| Total glucoside of paeony(TGP),a powdered substance extracted from roots of Paeonia lactiflora Pall,has been reported to have a significant therapeutic effect on rheumatoid arthritis(RA).TGP was approved by the China Food and Drug Administration as an antiinflammatory and immune-modulator drug in 1998.Reportedly,TGP has been shown to be safe after long-term clinical use without serious side effects.However,slow effects and low bioavailability limit its clinical applications.Paeoniflorin(Pae),a water-soluble monoterpene glucoside,is the main effective component of TGP(> 40 %).We have previously confirmed that Pae has anti-inflammatory and auto-immune modulative effects.However,Pae is poorly absorbed after oral administration,leading to a very low bioavailability(3% – 4%).Taking these into consideration,a novel chemical compound,paeoniflorin-6′-O-benzene sulfonate(CP-25)was synthesized via esterification in our lab.Expectedly,studies have shown that CP-25 indeed possesses improved anti-inflammatory effects than Pae and the bioavailability of CP-25 was better than Pae(10.6%).Food,gender and disease status are factors that can affect pharmacokinetic profiles of drus.The aim of this study was to investigate the effects of gender,food and adjuvant arthritis(AA)on the pharmacokinetics of CP-25 and its primary metabolite(Pae,M1)after oral administration in the plasma of rats.Objective:1.Food,gender and AA are factors that can affect pharmacokinetic profiles of CP-25 and M1.2.The distribution of CP-25 and Pae in male rats and the distribution of CP-25 in different gender rats were researched.Methods:1.A specific and sensitive ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)assay for rapid determination of CP-25 and Pae in biological sample was developed and validated for the first time.2.The aim of this study was to investigate the effects of gender,food and AA on the pharmacokinetics of CP-25 and M1 after oral administration in rats’ plasma.3.The distribution of CP-25 and Pae in rats was investigated after oral administration.And then,we take out the tissues(e.g.heart,liver,spleen,lung,kidney,intestine,stomach,fat,muscle,brain,salivary gland and synovium).Results:1.In this experiment,there is no interference of endogenous peak areas at retention time of CP-25,Pae and IS(1.84,0.46 and 1.49 min,respectively).The regression equation for calibration curve were y = 0.0056x-0.0122(r2= 0.9990)for CP-25 and y= 0.0049x-0.0148(r2= 0.9990)for Pae respectively.The LLOQ samples(2 ng·mL-1,n=6)were validated with RE within ±10 % and RSD no more than 20 % for each LLOQ sample.The LLOQ of CP-25 in plasma was 2 ng·mL-1.Intra-day precision,inter-day precision,and accuracy for CP-25 and Pae were within the acceptable criteria of ±15 %.The extraction recovery of CP-25 and Pae in rat plasma at three levels of QC samples ranged from 88.5 % to 102.9 % and 99.5 % to 112.4%.The IS(200 ng·mL-1)was 103.0 ± 3.3 %.It is illustrated that the method could meet the requirements of analysis.The matrix effect of CP-25 at three QC concentrations was between 100.9 % and 113.7 % and Pae was between 102.3% and 113.8%.The IS(200ng·mL-1)was 99.7 ± 4.4 %.The CP-25 and Pae was stable in the different storage conditions.2.Effect of gender on pharmacokinetics of CP-25: For CP-25,there are significantdifferences in the parameters of V between female and male after oral administration of 50 mg·kg-1dosages(P < 0.05).The Cmax of the CP-25 reached about 2-3 hours after oral administration.The t1/2α and t1/2β of CP-25 is in the range of 1 to 2 hours and 7 to8 hours at 50 mg·kg-1 dosages.For M1,there are no significant different in the pharmacokinetics parameters between female and male.3.Effect of food on pharmacokinetics of CP-25: There are significant differences in CL(19.51±2.32 L·h·-1kg-1 versus 16.55±0.58 L·h·-1kg-1 for CP-25;23.31±2.58L·h·-1kg-1 versus 16.40±2.92 L·h·-1kg-1 for M1)and AUC(0-∞)(2892.48±89.53 μg·L-1·h versus 3024.34±107.15 μg·L-1·h for CP-25;2166.64±247.61 μg·L-1·h versus3137.30±584.25 μg·L-1·h for M1)between fasted and fed groups after oral administration of CP-25 at a dosage of 50 mg·kg-1(P<0.05).In addition,the values of AUC(0-t)(2062.02±206.48 μg·L-1·h versus 2871.64±409.82 μg·L-1·h)and Cmax(233.36±32.67 μg·L-1versus 322.00±45.22 μg·L-1)were significant differences between fasted and fed groups for M1(P<0.05).No statistical significant differences of other parameters were observed in the study.4.Effect of AA on pharmacokinetics of CP-25: the values of AUC in AA rats was significantly lower than that in normal rats(AUC(0-t),2461.90±168.25 μg·L-1·h versus2727.59 ± 215.01 μg·L-1·h;AUC(0-∞),2685.91±60.97 ug·L-1·h versus 2892.48±89.53ug·L-1·h)(P<0.05).5.Multiple-dosing: the values of AUC and Cmax after multiple-dose of CP-25 was significantly higher than that in single-dose(AUC(0-t),2461.90±168.25 μg·L-1·h versus2856.62±263.54 μg·L-1·h;AUC(0-∞),2685.91±60.97 μg·L-1·h versus 2909.34±302.84μg·L-1·h;Cmax,354.14±23.62 μg·L-1 versus 392.82±10.69 μg·L-1)(P<0.05).Additionally,the values of AUCss,Cav and DF of CP-25 were 2512.02±114.83μg·L-1·h,209.34±9.57 μg·L-1 and 1.88±0.07,respectively.6.Distribution of CP-25 in rats: There are significant different that the CP-25 exist in tissues of different gender rats and have a wide distribution.The concentration of CP-25 in tissues of male rats(e.g.liver,synovium,muscle,intestine and spleen)was highest.Meantime,the concentration in synovium was highest at 3h.Theconcentration of CP-25 in tissues of female rats(e.g.liver,intestine muscle and brain)was highest and other tissues have a certain distribution.In addition,the concentration of CP-25 in tissues was highest than Pae.CP-25 in brain was highest than Pae.Conclusion:1.CP-25 could have more extensive distribution in females than that in male rats but no differences in M1.2.Food intake could also increase the extent of absorption and decrease the rate of clearance of CP-25 and M1 after oral administration in rats.3.The AA would decrease the absorption of CP-25 in rats.4.In male and female rats,CP-25 major exist differences in the liver,lung,brain,synovium and intestine. |
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