vitro degradation(PBS, pH=7.4, 37C) of these polymers were studied in this research.In order to prepare monomers of this kind of poly(amide-anhydrides), N-Carboxymeth yl-succinamic acid, N-(1-Carboxy-ethyl)- succinamic acid, 4-(Carboxymethyl- carbamo- yl)- butyric acid, 4-(1-Carboxy-ethyl carbamoyl)-butyric acid, 5 -(Carboxym- ethylcarb- amoyl)- pentanoic acid, 5-(1-Carboxy-ethylcarb amoyl)-pentanoic acid were synthesized by the react of adipic anhydride with glycine and L-alanine respectively. The intermediates and objective products were identified by spectrum of IR, 1HNMR.Recently, many polymeric and conjugated prodrugs have been developed which prolong the blood concentration of the drug as compared to the free drug given alone.This phenomenon is indicative of the prodrug's ability to release the drug in a controlled manner and reduced the site effects which may be incurred if the drug is released immediately. In this paper, o-Carboxy phenyl adipic monoester was synthesized for the first time from adipic anhydride and salicylic acid, from which the related polymers were prepared. Additionally, several factors which affected the molecular weight had also been studied, such as vacuum, temperature and so on. The degradation under PBS with different pH was also estimated.