title: Comparison of simple Eudragit microparticles loaded with prednisolone and Eudragit-coated chitosan-succinyl-prednisolone conjugate microparticles: Part I. Particle characteristics and in vitro evaluation as a colonic delivery system.
abstract: OBJECTIVE
  Simple Eudragit microparticles loaded with prednisolone and chitosan-succinyl-prednisolone conjugate microparticles coated with Eudragit were prepared and characterized in vitro in order to obtain their basic features as a colonic delivery system.
  
  
  METHODS
  Both types of microparticles were prepared by the emulsification-solvent evaporation modified somewhat from the previous one. Their particle size, shape and their drug content were investigated, and in vitro release profiles were examined using JP-15 1st fluid (pH 1.2), JP-15 2nd fluid (pH 6.8) and PBS (pH 7.4) as release media. Furthermore, the regeneration of conjugate microparticles from Eudragit-coated microparticles was investigated under the same incubation conditions.
  
  
  RESULTS
  Simple Eudragit S100 (EuS) microparticles (ES-M) were almost spherical, ca. 1.2 μm diameter, and PD content ca. 3.7% (w/w). Conjugate microparticles (CS-M1) and EuS-coated conjugate microparticles (CS-M1/S) had particle sizes of ca. 2.8 and 15.3 μm, respectively, and PD contents of 5.4 and 2.1% (w/w), respectively. ES-M exhibited suppressed release at pH 1.2, gradual release at pH 6.8 and rapid release at pH 7.4. CS-M1 showed no release at pH 1.2, and very slow release at pH 6.8 and 7.4. CS-M1 regenerated poorly from CS-M1/S at pH 6.8.
  
  
  CONCLUSIONS
  Simple Eudragit micrparticles and Eudragit-caoted conjugate microparticles, prepared by the present methods, were found in vitro to be possibly useful as the delivery systems of PD to the lower intestine, although there were differences in their release rate and morphological features.
authors.affiliation: Department of Drug Delivery Research, Hoshi University, Ebara, Shinagawa-ku, Tokyo, Japan. onishi@hoshi.ac.jp
authors.forename: Hiraku
authors.initials: H
authors.lastname: Onishi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Machida
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D048271:Chitosan / Q000737:chemistry*; D003106:Colon / Q000378:metabolism; D016503:Drug Delivery Systems; D065546:Drug Liberation; D005938:Glucocorticoids / Q000008:administration & dosage / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D010316:Particle Size; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011239:Prednisolone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D005938:Glucocorticoids; D011109:Polymethacrylic Acids; C038300:methylmethacrylate-methacrylic acid copolymer; D048271:Chitosan; D011239:Prednisolone; C021322:prednisolone hemisuccinate