Abstract: Aim To study the interaction of puerarin (PU) with phospholipid (PL) in solid dispersion. Methods PU/PL solid dispersion was prepared with solvent evaporation and the interaction between PU and PL was studied by analysis of their ultraviolet spectra, infrared spectra, ¹H NMR spectra and thin layer chromatogram. Results In chloroform the maximum absorption peak of PU in PU/PL mixture was located at 243 nm, but 251 nm for that of PU in solid dispersion. However in methanol, QU in mixture or solid dispersion had the same maximum absorption peak location in ultraviolet spectra. Compared with the infrared spectra of mixture, that of solid dispersion showed the specific absorption peak location of benzene ring framework in PU molecule was markedly changed, the stretching vibration peak of P=O in PL molecule was shifted to high wave numbers and the stretching vibration peak of C=C in PL molecule was disappeared. In 1H NMR spectra, most of the signals from PU in solid dispersion were weaken markedly or disappeared and the signals from the polar partof PL molecule were significantly changed. PU and PL in solid dispersion could be separated on silica gel plate with the mixed solvent of chloroform, methanol and water (65:25:5) or ethyl acetate and methanol (10:1). Conclusion In soliddispersion the benzene ring framework of PU molecule could act with the polar part and unsaturated part of PL moleculethrough charges fransfer, and the interacted part could be surrounded by fat chains of PL molecule.

Key words: puerarin, puerarin, phospholipid, phospholipid, solid dispersion, solid dispersion, nucleus magnetic resonance, nucleus magnetic resonance