Makoto UminoKenjirou HigashiHyuma MasuWaree LimwikrantKeiji YamamotoKunikazu MoribeChiba UniversityMahidol University2018-10-192018-10-192013-01-01Journal of Pharmaceutical Sciences. Vol.102, No.8 (2013), 2738-274715206017002235492-s2.0-84881024933https://repository.li.mahidol.ac.th/handle/123456789/32762We characterized cromolyn sodium (CS) hydrates and evaluated their molecular states in low-dose formulations using Na-multiquantum magic-angle spinning (MQMAS) nuclear magnetic resonance (NMR) analysis. Two CS hydrates, low-water-content hydrated form and high-water-content hydrated form containing 2-3 and 5-6 hydrates, respectively, were prepared by humidification. Single-crystal X-ray diffraction and powder X-ray diffraction analysis revealed that these CS hydrates contained sodium channel structures and that water molecules were adsorbed on the sodium nucleus.13C-cross-polarization/MAS NMR spectra of these hydrates revealed similar results, confirming that the water molecules were adsorbed not on the cromolyn skeletons but mainly on the sodium nucleus. In contrast,23Na-MQMAS NMR analysis allowed us to clearly distinguish these hydrates without discernible effects from quadrupolar interaction. Thus, MQMAS NMR analysis is a valuable tool for evaluating salt drugs and their formulations. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.Mahidol UniversityPharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1002/jps.23655