Application of solid state NMR to pharmaceuticals

The influence of polymorphism on soUd state NMR can be illustrated by comparing the CP-MAS spectra of forms A-C of the histamine H2 antagonist cimetidine (7), shown in Fig. 4.12 [263]. The spectra of the three polymorphs are 

The application of the resonance assignment methods discussed in Section 4.5.3 enable a direct comparison between the chemical shifs of each atom in each polymorph, allowing an insight into the structural differences between the polymorphs [265]. Stractural information can also be obtained by the comparison of observed isotropic solid state chemical shifts with those calculated for particular molecular arrangements [266]. 

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R.K. Harris, Applications of solid-state NMR to pharmaceutical polymorphism and related matters, J. Pharm. Pharmacol. 59 (2) (2007) 225—239. 

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