Abstract: Objective：To develop and study the properties of crosslinked polyvinyl alcohol microspheres (PVA-Ms) for embolization. Methods: The PVA-Ms were produced by emulsion chemical crosslinking method. Fourier transform infrared spectroscopy (FT-IR) was used to investigate the special functional groups of PVA-Ms; the morphology and particle size of PVA-Ms were determined by optical microscope; the ratio of water absorption and the swelling ratio were also investigated; the compressibility was examined by texture analyzer. A new device was designed to measure the pressure of PVA-Ms during their delivery through catheter for embolization. Results: The crosslinking reaction of PVA and formaldehyde was proved by FT-IR. The PVA-Ms were round with smooth surface. The average diameter of lyophilized PVA-Ms was 574.2 μm with a range of 80~1 800 μm and of wet PVA-Ms was 602.2 μm with a range of 100~1 900 μm. The average ratio of water absorption was 175% and the swelling ratio was 48.6%. The PVA-Ms were mechanically stable with appropriate elasticity and delivered through the catheter without any difficulty, and the pressure was higher for larger size of microspheres to be delivered. Conclusion: PVA-Ms prepared in this study was supposed to be suitable for clinical embolization according to the physicochemical properties. The study provides a series of methods to evaluate the properties of microspheres systemically for embolization in vitro.

Key words: Embolization, therapeutic, Microspheres, Polyvinyl alcohol, Cross-linking reagents