氯硝柳胺丙戊酸酯的体外化学稳定性及体内药代动力学初步研究

目的对具有潜在的组蛋白去乙酰化酶和蛋白酪氨酸激酶双重抑制作用的抗肿瘤化合物氯硝柳胺丙戊酸酯进行体外水解动力学、血浆稳定性及体内药代动力学初步研究。方法采用HPLC法研究体外氯硝柳胺丙戊酸酯在不同pH值的水溶液、血浆中的稳定性,以及体内研究大鼠静脉注射10 mg·kg-1氯硝柳胺丙戊酸酯后,测定不同时间点大鼠血浆中的氯硝柳胺丙戊酸酯及氯硝柳胺的浓度,对其血药浓度-时间采用BABP 3.0软件拟合,估算其药动学参数。结果血浆中氯硝柳胺丙戊酸酯、氯硝柳胺在血浆中0.1-100.0 mg·L-1范围内线性关系良好(r=0.9999),回收率>80%和日内及日间精密度<10%;氯硝柳胺丙戊酸酯体外在酸性及中性水溶液中比较稳定,在碱性水溶液中易水解,在体外血浆中水解半衰期为8.5 min;氯硝柳胺丙戊酸酯以10mg·kg-1静脉给药后,氯硝柳胺丙戊酸酯在大鼠体内的T12为(14.25±2.43)min,AUC0-t为(280.6±39.7)min·mg·L-1,氯硝柳胺在大鼠体内的T12为(1.61±0.32)min,AUC0-t为(57.1±20.4)min·mg·L-1。结论氯硝柳胺丙戊酸酯在体外具有一定的稳定性,同时体内能够水解成氯硝柳胺和丙戊酸。

Population pharmacokinetics of paeoniflorin in guanxin Ⅱ prescription

To evaluate the effect of components in Guanxin Ⅱ prescription on the pharmacokinetic profiles of paeoniflorin. Plasma concentration of Paeoniflorin in rats after intravenous injection of Paronia Pall Extract （PPE） and oral administration of PPE and three types of decoctions in Guanxin Ⅱ prescription, respectively, were determined by HPLC analyses. NONMEM （nonlinear mixed-effect modeling） method was used to analyze full set of pharmacokinetic data directly. A two-compartment model with first-order degradation in absorption compartment was employed for the data analysis. The mean of population parameters, CL1, V1, CL2, V2, Ka0, and Kal, were measured to be 0.509 L/h, 0.104 L, 0.113 L/h, 0.123 L, 0.135/h, and 0.0135/h, respectively. Inter-individual variabilities were estimated and dose formulation （DF） was identified as a significant covariate of Ka 1, Ka0, and V1. It is concluded that the pharmacokinetic behaviors of paeoniflorin in rats can alter with different dose formulations.

Pharmacokinetics of Oxiracetam in Healthy Volunteers

Aim To study the pharmacokinetics of oxiracetam after single and multipleintravenous administrations in healthy volunteers. Method A HPLC method was used to determine theserum concentration of oxiracetam after intravenous single dose and daily dose of 2 000 mg for 7 din ten Chinese healthy volunteers. Pharmacokinetic analysis was carried out using Drug And Statisticsoftware. Results The AUC_(0-12), AUC_(0-∞), K_e, t_(1/2), MRT after a single dose of 2 000 mgoxiracetam were 256.26 ± 16.84 μg·mL^(-1)·h, 276.74 ±18.11 μg·mL^(-1)·h, 0.18 ±0.03 h^(-1),3.84±0.64 h, and 4.39 10.39 h, and after multiple doses of oxiracetam were 259.36 ±25.43μg·mL^(-1)·h, 285.59 ±27.38 μg·mL^(-1)·h, 0.17 ±0.04 h^(-1), 4.14 ± 0.82 h, and 4.87 ±0.69 h, respectively. Conclusion The pharmacokinetic parameters of oxiracetam do not differremarkably after single and multiple intravenous administration and there is accumulation in serumafter 2 000 mg multiple intravenous administration once a day fof 7 d.

