Studies On Preparation And Properties Of Poly Vinyl Alcohol Based Controlled Release Carrier

The study took poly vinyl alcohol, chitosan, sodium alginate as materials, used solution method to prepare poly vinyl alcohol, poly vinyl alcohol-chitosan and poly vinyl alcohol-sodium alginate controlled release carriers by physical and chemical crosslinking methods, optimized synthetic process conditions, systematically studied the influence factors which effect on swelling ratio and mechanical properties of poly vinyl alcohol based controlled release carriers, and the relation between structure and properties, investigated the bio-degradation of controlled release carriers, studied the process conditions which effect on drug releasing rate of poly vinyl alcohol based controlled release carriers. The main content of this study is:The effect of process conditions of poly vinyl alcohol controlled release carriers, such as concentration of PVA, freeze-thaw cycle times, concentration of glutaraldehyde on swelling ratio, hardness, drug releasing rate was significant. The process conditions of poly vinyl alcohol controlled release carriers were optimized by orthogonal experiment. The result is: concentration of poly vinyl alcohol is 10%, freezing time is 12h, freeze-thaw cycle times is 3. Under these conditions, poly vinyl alcohol controlled release carriers has best drug releasing ratioThe effect of mass ratio of PVA to chitosan and concentration of glutaraldehyde on swelling ratio and hardness of PVA-Chitosan controlled release carriers is significant. The result of orthogonal experiment is: mass ratio of PVA to chitosan is 2:1, the volume of acetic acid is 20mL, the concentration of crosslinking agent glutaraldehyde is 3%, the concentration of formaldehyde is 3%. Under these conditions, the sample of best swelling ratio is prepared. Side-chain of chitosan has amino group. Because amino group protonate easily, PVA-chitosan controlled release carriers own pH sensitivity and temperature sensitivity. PVA-chitosan controlled release microspheres were prepared and systematically studied the effect of process conditions on hardness and drug releasing rate.The preparation conditions of concentration of poly vinyl alcohol, sodium alginate, CaCl₂ were closely related to swelling ratio, hardness and drug releasing rate of PVA-Alg controlled release carriers. The process conditions of PVA-Alg were optimized by orthogonal experiment. The result show that concentration of poly vinyl alcohol is 3.5%, concentration of sodium alginate is 2.25%, concentration of CaCl₂ is 20.00%. The sample has best drug releasing ratio.The experiment of poly vinyl alcohol based controlled release carriers showed that poly vinyl alcohol, PVA-chitosan, PVA-Alg controlled release carriers have good bio-degradation.