title: Influence of particle design on oral absorption of poorly water-soluble drug in a silica particle-supercritical fluid system.
abstract: The physicochemical characteristics and oral absorption of a poorly water-soluble drug, K-832, adsorbed onto porous silica (Sylysia 350), were compared with those of K-832 adsorbed onto non-porous silica (Aerosil 200). K-832 and silica were treated with supercritical CO(2) (scCO(2)) to produce K-832-Sylysia 350 and K-832-Aerosil 200 formulations. Scanning electron microscopy, polarizing microscopy, powder X-ray diffraction, and differential scanning calorimetry results suggested that K-832 mainly existed in an amorphous state in both formulations. The specific surface area of both formulations was much larger than that of pure K-832 crystals. The dissolution rate of K-832 from both formulations was considerably greater than that from corresponding physical mixtures due to rapid wetting of the hydrophilic carrier surfaces and amorphous state, the dissolution from the K-832-Sylysia 350 formulation being the fastest. In vivo absorption tests on the two formulations indicated no significant differences in their peak concentration (C(max)) and the area under their plasma concentration-time curve (AUC), while the concentrations of K-832 in the K-832-Sylysia 350 formulation were significantly higher than those in the K-832-Aerosil 200 formulation 1 h and 1.5 h after administration of these formulations (p<0.05). This could be attributed to the different dispersion states of K-832 in the formulations due to their different three-dimensional structures (porous and non-porous). In physical stability tests, the amorphous drugs in both formulations were stable at room temperature for at least 14 months. Thus, the absorption of poorly water-soluble drugs could be greatly improved by adsorption onto porous silica using scCO(2).
authors.affiliation: Fuji Research Laboratories, Pharmaceutical Division, Kowa Co. Ltd., 332–1 Ohnoshinden, Fuji, Shizuoka, Japan. h-miura@kowa.co.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miura
authors.forename: Makoto
authors.initials: M
authors.lastname: Kanebako
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shirai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakao
authors.forename: Toshio
authors.initials: T
authors.lastname: Inagi
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Terada
mesh_terms: D000042:Absorption; D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D004285:Dogs; D010316:Particle Size; D016062:Porosity; D011724:Pyridazines / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D013440:Sulfides / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: C555018:2-benzyl-5-(4-chlorophenyl)-6-(4-(methylthio)phenyl)-2H-pyridazin-3-one; D011724:Pyridazines; D013440:Sulfides; D014867:Water; D012822:Silicon Dioxide