“…Bupivacaine-fb (free base) and bupivacaine-HCl have very different solid-state NMR spectra, indicating that the molecules of these compounds pack in unique crystal forms. These results are consistent with different crystalline forms of pharmaceutical compounds having unique solid-state NMR spectra [15,16,17,18,19,20,21,22,23,24,25,26]. The solid-state forms of bupivacaine in a tristearin matrix and in a matrix made of lipid, water, and protein were also investigated.…”