Determination and pharmacokinetic study of syringin and chlorogenic acid in rat plasma after administration of Aidi lyophilizer

A high-performance liquid chromatographic (HPLC) method was developed for the first time to simultaneously quantify syringin and chlorogenic acid in rat plasma using wavelength-transfer technology. The analysis was performed on a Diamonsil C(18) column (200 x 4.6 mm i.d., 5 microm particle size) with isocratic mobile phase consisting of acetonitrile-0.05% phosphoric acid (12:88, v/v). The linear ranges were 0.20-10 and 0.25-30 microg/mL, respectively. The lower limits of quantification were 0.20 and 0.25 microg/mL, respectively. The method was shown to be reproducible and reliable with intraday precision below 8.5 and 6.1%, interday precision below 7.1 and 5.5%, accuracy within +/-7.1 and +/-8.6%, and mean extraction recovery excess of 92.1 and 80.9%, respectively, which were all calculated from the blank plasma sample spiked with syringin and chlorogenic acid at three concentrations of 0.20, 1.0 and 6.0 microg/mL for syringin and 0.25, 2.0 and 20 microg/mL for chlorogenic acid. This method was validated for specificity, accuracy and precision and was successfully applied to the pharmacokinetic study of syringin and chlorogenic acid in rat plasma after intravenous administration of Aidi lyophilizer.     

HPLC analysis and pharmacokinetics of icariin in rats

As a prerequisite to the determination of pharmacokinetic parameters of icariin in rats, an HPLC method using UV detection was developed and validated. Icariin and the internal standard, quercetin, were extracted from plasma samples using ethyl acetate after acidification with 0.05 mol/L NaH2PO4 solution (pH 5.0). Chromatographic separation was achieved on an Agilent XDB Cls column (250 x 4.6 mm id, 5 microm) equipped with a Shim-pack GVP-ODS C18 guard column (10 x 4.6 mm id, 5 microm) using a mobile phase of ACN/water/acetic acid (31:69:0.4 v/v/v) at a flow rate of 1.0 mL/ min. Detection was at 277 nm. The calibration curve was linear from 0.05 to 100.0 microg/mL with 0.05 microg/mL as the lower LOQ (LLOQ) in plasma. The intra- and interday precisions in terms of RSD were lower than 5.7 and 7.8% in rat plasma, respectively. The accuracy in terms of relative error (RE) ranged from -1.6 to 3.2%. The extraction recoveries of icariin and quercetin were 87.6 and 80.1%, respectively. The main pharmacokinetic parameters for rats were determined after a single intravenous administration of 10 mg/kg icariin: t1/2, 0.562 +/- 0.200 h; AUC0-infinity, 8.73 +/- 2.23 microg x h/mL; CLToT, 20.10 +/- 5.80 L/kg x h; Vz, 1.037 +/- 0.631 L/kg; MRT0-infinity, 0.134 +/- 0.040 h; and Vss, 0.170 +/- 0.097 L/kg.     

Determination of picroside II in dog plasma by HPLC and its application in a pharmacokinetics study

A sensitive and simple high-performance liquid chromatography method with UV detection was developed and validated for determining picroside II in dog plasma. Paeoniflorin was employed as internal standard and the sample pre-treatment procedure consists of deproteinization by addition of acetonitrile. Chromatographic separations were performed on a Shimadzu VP-ODS column (250 x 4.6 mm i.d., 5 microm). The mobile phase consisted of acetonitrile-0.1% acetic acid aqueous (v/v), 23:77, v/v, at a rate of 1 mL/min. Detection was carried out at a wavelength of 266 nm. Calibration standards ranged from 0.25 to 500 microg/mL in dog plasma and the mean correlation coefficient of 0.9981 was found for the linear calibration curves (n = 6). The limit of quantification (LOQ) was 0.25 microg/mL. Intra- and inter-assay RSD ranged from 0.70 to 7.5%. Accuracy (%bias) ranged from -6.3 to 6.0%. This method was applied to the pharmacokinetic study of picroside II in dogs. The study demonstrated the plasma picroside II concentration-time curves were fitted to the two-compartment open model and showed linear pharmacokinetics.     

A high-performance liquid chromatographic method for saikosaponin a quantification in rat plasma

A high-performance liquid chromatographic method with UV detection has been developed for the determination of saikosaponin a in rat plasma. Saikosaponin a and internal standard jujuboside A were isolated from plasma samples by solid-phase extraction. The chromatographic separation was achieved on a reversed-phase C(18) column with the mobile phase of acetonitrile-water (35:65, v/v) at a flow rate of 1 mL/min and UV detection was set at 205 nm. The standard curve for saikosaponin a was linear over the concentration range 0.25-10 microg/mL and the limit of detection was 0.05 microg/mL. The absolute recovery was greater than 82%. The precision and accuracy ranged from 3.05 to 9.59% and 95.61 to 110.00%, respectively. The validated method was used to determine saikosaponin a in plasma samples in a pharmacokinetic study of saikosaponin a administered to Sprague-Dawley rats.     

