Preparation and application of cross-linked PVA microspheres with narrow particle size distribution by suspension polymerization using uniform porous tube

PVA microspheres have high strength and plenty of hydroxyl groups, which has obvious advantages in a hydrophilic environment. However, the preparation of uniform larger size PVA microspheres with a diameter bigger than 100 μm is still extremely tough. Membrane emulsification is an excellent method to obtain a monodisperse microsphere, but the diameter is generally several microns to tens of microns. Inspired by the membrane emulsification method, in order to get over 100 μm microspheres, on titanium tube uniform micropores were produced by laser drilling. Uniform monomer droplets with vinyl acetate and cross-link agent 1,4-butanediol divinyl ether (BDVE) were all the time obtained by a simple device applying the tube as a membrane. After polymerization, cross-linked PVAc microspheres underwent alcoholysis. Cross-linked PVA microspheres ultimately were obtained. PVA microspheres' sizes varied from 120 μm to 800 μm with a maximum coefficient of variation of less than 13% were prepared by changing different pore size tubes. Cross-linked PVA microspheres have a good spheroidal shape, solvent resistance and good strength. Through the amination reaction, some hydroxyl groups were connected with amino groups, which was more conducive to the loading of drug molecules such as indomethacin.