Molecular interactions of etiracetam and water in solution

Active pharmaceutical ingredient (APIs) are frequently delivered to the patient in the solid-state as part of an approved dosage form (e.g., tablets, capsules, etc.). Drug compounds tend to crystallise into different crystal forms, some of which incorporate solvent (water). We are investigating the factors leading to water incorporation. RS-Etiracetam exists in two polymorphs and a monohydrate, but its enantiomer S-Etiracetam does not form either polymorph or hydrate. Our preliminary data shows interaction between the NH2 and C=O moieties and water, which is potentially critical for the formation of the monohydrate but does not explain the different solid-state behaviour between the racemate and the enantiomer. We thus propose to measure neutron total scattering on SANDALS for RS-Etiracetam and S-Etiracetam to elucidate why the racemate forms a hydrate and the pure enantiomer does not.