Development and validation of a simple and rapid HPLC method for the quantitative determination of voriconazole in rat and beagle dog plasma

A simple and rapid high-performance liquid chromatographic method with UV detection is developed and validated to determine the concentration of voriconazole in rat and beagle dog plasma. After protein precipitation using acetonitrile, the supernatant solution is chromatographed on a Diamonsil C(18) column (250 x 4.6-mm i.d., 5 microm). The mobile phase used is a combination of acetonitrile-water-acetic acid (55:45:0.25, v/v/v) with a pH of 4.0. Detection is achieved by a UV detector monitored at a wavelength of 256 nm. The matrix calibration curves are obtained both in the concentration range of 0.10-50.0 microg/mL in rat and beagle dog plasma, with the lower limit of quantitation of 0.10 microg/mL. The intra- and inter-assay precisions in terms of % relative standard deviation are lower than 8.6% and 6.0% in rat and beagle dog plasma, respectively. The accuracy in terms of % relative error ranged from -0.5% to 8.0% and -0.5% to 6.0% in rat and beagle dog plasma, respectively. This validated method is successfully applied to determine the concentration of voriconazole in plasma after intravenous administration of 36 mg/kg voriconazole to rats and 10 mg/kg voriconazole to beagle dogs, respectively.     

HPLC analysis and pharmacokinetic study of quercitrin and isoquercitrin in rat plasma after administration of Hypericum japonicum thunb. extract

A simple HPLC method was developed for determination of quercitrin and isoquercitrin in rat plasma. Reversed-phase HPLC was employed for the quantitative analysis using kaempferol-3-O-beta-D-glucopyranoside-7-O-alpha-L-rhamnoside as an internal standard. Following extraction from the plasma samples with ethyl acetate-isopropanol (95:5, v/v), these two compounds were successfully separated on a Luna C(18) column (250 x 4.6 mm, 5 microm) with isocratic elution of acetonitrile-0.5% aqueous acetic acid (17:83, v/v) as the mobile phase. The flow-rate was set at 1 mL/min and the eluent was detected at 350 nm for both quercitrin and isoquercitrin. The method was linear over the studied ranges of 50-6000 and 50-5000 ng/mL for quercitrin and isoquercitrin, respectively. The intra- and inter-day precisions of the analysis were better than 13.1 and 13.2%, respectively. The lower limits of quantitation for quercitrin and isoquercitrin in plasma were both of 50 ng/mL. The mean extraction recoveries were 73 and 61% for quercitrin and isoquercitrin, respectively. The validated method was successfully applied to pharmacokinetic studies of the two analytes in rat plasma after the oral administration of Hypericum japonicum thunb. ethanol extract.     

Simultaneous determination of ZLR-8 and its active metabolite diclofenac in dog plasma by high-performance liquid chromatography

ZLR-8 is a nitric oxide releasing derivative of diclofenac for the treatment of inflammation. In this paper, a sensitive and reliable high-performance liquid chromatography method for simultaneous determination of ZLR-8 and its active metabolite diclofenac in the plasma of beagle dogs has been developed and validated. After the addition of ketoprofen as the internal standard (IS), plasma samples were extracted with n-hexane-isopropanol (95:5, v/v) mixture solution and separated by HPLC on a reversed-phase C(18) column with a mobile phase of gradient procedure. Analytes were determined by the UV detector which was set at 280 nm. The method was proved to be sensitive and specific by testing six different plasma batches. Calibration curves of ZLR-8 and diclofenac were linear over the range 0.05-4.0 microg/mL. The within- and between-batch precisions (RSD%) were lower than 10% and accuracy ranged from 85 to 115%. The lower limit of quantification was identifiable and reproducible at 0.05 microg/mL. The proposed method has been readily implemented in preclinical pharmacokinetics studies of ZLR-8 and its active metabolite diclofeance. Representative plasma concentration vs time profiles resulting from administration of ZLR-8 to beagle dogs are presented in this communication.     

