title: Application of silver ion in the separation of macrolide antibiotic components by high-speed counter-current chromatography.
abstract: Three macrolide antibiotic components - ascomycin, tacrolimus and dihydrotacrolimus - were separated and purified by silver ion high-speed counter-current chromatography (HSCCC). The solvent system consisted of n-hexane-tert-butyl methyl ether-methanol-water (1:3:6:5, v/v) and silver nitrate (0.10mol/l). The silver ion acted as a pi-complexing agent with tacrolimus because of its extra side double bond compared with ascomycin and dihydrotacrolimus. This complexation modified the partition coefficient values and the separation factors of the three components. As a result, ascomycin, tacrolimus and dihydrotacrolimus were purified from 150mg extracted crude sample with purities of 97.6%, 98.7% and 96.5%, respectively, and yields over 80% (including their tautomers). These results cannot be achieved with the same solvent system but without the addition of silver ion.
authors.affiliation: Fujian Institute of Microbiology, Fuzhou, China.
authors.forename: Yaoming
authors.initials: Y
authors.lastname: Wen
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Wang
authors.forename: Xiuming
authors.initials: X
authors.lastname: Chen
authors.forename: Zhanxian
authors.initials: Z
authors.lastname: Le
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification*; D003377:Countercurrent Distribution / Q000379:methods*; D007477:Ions / Q000737:chemistry*; D018942:Macrolides / Q000737:chemistry / Q000302:isolation & purification*; D012834:Silver / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D007477:Ions; D018942:Macrolides; D012834:Silver