Moisture adsorption-desorption effect on the structure of inclusion complex of 6-chloro-2-pyridylmethyl nitrate and beta-cyclodextrin.
A new anti-anginal drug, 6-chloro-2-pyridylmethyl nitrate (FR46171), was found to form a complex with beta-cyclodextrin (beta-CyD), molecular ratio 1:1. The FR46171/beta-CyD complex thus prepared showed a moisture adsorption-desorption hysteresis characteristic of hydrophilic polymers. The moisture adsorption-desorption isotherm and differential scanning calorimetry indicated that the moisture adsorbed FR46171/beta-CyD complex includes 13-15 mol of water while the moisture desorbed complex includes 5 mol of water. X-ray diffraction patterns of these samples confirmed their different structures. The scanning electron photomicrographs and the surface areas (BET) suggested that the moisture adsorption-desorption hysteresis observed in FR46171/beta-CyD complex can be attributed to reversible hydrogen bonding between water molecules and hydroxyl groups.
Kitamura
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Analytical Research Laboratories, Fujisawa Pharmaceutical Co. Ltd, Osaka, Japan.
Koda
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Yasuda
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D000327:Adsorption; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003505:Cyclodextrins / Q000737:chemistry*; D004055:Differential Thermal Analysis; D006813:Humidity; D008855:Microscopy, Electron, Scanning; D011725:Pyridines / Q000737:chemistry*; D014961:X-Ray Diffraction; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D011725:Pyridines; D047392:beta-Cyclodextrins; C056182:6-chloro-2-pyridylmethyl nitrate; C031215:betadex