Preparation Of Wu-Chu-Yu Extracts And Study Of Relationship Of The Purities And Absorption Of Rutaecarpine And Evodiamine In Them After Oral Administration In Rats

OBJECTIVETo prepare Wu-Chu-Yu extract with different purities and evaluate the the pharmacokinetic parameters of rutaecarpine (Rut) and evodiamine (Evo) in Wu-Chu-Yu extracts with different purities after oral administration and relationship of purity and absorption. To explore possible method to improve the bioavailability of Rut and Evo, provide foundation for the development of Wu-Chu-Yu and new idea of dosage design of insoluble compounds.METHODS and RESULTSFirstly, the concentration determination method of Rut and Evo in Wu-Chu-Yu was set up by HPLC.Evaluated by extraction rate, the extraction method and herb treated method were screened with single-factor tests.The extraction technology screenings were carried by orthogonal experiment design of ethanol consumption, ethanol concentration, extraction time and extraction times.The optimum technology conditions were:ethanol consumption(12 times of herb), ethanol concentration (60%), extraction time(1.5 h) and extraction times (3 times).The crude products were purified by dissolving with ethanol and precipitating gradually with adding water. Detected by Thin-Lyaer Chromatography, the purify technology screenings were carried by examining the ethanol concentration and volume and volume of adding water. The optimum technology was:crude products were resolved in 20 volumes of 90% ethanol.Water was slowly added to this extracted solution step by step until ethanol final concentration reached 45%,33% and 25%.Recrystallized in methanol,precipitations of three different purities were collected respectively. The concentrations of Rut and Evo were detected by HPLC,which were 45 and 35%(High purity),28 and 21%(medium purity),9%and 7%(low purity) in the three kinds of sample.An HPLC method was set up to determine the concentrations of Rut and Evo in rat blood. Male Sprague-Dawley rats were given Wu-Chu-Yu extracts with different purities (high, medium and low) approximately the same dose of Rut (40mg·kg-1)and Evo (31 mg·kg-1).At different time points (0.25,0.5,0.75,1,1.5,2,2.5,3 and 4 h) after administration, the concentrations of Rut and Evo in rat blood were determined by HPLC, and main pharmacokinetic parameters were measured by DAS 2.0 software. There were statistically significant differences (p<0.01)in pharmacokinetic parameters of Rut and Evo among these groups, while Cmaxand AUCo-4 increased with the increase of purity. This suggested that the increase of purity could promote the absoption and bioavailability of Rut and Evo.The results indicated that the absorption of Rut and Evo in Wu-Chu-Yu extracts can be improved compared with the pure Rut and Evo.The relationship of increase of extracts purity and increase of bioavailability may be true in certain scope. The absorption and bioavailability may decrease with the increase of purity when it exceed the upper limit.CONCLUSIONWu-Chu-Yu extracts can improve the absorption and bioavailability of Rut and Evo compared with the pure drugs.The bioavailability inceased with the increase of purity in scope of 16%-80% (the ratio of Rut and Evo was 13:10).The impurities in extracts may decline and block the absorption of Rut and Evo and the extent of this reaction was related to the content of impurities.