Pharmacokinetics of Remifentanil in Chinese Patients Undergoing Elective Surgery

Aim To study the pharmacokinetics of remifentanil in Chinese aduh patients undergoing elective surgery and compare the results with the data already published. Methods The pharmacokinetics of remifentanil was determined in 10 aduh patients undergoing elective surgery. Remifentanil 5 - 6 μg·kg^-1 was administered within 1 min after the induction of anesthesia. One point five millilitre of arterial blood samples were collected at 0 （baseline）, 1,2, 3, 5,7, 10, 15, 20, 25, 30, 45, 60, and 90 min after drug administration. Remifentanil concentration was assayed by HPLC/MS/MS. Resuits The concentration-time course of remifentanil was best described by a two-compartment model. Total clearance （CL = 2. 149 ± 0. 431 L·min^-1） of remifentanil was greater than the normal hepatic blood flow. The distribution half-life （t1/2α） [ 1.56 ± 0. 52 min （0.73 - 2.31 ） ] and the elimination half-life （t1/2β） [22.07 ± 10.30 min （9, 71 -36.07）] were similar with those in previous reports. Volume of distribution （ Vd = 65. 766 ± 29. 100 L） was about two times greater than that reported in previous studies of other ethnics. Conclusion In the present study, the volume of distribution is significantly greater than thai reported in previous studies of other ethnics, indicating that there are some differences in the pharmacokinetics of remifentanil among different ethnics.

Determination of Zolmitriptan in Human Plasma by High-Performance Liquid Chromatography-Electrospray Mass Spectrometry and Study on Its Pharmacokinetics

Aim To establish a new and sensitive HPLC-MS method for the determination ofzolmitriptan in human plasma and study the pharmacokinetics of zolmitriptan in healthy volunteers.Methods A single oral dose of 5 mg of zolmitriptan tablet was given to 20 healthy male volunteers.After dosing, blood samples were collected for a period of 24 h, and zolmitriptan concentration inplasma was analyzed by HPLC-MS. Results The plasma concentration-time course fitted well atwo-compartment open model with a lag time, giving the following pharmacokinetic parameters: T_(max)1.60 ± 0.24 h, C_(max) 9.73 ± 1.43 ng·mL^(-1). T_(1/2α)1.72±0.46 h, T_(1/2β) 4.52 + 0.97 h,and AUC_(0-t) 55.59 ± 5.12 ng·mL^(-1)·h. Conclusion The improved analytical method forzolmitriptan is rapid, sensitive and suitable for application to pharmacokinetic studies and routinedetermination of numerous samples.

Preparation and evaluation of ophthalmic thermosensitive in situ gels of penciclovir

Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of HPMC K4M or carbopol 934P and pluronic F127. Optimized formulations were examined through measuring gelation temperature, rheology speciality, drug release behavior, pharmacokinetics and ocular irritation. Results The gelation temperature was reduced by adding HPMC K4M or carbopol 934P, and the viscosity was enhanced slightly. Either HPMC K4M or carbopol 934P delayed the release of PCV from in situ gel. PCV was released by non-Fickian diffusion. The study of ocular irritation for different PCV formulations did not show any irritation or damage for the cornea. PCV bioavailability from combination of carbopol 934P and pluronic F127 gels was higher than that obtained from any other gels. Conclusion Pluronic F127 formulations of PCV can be used as liquid for administration by instilling into the eye. Facilitated by the appropriate eye temperature, the formulations were transformed to gel phase. On the basis of in vitro and in vivo results, PCV formulations containing HPMC K4M or carbopol 934P and low concentration of pluronic F127 （12%） showed potential for use as a drug delivery system with improved ocular bioavailability.

