[Extractible properties of PDLLA under different extraction conditions]

This assay was made to investigate the extractible properties of PDLLA under different extraction conditions. The ratio of test sample to extraction medium was 0.2 g to 1 ml. The distilled water, artificial saliva, Eagle's MEM and hexane were selected respectively as the extraction medium. The samples were extracted under 37 degrees C 24 h, 72 h, 1 w, 2 w and 3 w; 50 degrees C 72 h; 70 degrees C 24 h and 72 h; 121 degrees C 1 h. By use of gas chromatography, the ethyl alcohol, xylene and ethyl acetate content were measured. The results showed the ethyl alcohol content < 1.998 ug/ml, xylene contents was < 53.39 ug/ml and ethyl acetate content < 3.647 ug/m of PDLLA in distilled water, artificial saliva and Eagle's MEM under the condition of 37 degrees C from 24 h to 3 w. The ethyl alcohol content and xylene content in hexane were higher than those in the other three aqueous solutions. When the extracted temperature was increased, the contents of above three components were kept at the original level. There was almost no difference in the extractible properties of PDLLA among distilled water, artificial saliva and Eagle's MEM. The results did not change even if the extraction time and temperature were increased. It is a new concept to evaluate the safety of biomaterials by combining chemical and biological extraction tests, which will be significance in narrowing the gap between physical-chemical tests and biological tests for medical devices.