Separation and Determination of Rhynchophylline and Isorhynchophylline in Uncaria rhynchophylla by HPLC with Ionic Liquid as Mobile Phase Additives / 中国药房

ABSTRACT

OBJECTIVE： To establish a method to determine the contents of rhynchophylline and isorhynchophylline in Uncaria rhynchophylla. METHODS： The separation degree of ionic liquid 1-butyl-3-methylimidazolium chloride （C4mimCl） as mobile phase additive was compared with that of mobile phase without additives and with traditional additive triethylamine （which damaged the chromatographic column）. The optimum concentration of C4mimCl was screened and the contents of rhynchophylline and isorhynchophylline in U. rhynchophylla from 4 habitats in Jiangxi province were determined by the newly established method. The determination was performed on Dikmatech Diamonsil Plus C18 column， the mobil phase was acetonitrile-buffer （0.1％ phosphoric acid+3.0 mmol/L C4mimCl）， gradient elution. UV detection wavelength was set at 245 nm and the flow rate was 1    mL/min. Sample size was 10 μL. RESULTS： When mobile phase had no additives or 3.0 mmol/L triethylamine and 3.0 mmol/L C4mimCl were added as additives， the separation of rhynchophylline from the front peak was 1.02， 1.23 and 1.72， and the separation from the back peak was 1.06， 6.00 and 4.25， respectively. The symmetry factors were 0.81， 0.86 and 1.13， respectively. The separation of isorhynchophylline from the front peak was 0.96， 3.89 and 4.05， and the separation from the back peak was 1.02， 2.34 and 2.36， respectively. The symmetry factors were 0.88， 0.81 and 0.96， respectively. The linear range of rhynchophylline and isorhynchophylline were 4.93-157.76 （r＝0.999 9） and 4.98-159.50 μg/mL （r＝1.000）， respectively. The quantitative limits were 0.486 4， 0.793 6 μg/mL， respectively. RSDs of precision， repeatability， stability and durability tests were all less than 5％ （n＝6）. The recovery rates were 102.9％-107.8％ （RSD＝1.7％，n＝6） and 95.4％-106.3％ （RSD＝3.9％，n＝6）， respectively. The content of rhynchophylline and isorhynchophylline in U. rhynchophylla from 4 habitats were 0.758-1.343         and 1.511-1.823 mg/g， respectively. CONCLUSIONS： Addition of C4mimCl into mobile phase can enhance its separation. Established HPLC method is rapid， accurate and reproducible， which can be used for content determination of rhynchophylline and isorhynchophylline in U. rhynchophylla.