Pharmacokinetics of Ferulic Acid in Rabbits with BloodStasis

To test and study the Syndrome and Treatment Pharmacokinetics (S & TRK),we studied the pharmacokinetics of ferulic acid in healthy and blood stasis (microcirculation dysfunction)rabbits by RP-HPLC. After a single intravenous injection offenilic acid(5mg/kg)to healthy and blood stasis rabbits, compartment model of ferulic acid serum concentration was fitted and then pharmacokinetic parameters were calculated with a MCPKP program on a COMPAQ 386 compute Important parameters are as follows: In healthy rabbits V_B=0.9525±0.0211 L/kg,V_1=0.2462±0.0381 L/kg, CL_B=1.8133±0.9512 L/h·kg, T_(1/2β)=0.3639±0913, AUC=2.7566±0.8232 μg·h/ml; In blood stasis rabbits V_B=0.7882±0.0321 L/kg,V_1=0.1966±0.0537 L/kg,CL_B=0.8820±0.5481 L/h·kg,T_(1/2β)=0.6193±0.1216 h, AUC=5.6690±2.3541μg·h/ml.Through this experiment we found the sig-nificant differences in the FA's pharmacokinetic parameters between healthy and blood stasis rabbits.The results obtained correspond with S & TPK.

High Resolution Determination of Ondansetron in Human Plasma by HPLC and Pharmacokinetics of Orally Disintegrating Tablets

Ahn To develop a high resolution HPLC method for the determination of ondansetron in human plasma and to study the pharmacokinetics of ondansetron in orally disintegrating tablets. Methods HPLC determination involved liquid-liquid extraction, separation on a CN column and ultraviolet detection at 310 ran with granisetron as an internal standard. Pharmacokinetics and bioequivalence of ondansetron in orally disintegrating tablets by direct compression and conventional 8 mg tablets were evaluated and compared in 20 healthy human male volunteers after a single oral dose in a randomized cross-over study. Results The limit of quantification was 0.25 ng· mL^-1. The recovery was about 85 % or over for ondan setron and about 90% for internal standard. Linearity was good within the concentration range of 0.5 - 50 ng·mL^-1 with r^2 ranging from 0.997 1 to 0.999 9. Intra- and inter-assay coefficients of variation ranged from 1.78% to 2.38% and 3.88% -5.19%, respectively. Accuracies for spiked concentrations of 2.0, 10.0, and 30.0 ng·mL^-1 were 104.7% ±4.4%, 102.2% ± 1.1%, and99.51% ±2.34%, respectively. Pharmacokinetic parameters of AUCo-t, AUCo-∞ , Cmax, Tmax, and T1/2 were 230.2 ± 78.0 ng·h·L^-1 , 265.2± 101.5 ng·h·mL^-1, 35.67 ± 8.94 ng·mL^-l, 1.51 ±0.79 h, and 5.00± 1.41 h for orally disintegrating tablets, respectively. The analysis of variance did not show any significant difference between orally disintegrating tablets and conventional tablets, and 90% confidence intervals fell within the acceptable range for bioequivalence. Conclusion High resolution HPLC method has been set up and applied in pharmacokinetic evaluation of ondansetron in orally disintegrating tablets.

Pharmacokinetics of Scutellarin in Dogs

Aim To establish an RP-HPLC method for the determination of scutellarin in plasma and study its pharmacokinetics in dogs. Methods Scutellarin was given to dogs by intravenous injection and determined by RP-HPLC, the mean plasma concentration-time curve was plotted and pharmacokinetic parameters were calculated by program 3p87. Resu;ts The concentration-time curve of scutellarin could be fitted to three-compartment model with T1/2 pi, T1/2 α and T1/2 β being 1.05 ± 0.80 min, 6.99 + 2.76 min and 51.61 + 28.78 min, respectively, Vc being 880.1 + 508.3 mL, CL being 189.6 + 53.8 mL@ min- 1, and AUC0-90 and AUC0-∞ being 574.43 + 133.95 μg@ min@ mL - 1 and 599.34 ± 132.00μg@ min@mL- 1, respectively. Conclusion The fact that the concentrations of scutellarin in plasma declined rapidly after the medication suggested that the T1/2 of scutellarin should be taken into account in drug administration and preparation development.

