Miyake K, Hirayama F, Uekama K
Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan.
J Pharm Sci. 1999 Jan;88(1):39-45. doi: 10.1021/js980284+.
The interaction of cyclosporin A (CsA) with dimethyl-alpha- and -beta-cyclodextrins (DM-alpha-CyD and DM-beta-CyD) was investigated by the solubility method, electrospray ionization mass spectrometry (ESI-MS) and 1H-nuclear magnetic resonance spectroscopy (1H NMR). The extremely low solubility (1.9 x 10(-5) M at 25 degreesC) of CsA in water was significantly improved by the complexation with DM-CyDs: for example, the solubility increased 87-fold in the presence of 5.0 x 10(-2) M DM-beta-CyD. The phase solubility diagram of CsA/DM-CyD systems showed an Ap type and the stability constants (1060 M-1 and 1050 M-1, respectively) of the 1:1 CsA/DM-alpha-CyD and CsA/DM-beta-CyD complexes were much higher than those of the 1:2 complexes (15 M-1 and 21 M-1, respectively). In ESI-MS spectra of the CsA/DM-beta-CyD system, a new signal emerged at 1268 which corresponds to the 1:1 adduct of the di-ionized guest molecule with the host molecule. This signal intensity was significantly decreased by the addition of chlorpromazine (CPZ) which has a large stability constant (8800 M-1) of the DM-beta-CyD complex, whereas the signal corresponding to the CPZ/DM-beta-CyD complex was little affected by the addition of CsA, indicating a competitive inclusion of CPZ and CsA within the host cavity. CsA gave many new peaks in the 1H NMR spectrum when the solvent was changed from chloroform to methanol/water, suggesting conformational diversity of CsA in polar solvents. Inspection of 1H-chemical shift changes and the two-dimensional rotating frame nuclear Overhauser effect (ROESY) spectra of the CsA/DM-CyD system suggested that the side chains of amino acids in CsA molecule take part in the inclusion within DM-CyDs, although there is seemingly no preference of particular amino acid residues. All the data obtained here suggested that CsA forms inclusion complexes with DM-alpha- and -beta-CyDs in an aqueous medium and side chains of CsA are mainly involved in the inclusion.
采用溶解度法、电喷雾电离质谱（ESI-MS）和1H-核磁共振波谱（1H NMR）研究了环孢菌素A（CsA）与二甲基-α-和-β-环糊精（DM-α-CyD和DM-β-CyD）的相互作用。CsA在水中的溶解度极低（25℃时为1.9×10-5 M），与DM-CyDs形成络合物后其溶解度显著提高：例如，在5.0×10-2 M DM-β-CyD存在下，溶解度增加了87倍。CsA/DM-CyD体系的相溶解度图显示为Ap型，1:1的CsA/DM-α-CyD和CsA/DM-β-CyD络合物的稳定常数（分别为1060 M-1和1050 M-1）远高于1:2络合物（分别为15 M-1和21 M-1）。在CsA/DM-β-CyD体系的ESI-MS谱图中，在1268处出现了一个新信号，它对应于双离子化客体分子与主体分子的1:1加合物。加入氯丙嗪（CPZ）后，该信号强度显著降低，氯丙嗪与DM-β-CyD络合物的稳定常数较大（8800 M-1），而对应于CPZ/DM-β-CyD络合物的信号受CsA加入的影响很小，表明CPZ和CsA在主体腔内存在竞争性包合。当溶剂从氯仿变为甲醇/水时，CsA在1H NMR谱图中出现了许多新峰，这表明CsA在极性溶剂中存在构象多样性。对CsA/DM-CyD体系的1H化学位移变化和二维旋转框架核Overhauser效应（ROESY）谱图的考察表明，CsA分子中氨基酸的侧链参与了DM-CyDs的包合，尽管似乎没有特定氨基酸残基的偏好。此处获得的所有数据表明，CsA在水性介质中与DM-α-和-β-环糊精形成包合物，且CsA的侧链主要参与包合。
