| abstract |
The invention relates to a process for the preparation of beads comprising a biocompatible hydrophobic polymer, a perfluorocarbon and optionally a metal compound, comprising the steps of: na) adding the perfluorocarbon and optionally the metal compound to a solution of the biocompatible hydrophobic polymer in a polar solvent to provide a first liquid mixture, nb) adding the first liquid mixture to an aqueous solution of a biocompatible surfactant under sonication to obtain a second liquid mixture, nc) maintaining the sonication of the second liquid mixture while cooling, nd) evaporating the polar solvent from the second liquid mixture to obtain a suspension of beads comprising the biocompatible hydrophobic polymer, the perfluorocarbon and optionally the metal compound, ne) separating the beads from the suspension and preparing a water suspension of the beads and nf) freeze-drying the water suspension to obtain the beads, nwherein the addition of the first liquid mixture to the biocompatible surfactant in step b) is performed within a period of at most 10 seconds, nwherein the sonication in step b) and the sonication in step c) are performed by a probe at an amplitude of at least 240 µm for 1-10 minutes and nwherein the weight ratio of the biocompatible surfactant to the biocompatible hydrophobic polymer is at least 3:1. |