Physical properties of four polymorphic forms of sulfanilamide I: Densities, refractive indexes, and X-ray diffraction measurements

Effects of polymorphic differences for sulfanilamide, as seen through 13C and 15N solid‐state NMR, together with shielding calculations

“…14,15,22 We have recently determined the crystal structure of a new polymorph, but have not been able to produce a sufficient quantity of pure material for spectroscopic characterization. Its calculated powder XRD pattern and stability indicate that it is not the υ polymorph reported by Sekiguchi et al 14 An unstable anhydrate appears erratically during attempts to crystallize sulfanilamide polymorphs from aqueous solution.…”

“…Here we report a re-investigation of the 13 C NMR spectra of the sulfanilamide polymorphs, with a clarification of the assignments, aided by a study of the proton spin-lattice relaxation times in the laboratory and rotating frames, T 1 (H) and T 1 (H), respectively. We also measured the high-resolution 15 N CP/MAS spectra of 15 N-enriched samples for all the three solid forms for the first time. The value of 15 N spectra as an aid to the understanding of polymorphic behaviour has been shown previously in respect of dyestuffs 28,29 and pharmaceuticals.…”

“…We also measured the high-resolution 15 N CP/MAS spectra of 15 N-enriched samples for all the three solid forms for the first time. The value of 15 N spectra as an aid to the understanding of polymorphic behaviour has been shown previously in respect of dyestuffs 28,29 and pharmaceuticals. 30 In the present work, the separate enrichment of sulfanilamide at the N(1) and the N(2) positions allowed an insight into molecular mobility.…”

Towards Understanding Drugs on the Molecular Level to Design Drugs of Desired Profiles

“…The forms and are considered to be enantiotropically related. The origins of polymorphism of sulfanilamide were found to be connected with the versatile hydrogen-bonding capabilities [154]. The differences in the chemical shifts at 13 C and at 15 N permitting the distinction between individual polymorphs Table 5, [156] are of the same order as in glycine.…”

“…In the solid state, it crystallizes in four forms , , , [149][150][151] and [152][153][154] fully investigated by XRD. The different d-spacing of three strongest XRD diffraction lines (4.91, 6.57, 3.57; 6.12, 4.49, 4.23; and 3.90, 3.78, 33.6 for , , , respectively) allows easy distinction of each polymorph.…”