title: Effect of particle size of drug on conversion of crystals to an amorphous state in a solid dispersion with crospovidone.
abstract: The effect of particle size on amorphization of drugs in a solid dispersion (SD) was investigated for two drugs, indomethacin (IM) and nifedipine (NP). The SD of drugs were prepared in a mixture with crospovidone by a variety of mechanical methods, and their properties investigated by particle sizing, thermal analysis, and powder X-ray diffraction. IM, which had an initial particle size of 1 µm and tends to aggregate, was forced through a sieve to break up the particles. NP, which had a large initial particle size, was jet-milled. In both cases, reduction of the particle size of the drugs enabled transition to an amorphous state below the melting point of the drug. The reduction in particle size is considered to enable increased contact between the crospovidone and drug particles, increasing interactions between the two compounds.
authors.affiliation: Department of Pharmaceutics and Biopharmaceutics, Showa Pharmaceutical University, Machida, Tokyo, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sugamura
authors.forename: Makiko
authors.initials: M
authors.lastname: Fujii
authors.forename: Sayaka
authors.initials: S
authors.lastname: Nakanishi
authors.forename: Ayako
authors.initials: A
authors.lastname: Suzuki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shibata
authors.forename: Naoya
authors.initials: N
authors.lastname: Koizumi
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003460:Crystallization; D004304:Dosage Forms; D010316:Particle Size; D011205:Povidone / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D004304:Dosage Forms; D011205:Povidone