Simultaneous analysis of Cu and Pb as ABEDTA complexes in Rhizoma coptidis by capillary electrophoresis coupled with solid phase extraction

A novel capillary electrophoresis method for simultaneous determination of Cu and Pb has been developed in this paper.Cu（Ⅱ） and Pb（Ⅱ） ions were reacted with ABEDTA to form complex to achieve an ideal sensitivity of heavy metal complexes.The digestion solution of Rhizoma coptidis drug sample was purified by neutral Al_2O_3 column chromatography and the chromatographic behavior of metal-L complexes was investigated.The calibration curve was linear in the range of 5-60μg/mL for Cu^（2＋） and 5-25μg/mL for Pb^（2＋） with the correlation coefficients 0.9970 and 0.9972 for each（n = 5）.The average recoveries were 86.2%for Pb and 90.1%for Cu,while the relative standard deviations were 5.1%and 3.6%respectively.The method was successfully applied to determine Cu and Pb in R.coptidis drug samples.

Chelatometric dispersive liquid-liquid microextraction followed by capillary electrophoresis for the analysis of total and water soluble copper in Rhizoma coptidis

A new method for the analysis of copper and its speciation in Rhizoma coptidis was proposed using chelatometric dispersive liquid-liquid microextraction（cDLLME） followed by capillary electrophoresis. Dithizone was used as a chelating agent for extraction and carbon tetrachloride and ethanol were used as extraction and dispersive solvent,respectively.The calibration curve was linear in the range of 0.5- 20.0μg/mL with a correlation coefficient of 0.9990（n = 6） and the average recovery was in the range of 88.26%-94.44%.The method was successfully used to determine the total and water soluble copper in Rhizoma coptidis herbal medicine.The results suggested that it would be reasonable to setting the criterion of heavy metals in an herbal medicine according to the dosage forms.

Herb-drug enzyme-mediated interactions and the associated experimental methods： a review

OBJECTIVE: To review the interactions between herbs and widely used drugs and summarize the associated experimental methods.METHODS: Definite herb-drug interactions were obtained by searching Pub Med, other large overseas databases and summarizing new researches from China. We summarize some methods to assess the interaction between herbs and drugs involving microsomal, cell culture and animal experiments, and clinical trials, classifying this method as single ingredient herbs, crude herb extracts, andherbal formulae.RESULTS: Many herbs interact with drugs through a complex cytochrome P450 and/or P-glycoprotein mechanism. Herb-induced enzyme inhibition and/or induction may result in enhanced and / or decreased plasma, tissue, urine and bile drug concentrations, leading to a change in a drug's pharmacokinetic parameters and resulting in the improper treatment of patients and potentially severe side effects. Use of an appropriate method for comprehensively assessing herb-drug interactions can minimize clinical risks. Different methods were used by researchers to assess the pharmacological changes of drugs in vivo and in vitro and the mechanisms of the interactions from microsomal, cell culture and animal experiments, and clinical trials are discussed in this review.CONCLUSION: Co-medication with herbs can result in changes in pharmacological effects of many drugs. This review describes the assessment of single-ingredient herbs, crude herb extracts, and herbal formulae. When choosing a research method to investigate herb-drug interactions, the properties of the drugs and herbs should be considered.