Preparation and Pharmacokinetic Characterization of Sustained Release Melatonin Tablet

Aim To prepare the sustained release melatonin tablet with HPMC matrix and study its pharmacokinetics and bioavailatility. Methods HPMC was used as matrix to formulate the sustained release tablet. The influences of the size of melatonin, type and amount of HPMC, drug loading, type and amount of additives, and compressing pressure were investigated. Plasma concentration of melatonin in dogs after intravenous injection of two doses and oral administration of sustained release tablets and unmodified release capsules was detected by HPLC using fluorescence detector. Results The drug release from sustained release tablets was influenced by the size of melatonin, type and amount of HPMC, drug loading, and type and amount of additives. Melatonin was found to fit two compartment model after intravenous injection, AUC was proportional to doses, and t(1/2β) of two doses has no significant difference. Relative bioavailability of melatonin sustained release tablet to normal capsule was 83.8%, and absolute bioavailability was 3.75% for sustained release tablet and 4.49% for capsule. Conclusion The melatonin sustained release tablet was well formulated. The absolute bioavilability for oral administration of either sustained release tablet or unmodified release capsule of melatonin was less than 5%. The bioavailability of melatonin sustained release tablet was lower than that of unmodified release capsule, but MRT of sustained release tablet was significantly longer than that of capsule.

Determination of Sulphonylurea Glimepiride in Dog Serum by RP-HPLC with Pre-column Derivatization

Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.

Sensitive liquid chromatography electrospray ionization ion-trap mass spectrometry for the determination of rupatadine in human plasma

Aim To develop and validate a sensitive and specific liquid chromatography electrospray ionization ion-trap mass spectrometry （LC-ESI-MS/MS） method for the identification and concentration of rupatadine in human plasma. Methods After the addition of the internal standard （IS, loratadine） and 0.01 mol·L^-1 sodium hydroxide solution, plasma samples were extracted with methylene chloride： ethyl acetate mixture （20：80, V/V）. The organic layer was evaporated under vacuum drying at 37 ℃. The residue was reconstituted with 200 μL mobile phase. Chromatography was performed on an Agilent Eclipse XDB-C18 （4.6 mm × 150 mm, 5 μm） column with a mobile phase consisting of acetonitrile （1% formic acid） -20 mmol·L^-1 ammonium acetate （76：24, V/V） at a flow-rate of 0.6 mL·min^-1. Detection was performed on Agilent MSD Trap XCT ion-trap mass spectrometry connected to a Agilent 1100 high performance liquid chromatography （HPLC） by selected reaction monitoring （SRM） mode via electrospray ionization （ESI） source. Rupatadine （MRM m/z 416 → 309） and loratadine （MRM m/z 383 → 337） were detected by Agilent MSD Trap XCT ion-trap mass analyser. Results The method was proved to be sensitive and specific by testing 20 different plasma batches. Linearity was established for the range of concentrations 0.05 - 14.0 ng·mL^ -1 with a coefficient of determination （r） of 0.998. The intra-and inter-day precision （RSD %） were lower than 15% and accuracy ranged from 85.1% to 114.0%. The lower limit of quantitation （LLOQ） was identifiable and reproducible at 0.05 ng·mL^-1 with a precision of 9.22% （n =5）. Conclusion The proposed method is sensitive and reproducible enough to be used in pharmacokinetic, bioavailability or bioequivalence studies of rupatadine.

