2.3. NMR Sample Preparation

Ibuprofen and the lipids were mixed in the desired molar ratios in chloroform. After evaporation of the solvent, the samples were redissolved in cyclohexane and lyophilized overnight resulting in ~15 mg overall dry sample for ¹H-NMR and ~3 mg for ³¹P/²H-NMR measurements. After hydration with 40wt% D₂O or H₂O for ¹H-NMR and ²H-NMR measurements, respectively, the samples were equilibrated by ten freeze–thaw cycles and gentle centrifugation. In the end, the samples were transferred into 4 mm HR MAS rotors with spherical Kel-F (15 µL volume) inserts for ¹H-NMR or 5 mm glass vials for ³¹P and ²H-NMR or measurements.