Controlled release particles

1. A controlled release particle consisting of:

a core

formed by suspension polymerization of a core ingredient component containing an antibiotic compound and a first polymerizable vinyl monomer, the core ingredient component being prepared in the absence of a solvent and thus the core ingredient component is solvent-free and

containing a first polymer of the first polymerizable vinyl monomer, and the antibiotic compound present in the first polymer; and

a shell

formed by suspension polymerization of a second polymerizable vinyl monomer having affinity with water of the same or higher than that of the first polymerizable vinyl monomer,

containing a second polymer obtained from the second polymerizable vinyl monomer, and

covering the core,

wherein the antibiotic compound is dispersed in a matrix composed of the first polymer in the core.