Pharmacokinetics of Active Metabolite of Prulifloxacin in Healthy Chinese

Aim To investigate the pharmacokinetics of NM394 （an active metabolite of prulifloxacin） and evaluate the dose relationship and accumulation characteristics after single and multiple doses of prulifloxacin. Methods Twelve healthy volunteers were given 132.1 mg, 264.2 mg, and 396.3 mg of prulifloxacin tablets in a randomized 3 × 3 crossover design test for single doses trial. With one-week washout period, 264.2 mg of prulifloxacin tablets were given for multiple doses trial. NM394 in plasma was determined by a sensitive HPLC method and its pharmacokinetic parameters were analyzed and evaluated by Drug and Statistics saftware （version 1.0）. Results The Cmax, Tmax, t 1/2, AUC0-24, and AUC0-∞ of NM394 after single doses of 132.1 mg, 264.2 mg, and 396.3 mg of prulifloxacin tablets were 0.64 ± 0.25 μg· mL^-1, 1.06 ± 0.35 μg· mL^-1, and 1.45 ± 0.44 μg· mL^-1 , respectively; Tmax 0.94±0.22 h, 1.02±0.17 h, and 0.98±0.23 h, respectively; t 1/2 8.37±0.70 h, 7.70±0.82 h, and 7.78 ± 0.77 h, respectively; AUC0-24 2.93 ± 0.78 μg· mL^-1· h, 4.39 ± 1.05 μg· mL^-1· h, and 5.55± 1.32 μg·mL^-1 ·h, respectively; AUC0-∞ 3.32±0.84 μg·mL^-1 ·h, 4.82± 1.06 μg·mL^-1 ·h, and 6.10 ± 1.38 μg·mL^-1· h, respectively. And the Cmax, Tmax, t,1/2, AUC0- 24, and AUC0-∞ after multiple doses of 264.4 mg prulifloxacin tablets were 1.20 ± 0.33 μg· mL^- 1, 0.67 ± 0.12 h, 7.38 ± 1.03 h, 5.58 ± 1.25 μg· mL^-1·h, and 6.09 ± 1.24 μg· mL^-1· h, respectively. Conclusion The Cmax and AUC of NM394 are in high correlation with given prulifloxacin doses. There are no differences in pharnacokinetic characteristics of NM394 between single and multiple doses. No accumulation in plasma is observed after multiple doses of 264.2 mg per day for 7 d.

Pharmacokinetics of Native r-SAK in Rabbit's Femoral Artery Thrombosis Model

Objective: To study the pharmacokinetics of native r SAK in rabbit's femoral artery thrombosis model, the “lytic circle' method was used to determine plasma levels of r SAK. Methods: Thirty New Zealand rabbits were randomly assigned to the control (saline 10 ml, 30 min), r SAK low dose (0.25 mg/kg, 30 min), medial dose (0.50 mg/kg, 30 min), high dose (1.00 mg/kg, 30 min), single bolus (0.50 mg/kg, 2 min) and conjunctive therapy (initiated with heparin 200 U/kg, followed by infusion of r SAK 0.50 mg/kg for 30 min, and subsequently infused heparin 50 U/(kg·h) to endpoint) groups. The right femoral artery thrombosis model in rabbit was made by balloon injury, then the thrombolytic agents were infused through parallel ear vein and the blood samples were collected pre thrombolysis and at different time post thrombolysis to determine the plasma levels of r SAK by “lytic circle' method, the plasma levels of r SAK were processed by pharmacokinetic computing procedure to fit the model. Results: The plasma levels of r SAK and the diameters of lytic circles showed a pretty good linear correlation under the scope of 2.0×10 4 2.0×10 6 U/L, and the averaged recycle rate was (96.05±11.35)%(RSD =±11.82%).All peak concentration time in each infusion group was 30 min, and the peak concentrations positively correlated with the doses administrated in infusion groups(r=0.999 98, P <0.000 1). In single bolus group, Peak concentration time was 2 min, and the peak concentration reached (5.16±1.02) mg/L, which was significant higher than that in the same dose r SAK infusion group ( P <0.01). In conjunctive therapy group, the peak concentration showed no significant difference from that in the same dose r SAK infusion group ( P >0.05). The plasma levels of r SAK fit in two compartment model as processed by pharmacokinetic computing procedure in each group. Conclusion: The “lytic circle' method is a simple, practical and reliable method to determine the plasma level of r SAK, and the pharmacokinetics of native r SAK infusion fits in two compartment model in rabbit's femoral artery thrombosis model.

