Biodegradable Anti-adhesion Composite Membranes With Steady PH Value

Adhesion is abnormal attachment between connective tissue band and surrounding tissue or organs. Also adhesion development is a major cause result in postoperative morbidity.In this paper, the polylactic acid / chitosan composite membrane used for the prevention of adhesion after operation was studied. Because the sensibility of nerves in nasal cavity, adhesions often bring great suffering to patients. Polylactic acid is of excellent biocompatibility and biodegradability. As a natural polysaccharide, chitosan is also of biodegradable and good biocompatibility, at the same time, it is of unique biological activity, such as hemostasis and antibacterial. It is an important role in the prevention of adhesions. But polylactic acid is an acidic polymer and do not be dissolved in polar solvents. Chitosan is an alkaline polymer, it can be dissolved in weak acid solution while not be dissolved in non-polar solvent.In addition, after degradation, the product of polylactic are acidic substances, which easily leading to non-infectious inflammation. In this paper, a composite membrane with steady pH value during biodegradation was made, which is of good flexibility and uniform blend.The solvent evaporation method was adopted based on summarizing a deal of methods to prepare polylactide/chitosan composite membrane. According to the composition design of polylactide and chitosan, the chitosan's mass percentage in the whole membrane, and there was a pH-detection experiment in vitro based on uniform membrane. The experimental shows that a good character membrane can be prepared by solvent evaporation method. The solutes were polylactide with molecular weight 450,000 and chitosan with molecular weight 38,000 , the solvent was acetone, chitosan's mass percentage in the whole membrane was 1%.A certain degree of flexibility is required for an anti-adhesive membrane.The experimental shows that chitosan's mass percentage in the whole membrane was about 1.25%, when it not only ensure the pH close to nuetral, but not undermine its mechanical properties; Glyceol was added to the film will help to improve the flexibility; With increasing chitosan's mass percentage in the whole membrane, adding contour glycerol(0.05ml), elongation of the composite membrane increased at first and then decreased; While the chitosan's mass percentage in the whole membrane is 0.75%, elongation of the composite membrane reached the highest.