Synthesis Of Poly(polyamidoamine-methacylamide-g-anhydride)gels And Study On Their Controlled Drug Release Behavior

As a bone substitute material, gel of dendritic polyamido-methacrylamide(PAMAM-DB)-co-dimethacrylic sebacic anhytride(MSA) is expected to improve the degradation time and drug delivery deficiencies of polyanhydride.Firstly, in this paper, using ethylenediamine as the initiated core,0.5 G (generation) quternionic ester were successfully synthesized via divergent growth approach, namely an exhaustive Michael addition of amino groups with methylacrylate, followed by amidation of the resulting esters with excess ethylenediamine,1.0G quternionic amine were received.repeat the process of Michael addition and aminolysis reaction,2.0G PAMAM were received. FT-IR,1H-NMR,13C-NMR have been adopted for the characterization of the structure of the product. The detection results confirmed the existence of various kinds of characteristic functional and terminal groups of the as-prepared PAMAM, and the results coincided with its theoretical structure.Secondly, MSA was prepared directly by blending acetic anhydride with methacrylic acid, followed by the addition of sebacylic acid to the product above, white powder was got.FT-IR,1H-NMR have been adopted for the characterization of the structure of the product. The detection results confirmed the existence of various kinds of characteristic functional and terminal groups of the as-prepared MSA, and the results coincided with its theoretical structure.Thirdly,2.0G Polyamidoamine(PAMAM) were methacylated by Methacryloyl chloride and photopolymerized with Methacrylated Sebacic Anhydride(MSA) to obtain degradable gels (PAMAM-DB-g-MSA).Structures of the gels were characterized by FT-IR,the result shows functional and terminal groups of the gels change as the variety of the MSA mass fraction in the gels,which is in accordance with the theory.Lastly,physical and chemical property of the gel was studied, its thermal property and stability were analyzed and discussed by DSC(Differential Scanning Calorimetry).At the same time, in order to study the effects of polyamidoamine double bond (PAMAM-DB):MSA ratio on the polymer degradation behavior, local pH, water uptake, mass loss and surface morphology in the course of degradation were explored.It is found that the gels containing 40-50wt% anhydride were good surface erosion materials. Degradation time and pH of degradable medium range from 45 to 60 days, and from 6.50 to 8.06, respectively.Sample with 50wt% anhydride was choosed as the bead of ofloxacin based on the degradation experiment.The result shows the drug-released time and content of drug could be controlled by varing the mass fraction of MSA.