Determination of fleroxacin in human plasma by HPLC with fluorescence detection and the pharmacokinetic study

Aim To develop a sensitive and accurate HPLC method for the determination of fleroxacin in human plasma, and study its pharmacokinetics in healthy subjects. Methods The analytes were isolated fi＇om plasma by simple protein precipitation with methanol, separated on a Diamonsil C18 column by isocratic elution with the mobile phase consisted of 1% triethylamine at pH 4.8 （adjusted with phosphoric acid） and acetonitrile （80/20, V/V） at a flow rate of 1.0 mL.min^-1 and analyzed by fluorescence detector with an excitation at 290 nm and emission 458 nm. The pharmacokinetic study of fleroxacin was performed according to a double period crossover design. Results The weighted （1/x） calibration curve was linear over the plasma concentration range of 0.025 - 8.00 μg.mL^-1 The inter- and intra-day precisions （RSD/%） were no more than 5.16%, and the method accuracies and extraction recoveries at three concentrations ranged firom 99.1% to 100.9%, and 86.7% to 92.0%, respectively. Following oral administration at a dose of 400 mg fleroxacin, the main pharmacokinetic parameters for test and reference capsules were Cmax5.08 ± 0.78 and 5.38 ± 1.40 μg.mL^-1, tmax 1.72 ±0.79 and 1.82 ± 0.78 h, t1/2 11.68 ± 1.27 and 11.38 ± 1.51 h^-1, AUC0-∞ 78.44 ± 11.44 and 76.53 ± 13.24 μg.mL^-1.h, respectively. Conclusion The method is sensitive and accurate, and suitable for human pharmacokinetic study of fleroxacin.

Pharmacokinetic-Pharmacodynamic Studies on Propra-nolol and 4-Hydroxypropranolol

The pharmacokinetic-pharmacodynamics of propranolol (PPL) and its activemetabolite 4-hydroxypropranolol (4-OH-P) was studied on Chinese subJects by single or multipleoral administration. The efficiency of beta-blockade was measured as the reduction of heart rates orblood pressure in the supine and upnght positions during rest or exercise period. After a single doseof 40 mg PPL, the plasma concentration of 4-OH-P was quite high, C (m) max and AUC (m) were26. 1±13.2 ng/ml and 180±69 ng.h/ml respectively, which were 50% and 73% of those of PPL.Whileafter multiple dose administration, the plasma PPL concentration increased much greater than that insingle administration and the 4-OH-P/PPL plasma level ratio fell from 0.79±0.64 at single dose toonly 0.48±0.32 at steady-state. The pharmacodynamic half-life of PPL on inbibiting exercising heart-rate was much longer than the halflife of drug concentration (8.78±2.27 vs 4.23±1.33 h. P<0.0 1).The Css 50. plasma concentration at steady-state producing 50% maximal efficacy, was 44.66±35.24ng/ml. The study showed that 4-OH-P is an important active metabolite of PPL and one of thepossible factors causing the considering variations in the response to PPL in Chinese people.

