Quantitative H NMR method for analyzing primaquine diphosphate in active pharmaceutical ingredients.

Thermal analysis, Fourier Transform IR, the isotropic chemical shift of H NMR in different solvents, their temperature dependence and spin-lattice relaxation time constant (T), solution 1D and 2D NMR, and solid-state C and P NMR (magic angle spinning NMR) were employed to obtain full information and elucidate the structures of primaquine diphosphate (PQD) samples used for quality controlling malaria medicines. Additionally, a simple, rapid, specific, and reliable quantitative method (qNMR) was developed to determine the PQD level in the raw material of active pharmaceutical ingredients (APIs). The method was developed using ethylene carbonate (EC) as the internal standard and dimethylsulfoxide-d (DMSO-d) as the NMR solvent.