Four polymorphic forms of carbamazepine have been simultaneously investigated by ¹H NMR and ¹⁴N NQR. The results show that the proton spin-lattice relaxation time and the ¹⁴N NQR spectra can be used to differentiate between various polymorphic forms. Spontaneous transformations from Form II to Form III and from Form IV to Form III have been investigated through their influence on the ¹⁴N NQR spectrum and the proton NMR signal and spin-lattice relaxation. The ¹⁴N NQR spectra prove that in the observed polymorphic forms of carbamazepine the hydrogen bonded dimers of carbamazepine molecules are the basic elements of the crystal structure. The dimers are centrosymmetric in Forms III and IV and in metastable polymorphic form occurring during the transformation of Form IV to Form III. Two non-equivalent molecular positions are observed in Form II with the occupation ratio 1:1 and in Form I with the occupation ratio either 2:1 or 3:1. The ¹⁴N NQR data are related to the published crystal structures. Possible reasons for the mismatch of the X-ray and NQR data for Forms I and II are discussed.

卡马西平的四种多晶型形式已通过¹ H NMR和¹⁴ N NQR同时研究。结果表明，质子自旋晶格弛豫时间和¹⁴ N NQR光谱可用于区分各种多态形式。已经研究了从晶型II到晶型III以及晶型IV到晶型III的自发转变，它们对¹⁴ N NQR光谱，质子NMR信号和自旋晶格弛豫的影响。在¹⁴N NQR光谱证明，在观察到的卡马西平多晶型物中，卡马西平分子的氢键二聚体是晶体结构的基本元素。二聚体在形式III和IV中是中心对称的，并且在形式IV向形式III的转化过程中以亚稳态多态形式存在。在形式II中，占有率为1：1的两个非等价分子位置在形式II中以2：1或3：1的占有率的形式观察到。在^14个ÑNQR数据都与发表的晶体结构。讨论了形式I和形式II的X射线和NQR数据不匹配的可能原因。