title: Sustained-release microsphere formulation containing an agrochemical by polyurethane polymerization during an agitation granulation process.
abstract: In this report, a new solventless microencapsulation method by synthesizing polyurethane (PU) from polyol and isocyanate during an agglomeration process in a high-speed mixing apparatus was developed. Clothianidin (CTD), which is a neonicotinoid insecticide and highly effective against a wide variety of insect pests, was used as the model compound. The microencapsulated samples covered with PU (CTD microspheres) had a median diameter of <75μm and sustained-release properties. The CTD microspheres were analyzed by synchrotron X-ray computed tomography measurements. Multiple cores of CTD and other solid excipient were dispersed in PU. Although voids appeared in the CTD microspheres after CTD release, the spherical shape of the microspheres remained stable and no change in its framework was observed. The experimental release data were highly consistent with the Baker-Lonsdale model derived from drug release of spherical monolithic dispersions and consistent with the computed tomography measurements.
authors.affiliation: Health & Crop Sciences Research Laboratory, Sumitomo Chemical Co., Ltd., 4-2-1 Takatsukasa, Takarazuka, Hyogo 665-8555, Japan; Department of Pharmaceutical Engineering, Graduate Division of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Terada
authors.affiliation: Health & Crop Sciences Research Laboratory, Sumitomo Chemical Co., Ltd., 4-2-1 Takatsukasa, Takarazuka, Hyogo 665-8555, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Tagami
authors.affiliation: Health & Crop Sciences Research Laboratory, Sumitomo Chemical Co., Ltd., 4-2-1 Takatsukasa, Takarazuka, Hyogo 665-8555, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Ohtsubo
authors.affiliation: Department of Pharmaceutical Engineering, Graduate Division of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Iwao
authors.affiliation: Department of Pharmaceutical Engineering, Graduate Division of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Noguchi
authors.affiliation: Department of Pharmaceutical Engineering, Graduate Division of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. Electronic address: s-itai@u-shizuoka-ken.ac.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Itai
mesh_terms: D016573:Agrochemicals / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D008863:Microspheres; D058105:Polymerization; D011140:Polyurethanes / Q000737:chemistry*; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D016573:Agrochemicals; D003692:Delayed-Action Preparations; D011140:Polyurethanes
keywords: Agitation granulation; Agrochemical; Microsphere; Polyurethane; Sustained release