Preparation And Characterization Of Poly(γ-glutamic Acid)/Polyvinyl Alcohol Hydrogels

y-Polyglutamic acid(y-PGA) is a pH-sensitive, non-toxic, biodegradable biopolymeric product and it can be applied in medicine, food and others fields. In order to reduce its cost, using the solid fermentation of soybean to produce y-PGA; in order to widen its application field, y-PGA was reacted with polyvinyl alcohol (PVA) to form hydrogel without any chemical treatment. In addition, the drug releasing property of this system were determined. The obtained results are as follows:Using the solid fermentation of bacillus natto to produce y-PGA. A Box-Behnken design was used to evaluate the extraction effects of the three related factors. The optimal addition was that the inoculum size was 1.4mL, the concentration of sodium chloride was 7.8mg/mL, potassium hydrogen phosphate was 0.003mmol/g and y-PGA was obtain 6.43g/kg.pH-sensitive anionic hydrogels composed of poly(vinyl alcohol) (PVA) and poly(y-glutamic acid) (y-PGA) were prepared by freeze-thawing method and the freeze drying method. To discusse the swelling ratio in fifferent pH buffer solution., swelling kinetics, water retention and swelling-deswelling reversibilityof the hydrogels. The biodegradation rate, thermal stability and the mechanical properties of the stimuli-sensitive hydrogels were studied.The swelling kinetic of y-PGA/PVA hydrogels were studied. The results indicated that at different pH conditions, the transport mechanism of all hydrogels is non-Fickian transport; The diffusion coefficient values of all hydrogels increase with the increase in the swelling rates at the same pH conditions.A preliminary study of the PGA/PVA hydrogels as the drug delivery system for the model drug 5-FU. It was showed that at pH7.4 the release rate is faster. And at pH7.4 and pH1.2 the release rate decrease with increasing y-PGA content.