Research of Synthesis and Properties of Polyurethane Mrcrosphere Modified with Polylactic Acid
|School||Southwest Jiaotong University|
|Course||Biochemistry and Molecular Biology|
|Keywords||Microspheres Polyurethane Diclofenac Polyethylene glycol Polylactic acid|
Orthogonal test method to optimize the synthesis conditions of the PLA, and the synthesis of PLA performance testing. IR spectra show ,1210-1160 cm-1 at the COC asymmetric stretching vibration, 1100 cm-1 COC in symmetric stretching vibration absorption peak of 1760 cm-1 at the C = O stretching vibration absorption peak, the synthetic product PLA; measured by GPC PLA samples, molecular weight of about 420, the molecular weight distribution is concentrated; Synthesis of PLA optimal conditions: the amount of lactic acid for 30 ml, the amount of catalyst is 0.5% of the amount of lactic acid, the reaction temperature as 130-135 ° C. The reaction time is an important factor to influence the size of the PLA molecular weight of different molecular weight PLA can be prepared by controlling the time. PU microspheres synthesized using orthogonal analysis to determine the optimal conditions: -OH/-NCO = 1/4, the diisocyanate IPDI, solids content for the 40% CaCl2 solution of a concentration of 8%; infrared spectroscopy showed that the synthesis of the formation of hydrogen bonds in the polyurethane; microspheres calcification crosslinking time is advised for 5-6h. By self-emulsification method using PEG, PLA, IPDI, DMPA, TEA was prepared nano-polyurethane emulsion, after calcium cross-linked to form PU microspheres. Emulsion particle size gradually decreases with increasing molecular weight of PEG, and then decreased with the reduction of the PEG content firstly increases; synthetic hydrophilic PU increase with increasing molecular weight of PEG, the degree of swelling increases, micro- ball degradation rate increases with increasing the molecular weight of the PEG, PEG content increases gradually reduce the rate of degradation; polyurethane synthesized predominantly amorphous structure, and with the increase in the PEG molecular weight and the content of PU amorphous reduce the proportion of . In addition, the emulsion particle diameter is increased with the increase of PLA molecular weight and the content of; synthetic hydrophobic PU increase with increasing the molecular weight of the PLA, the swelling ratio decreases; degradation rate of the microspheres with the PLA molecular weight and the increase of the content. ; With the the PLA increase in molecular weight amorphous structure increase, decrease with increasing the content of PLA amorphous structure. Morphological observation showed that the smooth surface of the microspheres, spherical rounded surface and internal pore structure, present inside the cavity, and PLA-modified PU microspheres have good blood compatibility and cell compatibility, suitable for pharmaceutical carrier material; DS as a model drug, the microspheres prepared DS-PU drug loading, infrared spectroscopy showed that, DS has been wrapped into the PU microspheres; first increases with increasing drug concentration, drug encapsulation rate was and then decreases, the amount of drug gradually increase the final stabilized in vitro release studies have shown that PU microspheres with sustained release, can delay the release of the DS, thus prolonging the half-life of the DS.