| abstract |
A preparation containing covered magnetic particles, wherein the covered magnetic particles, each includes magnetic microparticles with a bonded organic compound and covered with a vesicular lipid membrane, and an organic compound having at least two groups selected from the group consisting of a hydroxyl group, a carboxyl group, a carbamoyl group, an amino group, a mercapto group, a sulfo group, a dithio group, a thiocarboxyl group and a dithiocarboxyl group and the cover magnetic particles satisfy the following equation: 0.05 ≤ R / r × 100 ≤ 1.5 n(R represents an average particle size of the covered magnetic particles and r represents an average particle size of magnetic microparticles). |