Trisacryl gelatin microspheres for therapeutic embolization, I: development and in vitro evaluation.

PURPOSE To develop a precisely calibrated, perfectly spherical, stainable, soft, and implantable but nonresorbable particulate embolization material. METHODS Calibrated particles with a trisacryl gelatin polymer core and hydrophilic surface characteristics were obtained by reversed emulsion synthesis followed by application of a wet-sieving technique. Particles were suspended in saline, bottled, and sterilized. Quality control included analysis of particle diameters before and after sieving and of suspension sterility and apyrogenicity. Particles were subsequently tested to ascertain their compatibility with commercially available microcatheters. RESULTS The resulting embolization material consisted of spherical, stainable microspheres of medical grade with diameters ranging from 130 microns to 1200 microns. Sieving the suspension produced particle groups of homogeneous size (accuracy, +/- 20-100 microns). At injection, the particles showed no tendency to build aggregates or to obstruct the microcatheters. CONCLUSION Precisely calibrated and easy-to-use microspheres were obtained that satisfied the biomedical requirements for implantation as an embolization material.