The Studys On The Preparation And Property Of Sodium Alginate/Polyurethane Complex Hydrogel Microsphere

This paper studied the synthesis and performance of polyurethane microcapsules.Alginate gel microspheres were prepared,and its performance was explored.Polyurethane and sodium alginate was blended to get a new type of gel microspheres and study the performance of its loading drugs.Polyurethane(PU) water solutions were synthesized and PU microcapsules were synthesized with the coacervation phase separation method.The results show that the optimal conditions of synthesizing the spherical PU microcapsules are as follows:the mole ratio of IPDI and PEG(200) is 6:2,the grosses of monomers are 45%,the concentrations of CaCl₂ are more than 4%,Chain-extension temperature of 50℃,the time for chain-extension 3.0h,prepolymer mixing speed of reaction of 500～600r/min,stirring speed chain reaction extended to 500 550 r/min,stirring speed and reaction to 650 r/min or so.The surfaces are provided with porosity,the diameter of the PU microcapsules is 3ram or so,the diameter of cavities in PU microcapsules is 2mm or so.Sodium alginate gel microspheres were prepared by condensed phase separation.The experimental results showed that,when the concentration of sodium alginate solution was 3%and CaCl₂ concentration was greater than 1.0%, the best form and strength of sodium alginate gel microspheres could be obtained. Microspheres was non-swelling in hydrochloric acid(pH 1.0) but rapid swelling in pH 6.8 and 7.4 phosphate buffer solution.And microspheres in pH 7.4 phosphate buffer solution was better swelling than in pH 6.8 phosphate buffer solution.Through the blends of sodium alginate solution and polyurethane solution,the composite gel prepared microspheres was prepared by condensed phase separation. The experimental results showed that when the percentage content of polyurethane is 10%,30%,50%,microspheres could be prepared well.With the increase of polyurethane in the blend solution,the moisture content of composite microspheres was less and less.The composite microspheres was non-swelling in hydrochloric acid(pH 1.0) but rapid swelling in phosphate buffer solution(pH 6.8 and 7.4).The composite microspheres in which the percentage content of polyurethane was 30%,50%swelled less slowly than the sodium alginate microspheres in pH 6.8 and 7.4 phosphate buffer solution,the intensity was also better than the sodium alginate microspheres,the composite microspheres containing 50%polyurethane was slowest swelling,of which the intensity was the best.The release of drug properties of the SA/PU complex hydrogel microspheres was proded into.Experimental results showed that the release speed of composite microspheres was faster than that of sodium alginate gel microspheres.SA/PU complex hydrogel microspheres showed a good performance of drug-loading efficiency and a good effect on the drug sustained-release,is expected to have a further application on drug delivery.