| Objectives1.To develop a HPLC(high performance liquid chromatography)method to measure the contents of venlafaxine and O-desmethylvenlafaxine(the bioactive product)in the blood,brain tissue,liver tissue,kidney tissue and gastric wall of rats.2.To explore the change rules of venlafaxine,O-desmethylvenlafaxine and total active ingredients(the sum of venlafaxine and O-desmethylvenlafaxine)in rats with the analytical method established.MethodsThe rats ' models were established through administration of venlafaxine hydrochloride.Extracted the rats' blood in 1 hour?2 hours?4 hours?6 hours and 8 hours,respectively.Then its organs such as brain,liver,kidney and gastric wall were removed.By using external standard method,the contents of venlafaxine and O-desmethylvenlafaxine were measured with HPLC.The distribution and metabolism regularities could be discovered by contrasting,analyzing the parameters.ResultsThe retention times of venlafaxine and O-desmethylvenlafaxine were 7.1 min and 5.1min,respectively.The proposed method was of less interference from impurities.The linearity ranges of venlafaxine in the blood,brain,liver,kidney and gastric wall were 0.8?10.0?g/mL,0.8?20.0?g/g,0.8-40.0?g/g,1.0?40.0?g/g,1.0?200.0?g/g.The linearity ranges of O-desmethylvenlafaxine in the blood,brain,liver,kidney and gastric wall were 0.8?10.0?g/mL,0.8?20.0?g/g,0.8?40.0?g/g,1.0?40.0?g/g,1.0?40.0?g/g.The minimal concentration of each linearity range was the limit of quantitation.The average extraction recoveries of venlafaxine in the blood were between 83.73%?91.53%under the concentrations of 1.0?g/mL,2.0?g/mL,4.0?g/mL,6.0?g/mL.The average recoveries of venlafaxine in the blood associated with the method were between 95.00%?103.22%.The average extraction recoveries of O-desmethylvenlafaxine in the blood were between 65.88%?71.66%under the concentrations of 1.0?g/mL,2.0?g/mL,4.0?g/mL,6.0?g/mL.The average recoveries of O-desmethylvenlafaxine in the blood associated with the method were between 93.68%?102.89%.The average extraction recoveries of venlafaxine in the brain tissue were between 78.74%?82.38%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of venlafaxine in the brain tissue associated with the method were between 93.95%?100.02%.The average extraction recoveries of O-desmethylvenlafaxine in the brain tissue were between 66.70%-71.88%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of O-desmethylvenlafaxine in the brain tissue associated with the method were between 93.97%?102.93%.The average extraction recoveries of venlafaxine in the liver tissue were between 76.34%?81.85%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of venlafaxine in the liver tissue associated with the method were between 96.86%?106.02%.The average extraction recoveries of O-desmethylvenlafaxine in the liver tissue were between 60.99%?65.42%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of O-desmethylvenlafaxine in the liver tissue associated with the method were between 94.86%?103.22%.The average extraction recoveries of venlafaxine in the kidney tissue were between 70.19%?77.43%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of venlafaxine in the kidney tissue associated with the method were between 104.93%?124.21%.The average extraction recoveries of O-desmethylvenlafaxine in the kidney tissue were between 62.92%?68.03 under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of O-desmethylvenlafaxine in the kidney tissue associated with the method were between 99.37%?123.20%.The average extraction recoveries of venlafaxine in the gastric wall were between 76.70%?92.23%under the concentrations of 2.0?g/mL,4.0?g/mL,6.0?g/mL,20.0?g/mL,100.0?g/mL.The average recoveries of venlafaxine in the gastric wall associated with the method were between 83.48%?105.42%.The average extraction recoveries of O-desmethylvenlafaxine in the gastric wall were between 62.84%?70.20%under the concentrations of 2.0?g/mL,6.0?g/mL,20.0?g/mL.The average recoveries of O-desmethylvenlafaxine in the gastric wall associated with the method were between 92.36%?104.17%.The concentrations of venlafaxine and O-desmethylvenlafaxine in the tissues of liver,kidney and gastric wall were high in 4 hours.And they were low in the blood and brain tissue.The main medicine existed in the blood and tissues were venlafaxine within 4 hours.The differences between contents of venlafaxine and O-desmethylvenlafaxine in the tissues were small after 4 hours.The concentrations of venlafaxine and O-desmethylvenlafaxine in the kidney tissue remained high long after administration.The contents of venlafaxine in the blood and gastric wall decreased with time.The trends of contents of venlafaxine in the other tissues rose at the beginning,then reduced.The metabolism of venlafaxine in the blood of rat was quick.The changes of concentrations of venlafaxine in the tissues were not apparent within 2 hours,There were considerable declines between 2 hours and 4 hours.The concentrations descended to the stable value after 4 hours.The trends of contents of O-desmethylvenlafaxine in the blood and tissues rose at the beginning,then reduced.The changes of contents were not obvious.The peak times of O-desmethylvenlafaxine were consistent with venlafaxine in all tissues.The total active ingredients in the tissues were mainly venlafaxine in 1 hour to 4 hours.The concentrations of venlafaxine were basically consistent with the concentrations of O-desmethylvenlafaxine in all tissues after 4 hours.The trends of total active ingredient contents in different tissues were basically consistent with the trends of venlafaxine.ConclusionsIn order to explore the change rules of venlafaxine and O-desmethylvenlafaxine in rats,the HPLC method was established and the contents were measured.The methodological validation show that the method established is of exclusive,stable and accurate in the determination and no residual effect.The conclutions can be drawn out from the results by statistical analysis:The kidney tissue can be made as the preferred sample in case samples with venlafaxine.The metabolism of venlafaxine in the blood of rat is quick.The main medicine existed in the tissues are venlafaxine within 4 hours.The differences between contents of venlafaxine and O-desmethylvenlafaxine in the tissues are small after 4 hours. |
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