Journal of Physical Chemistry & Biophysics
Open Access

Abstract

Study of Intermolecular Interaction of Hydroxypropyl-β-cyclodextrin Complexes through Phase Diagrams of the Fusion Entropy: Contrast between Nifedipine and Nicardipine Hydrochloride

Yingpeng Li, Satoru Goto, Yohsuke Shimada, Kazushi Komatsu, Yuusaku Yokoyama, Hiroshi Terada and Kimiko Makino

In amorphous state, we examined the intermolecular interactions between the guest drugs nifedipine (NIF) and nicardipine hydrochloride (NIC), which are 1,4-dihydropyridine calcium channel blockers, and a host hydroxypropyl-β-cyclodextrin (HP- β-CD). Differential scanning calorimetry and powder X-ray diffraction showed that the interaction of NIC with HP-β-CD was remarkable stronger than that of NIF for both preparation methods. The structure of amorphous state complex of NIF/HP-β- CD presented as inclusion complex, and HP-β-CD in NIC/HP-β-CD complex was more like a surfactant which around NIC with its out-surface in any ratio. Fourier transform-infrared spectroscopy showed that the NIC/HP-β-CD complex contained multiple contact groups, whereas the NIF/HP-β-CD complex contained a single site bound to the HP-β-CD. Further, molecular dynamics simulation exhibited a much more vehemently reaction trend in NIC/HP-β-CD complex than that in NIF/HP-β-CD using compare the reaction constant. From the simulation images of NIF and NIC binding to HP-β-CD, we insure the different including situation in amorphous state of NIF/HP-β-CD and NIC/HP-β-CD. Consequently, we speculated that NIC binding to HP-β-CD with a different mechanism with NIF/ HP-β-CD complex. And this unique binding method may lead NIC has a higher potential energy changing in forming amorphous complexes.