title: Crystal Structures and Vapor-Induced Crystalline Transformation of 7-Ethyl-10-Hydroxycamptothecin Pseudopolymorphs.
abstract: Solvent-induced 3 frameworks (the monohydrate, methanol solvate, and dimethyl formamide [DMF] solvate) of an anticancer drug, 7-ethyl-10-hydroxycamptothecin (SN38), were constructed. The crystal structures of the 3 pseudopolymorphs were characterized by single-crystal X-ray diffraction technique for the first time. Crystal structure analysis of all these polymorphs revealed that the monohydrate showed 3D frameworks linked by hydrogen bonds. In the methanol solvate, the 1D molecular chains were linked by the methanol molecules through intermolecular hydrogen bonds to form a 2D sheet. The DMF solvate exhibits the 1D hydrogen bonding-linked chains along b-axis. Vapor-induced transformation has been investigated for the monohydrate, the methanol solvate, and the DMF solvate. The conversion relationships among the 3 solid frameworks are illustrated. Insights regarding transformation mechanisms have been established from consideration of the crystal structures.
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China. Electronic address: icmwl@sdu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China.
authors.forename: Changlin
authors.initials: C
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Song
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China.
authors.forename: Zexin
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, No. 27 Shanda South Road, Jinan 250100, China.
authors.forename: Xutang
authors.initials: X
authors.lastname: Tao
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000737:chemistry; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D004126:Dimethylformamide / Q000737:chemistry; D006860:Hydrogen Bonding; D000077146:Irinotecan; D000432:Methanol / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D012997:Solvents; D000077146:Irinotecan; D004126:Dimethylformamide; D002166:Camptothecin; D000432:Methanol
keywords: crystal structure; crystallization; hydrates/solvates; pseudopolymorph; transformation