静电喷雾法制备聚膦腈微球

PREPARATION OF POLYPHOSPHAZENE MICROPARTICLES VIA ELECTROSPRAY

用静电喷雾法制备了粒径窄分布的甘氨酸乙酯-苯丙氨酸乙酯取代聚膦腈的微球.主要探讨了溶剂、溶液浓度、流速、喷射电压及接收距离对微球形貌和粒径的影响.微球的表面形貌与溶剂性质和聚合物溶液浓度密切相关,微球粒径受聚合物溶液流速的影响比较显著,随流速增大粒径呈单调上升趋势.结果显示对于[η]=0.1 dL/g的（甘氨酸乙酯）0.3（苯丙氨酸乙酯）0.7取代聚膦腈,以0.25 g/mL的四氢呋喃溶液进行静电喷雾,可获得粒径分布窄（12μm）且近球形的微粒,其工艺条件可进一步用于载药聚膦腈微球的制备和控制释放研究.

The electrospray technique was used to prepare poly[（ethylglycino）-（phenylalanine ethyl ester） phosphazene] microparticles with very low polydispersity.By replacing the chloroform atoms of polydichloro-phosphazene with alanine ethyl ester and glycine ethyl ester subsequently,poly[（ethylglycino）0.30（phenylalanine ethyl ester）0.70phosphazene]（PGPP） was obtained and electrosprayed.The effects of processing parameters such as solvent,polymer concentration,liquid flow rate,applied voltage and receiving distance on the morphology and size of PGPP particles were investigated systematically.The morphologies of the electrosprayed PGPP microparticles were observed by scanning electron microscope（SEM）,and the particle sizes were analyzed by using a software ImageJ basing on SEM photos.It was found that the morphology of PGPP microparitcles depended on polymeric concentration significantly.As PGPP concentration increased from 0.10 g/mL to 0.30 g/mL,rounder particles could be formed.The particles electrosprayed from PGPP solutions in tetrahydrofuran（THF） were less agglomerated than those obtained from the 1,4-dioxane solution,which was thought as a consequence of the faster de-solvent rate of THF.On the other hand,the parameters including the liquid flow rate,applied voltage and receiving distance mainly influenced the size of microparticle,among which,the effect of liquid flow rate on the particle size was most remarkably.The particle size increased with the increasing flow rate,generally obeying the Scaling law,while it decreased by increasing voltage or distance.Experimental data demonstrated that PGPP microparicles with nearly spherical morphology and a size of 1～2 μm could be produced by electrospraying 0.25 g/mL PGPP/THF solution at the optimized parameters.In result,PGPP microparicles with controllable morphology and size could be obtained by changing the various processing parameters of electrospray,and this technique could be used to fabricate drug-loaded polyphosphazene microparticles for further study on the drug controlled release behaviors,which might have potential applications in inhaled drug delivery systems.