An efficient method for the simultaneous quantification of three flavone aglycones was developed and validated for the control of flavonoids in Flos Chrysanthemi （FC）. The method employed mixed solvent of hydrochloric acid （HC1） and methanol to extract and hydrolyze flavone glycosides simultaneously from powdered FC followed by HPLC to determine the contents of three flavone aglycones, luteolin, apigenin and diosmetin, which are the major bioactive flavones in FC. The extraction and hydrolysis conditions optimized by the orthogonal tests were as follows： powdered FC was refluxed in 80% methanol （v/v） containing 2.4 M HC1 for 2 h in 80 ℃ water bath. The HPLC separation was performed on C18 column and detected with DAD at 344 nm. The calibration curves for luteolin, apigenin and diosmetin were linear over the ranges of 2.233-71.46 μg/mL, 1.668-53.38 μg/mL and 1.410-45.11 μg/mL, their assay recoveries were 100.3%, 103.9% and 100.4%, their intra-day repeatability （R.S.D.） were 0.68%, 0.21% and 0.38% and their inter-day repeatability were 2.6%, 1.7% and 2.0%, respectively. The developed method has been successfully utilized to assay eight species of popular FC samples, especially to analyze Hangbaiju, the well-known FC in China.
Membrane transporters mediate the influx and efflux of various drugs,and play essential roles in drug absorption,distribution,metabolism and excretion（ADME）.The unique characteristics of membranes transporters potentiate them as targets for developing drugs with ideal pharmacokinetics profiles,including targeted distribution,improved clinical efficacy and low adverse reaction.In this review,we summarize the tissue-specific expression,transport functions and substrates profiles of the major influx and efflux transporters,including solute carrier（SLC） superfamily and adenosine triphosphate（ATP）-binding cassette（ABC） superfamily.Moreover,we describe examples of successful drug or prodrug design based on the function of transporters that yielded drugs with excellent ADME properties.Lastly,we discuss the in vitro and in vivo methods that are broadly applied in the drug designing process to study the interactions between the drugs and the transporters.
