title: Study of the physicochemical properties of trimethoprim with beta-cyclodextrin in solution.
abstract: The behavior of trimethoprim (TMP) in aqueous solutions containing different concentration of beta-cyclodextrin (beta-CD) was characterized by the solubility method, UV spectrophotometry and differential scanning calorimetry (DSC). The UV spectra enhancement of TMP as result of complex with beta-CD was investigated. Complexation with beta-CD increase the TMP aqueous solubility and the phase solubility diagram was A(L) type. Thermodynamic parameters of the complex process, K, DeltaG, DeltaH and DeltaS, were determined from the phase solubility diagram at 298 and 318 K, respectively. The experimental results indicated that the complex process was an enthalpy-driven process. Mechanism of the complex of beta-CD with TMP was further discussed using the molecular model program. Results showed that the 3,4,5-trimethoxybenzyl group of the TMP was partly embedded in the cavity of beta-CD.
authors.affiliation: College of Pharmaceuticals and Biotechnology, Tianjin University, Tianjin 300072, PR China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Yun-Hui
authors.initials: YH
authors.lastname: Zhang
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Xiong
authors.forename: Zhi-Geng
authors.initials: ZG
authors.lastname: Li
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Jin
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D002152:Calorimetry, Differential Scanning / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013816:Thermodynamics; D014295:Trimethoprim / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D012996:Solutions; D047392:beta-Cyclodextrins; D014295:Trimethoprim