Pharmacokinetics of Moclobemide Sustained Release Tablets after Multiple Oral Dose Administration in Healthy Volunteers

To investigate the pharmacokinetic characteristics of moclobemide sustainedrelease tablets after multiple oral dose administration in healthy Chinese volunteers. MethodsMoclobemide sustained release tablets were given as a multiple oral dose regimen of 300 mg oncedaily for five consecutive days to 12 healthy volunteers. The concentrations of moclobemide inplasma were determined by reversed-phase high performance liquid chromatography. The partialpharmacokinetic parameters were calculated using 3p97 pharmacokinetic program. Results Theconcentration-time profile fitted an one-compartment model best. The steady-state pharmacokineticparameters of moclobemide sustained release tablets after multiple oral doses were as follows:C_(max) was (1 950 +- 156) μg· L^(-1), T_(max) was (6.00 +-1.55) h, T_(1/2(kel)) was (3.14 +-0.12)h, AUC_(ss 0-24) was (22 836 +- 1 842) μg·h· L^(-1), MRT was (7.68+-0.36) h, CL/F_((s)) was(20.2+-2.1) L·h^(-1), and V/F_((c)) was (91.4+-9.4) L, respectively. No marked adverse events werenoted during this study. Conclusion The formulation has a sustained-release effect and goodtolerance in the healthy volunteers, which provides useful information for clinical practice.

Pharmacokinetics of 20(R)-Ginsenoside Rg3 in Human Volunteers

Objective: To study the pharmacokinetics of 20(R)-Ginsenoside Rg3 in the human body. Methods: High-performance liquid chromatography-ultraviolet detection method was used in this study. Results: The pharmacokinetics of Ginsenoside Rg3 in 14 healthy volunteers were investigated. After a single oral dose of 3.2 mg.g-1 Ginsenoside Rg3 in 8 male volunteers, the plasma concentration-time course fitted in well with a two-compartment open model, with the following pharmacokinetic parameters: Tmax 0.660.10 h, Cmax 166 ngmL-1, T1/2a 0.460.12 h, T1/2b 4.91.1 h, T1/2(Ka) 0.280.04 h, AUC0-∞ 7726 ngmL-1h, respectively. No kinetic analysis was made after an oral dose of 0.8 mg.g-1 Rg3 in other 6 volunteers because of the low concentration, but there was a good correlation between Cmax and dosage of the two groups. Conclusion: The absorption of Rg3 was rapid in the human body, and its elimination was rapid too after oral administration of Ginsenoside Rg3. The pharmacokinetic results shows that it exhibited the first-order kinetic characteristics.

Determination of Diphenytriazol (DL111-IT) in Rabbit Plasma by High-Performance Liquid Chromatography with Fluorescence Detection

Aim To develop an HPLC method with fluorescence detection for the assay ofDL111-IT in rabbit plasma. Methods DL111-IT and internal standard glybenzcyclamide in rabbit plasmawere extracted with chloroform. The determination was performed on a Diamonsil ODS-C_(18) column(150 mm x 4.6 mm, 5 μm) with a mobile phase of acetonitrile and 0.025 mol·L^(-1) diammoniumhydrogen phosphate buffer (pH 5.0, adjusted by phosphoric acid) (60:40, V/V) at a flow-rate of 1.0mL·min^(-1) . Fluorescence detector was operated at excitation wavelength of 250 nm and emissionwavelength of 332 nm. Results The calibration curve in plasma was linear from 1.00 - 20.00ng·mL^(-1) ( r = 0.999 6, n = 5). The method afforded average extracting recoveries of 85.3% ±1.3%, 84.9% ± 2.7% and 85.8% ± 1.8%, and the average method recoveries were 99.5% ±0.4%, 102.1%± 1.8% and 101.3% ± 2.4% for the high (20.00 ng·mL^(-1)) , middle (10.00 ng·mL^(-1)) and low (1.00 ng·mL^(-1)) check samples, respectively. The intra-day (n = 5) and inter-day (n = 5) precisions(RSD) were less than 3.0% and 7.0%, respectively. The limit of detection and quantitation for themethod were 0.3 ng·mL^(-1) (S/N = 3) and 1 ng·mL^(-1) (S/N = 10, RSD<7.0%) plasma sample,respectively. Conclusion The developed method was accurate, sensitive, simple and could be used forpharmacokinetic study of DL111- IT.