Abstract: The present invention is to provide a sustained release preparation comprising a drug-containing core substance and a multilayered coating layer covering the core substance, wherein all adjacent layers in the multilayered coating layer contain mutually different hydrophobic organic compound-water-soluble polymer mixtures; and, a method of producing a sustained release preparation, having a multilayered coating layer in which adjacent layers contain different hydrophobic organic compound-water-soluble polymer mixtures, which comprises spray-coating a solution containing a hydrophobic organic compound-water-soluble polymer mixture onto a drug-containing core substance, continuing to spray-coat a solution containing a different hydrophobic organic compound-water-soluble polymer mixture onto the resulting coating layer, and repeating this step.

Abstract: The present invention discloses an efficient preparation method of spherical fine particles containing a drug for an easily-swallowed, controlled-release preparation comprising the production of drug-containing spherical fine particles (mean particle size: 60-200 &mgr;m) by adding a binder solution to a mixture containing an excipient powder having the property of retaining solvent (and preferably having a mean length of the long axis of 40 &mgr;m or less) and a drug powder (preferably having a mean length of the long axis of 50 &mgr;m or less), followed by high-speed mixing granulation.

Abstract: The present invention discloses sustained release particles having a mean particle size of 300 &mgr;m, or less, comprising a drug-containing core substance coated with a mixed coating of a hydrophobic organic compound-water-insoluble polymer, which prevents sticking during compression molding when producing oral sustained release tablets, a preparation method of those sustained release particles, and a preparation method of tablets using those sustained release particles.

Abstract: The present invention is to provide a sustained release preparation comprising a drug-containing core substance and a multilayered coating layer covering the core substance, wherein all adjacent layers in the multilayered coating layer contain mutually different hydrophobic organic compound-water-soluble polymer mixtures; and, a method of producing a sustained release preparation, having a multilayered coating layer in which adjacent layers contain different hydrophobic organic compound-water-soluble polymer mixtures, which comprises spray-coating a solution containing a hydrophobic organic compound-water-soluble polymer mixture onto a drug-containing core substance, continuing to spray-coat a solution containing a different hydrophobic organic compound-water-soluble polymer mixture onto the resulting coating layer, and repeating this step.