HPLC determination and pharmacokinetic study of tenatoprazole in dog plasma after oral administration of enteric-coated capsule

A simple, sensitive and selective high-performance liquid chromatographic (HPLC) method with UV detection (306 nm) was developed and validated for determination of tenatoprazole, a novel proton-pump inhibitor, in dog plasma. Tenatoprazole and internal standard (pantoprazole) were extracted into diethyl ether and separated using an isocratic mobile phase of 10 mm phosphate buffer (pH4.7)-acetonitrile (70:30, v/v) on a Diamonsil C(18) column (150 x 4.6 mm, 5 microm). The retention times for tenatoprazole and internal standard were 7.1 and 12.3 min, respectively. No endogenous interferences were observed. This HPLC method was fully validated. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 20%. A linear range of 0.02-5.0 microg/mL was established. The interday and intraday precisions were within RSD 13.4-10.1 and 4.6-1.4%, respectively. This method developed can be easily applied to the pharmacokinetic study of tenatoprazole in dog plasma after oral administration of an enteric-coated capsule. The plasma concentration of tenatoprazole from six dogs showed a mean C(max) of 2.63 microg/mL at T(max) of 1.89 h. The bioavailability of tenatoprazole was improved by administration of enteric-coated capsule.     

Determination and pharmacokinetic study of bergenin in rat plasma by RP-HPLC method

A validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the determination of bergenin in rat plasma. Bergenin in rat plasma was extracted with methanol, which also acted as a deproteinization agent. Chromatographic separation of bergenin was performed on a C(18) column, with a mobile phase of methanol-water (22:78, v/v) at a flow-rate of 0.8 mL/min and an operating temperature of 40 degrees C, and UV detection was set at 220 nm. The calibration curve was linear over the range 0.25-50 microg/mL (r = 0.9990) in rat plasma. The limit of quantification was 0.25 microg/mL using a plasma sample of 100 microL. The extraction recoveries were 83.40 +/- 6.02, 81.49 +/- 2.40 and 72.51 +/- 2.64% at concentrations of 0.5, 5 and 50 microg/mL, respectively. The intra-day and inter-day precision and accuracy were validated by relative standard deviation (RSD%) and relative error (RE%), which were in the ranges 3.74-9.91 and -1.6-8.0%. After intravenous administration to rats at the dose of 11.25 mg/kg, the plasma concentration-time curve of bergenin was best conformed to a two-compartment open model. The main pharmacokinetic parameters indicated that bergenin exhibited a wide distribution and moderate elimination velocity in rat.     

HPLC determination and pharmacokinetics of osthole in rat plasma after oral administration of Fructus Cnidii extract

A simple and sensitive high-performance liquid chromatographic (HPLC) method is developed for the determination of osthole in rat plasma and applied to a pharmacokinetic study in rats after administration of Fructus Cnidii extract. After addition of fluocinonide as an internal standard, plasma samples are extracted with diethyl ether. HPLC analysis of the extracts is performed on a Hypersil ODS2 analytical column, using methanol-0.4% acetic acid (65:35, v/v) as the mobile phase. The UV detector is set at 322 nm. The standard curve is linear over the range 0.0520-5.20 microg/mL (r = 0.9979). The mean extraction recoveries of osthole at three concentrations were 81.0%, 91.2%, and 90.7%, respectively. The intra- and interday precisions have relative standard deviations from 1.9% to 4.9%. The limit of quantitation is 0.0520 microg/mL. The HPLC method developed can easily be applied to the determination and pharmacokinetic study of osthole in rat plasma after the animals are given the Fructus Cnidii extract. The plasma concentration of osthole from six rats showed a Cmax of 0.776 +/- 0.069 microg/mL at Tmax of 1.0 +/- 0.3 h.     

高效液相色谱法测定大鼠血浆中的原儿茶酸

建立了大鼠血浆中原儿茶酸含量测定的高效液相色谱方法。采用的色谱柱为DiamondsilTM C18 柱(150 mm×4.6 mm,5 μm);流动相为乙腈-水(体积比为9∶91,用H3PO4 调pH至2.5);流速1.2 mL/min;检测波长260 nm;内标为对羟基苯甲酸。原儿茶酸的线性范围为0.050~3.20 mg/L,线性相关系数为0.9978，最低定量限为0.050 mg/L,日内和日间测定的精密度（以相对标准偏差表示）均低于7.0%,准确度（以相对误差表示）为-1.4%～2.6%；在0.050,0.40,3.20 mg/L低、中、高3个添加浓度水平下，血浆样品的提取回收率分别为83.4%,87.3%,91.1%。该方法简便,灵敏,准确,适用于大鼠体内原儿茶酸的药物动力学研究。     

High-performance liquid chromatographic method for the determination and pharmacokinetic study of wogonoside in rat serum after oral administration of traditional Chinese medicinal preparation Huang-Lian-Jie-Du decoction

A high-performance liquid chromatographic method for the determination of wogonoside in plasma of rats administrated orally with the traditional Chinese medicinal preparation Huang-Lian-Jie-Du decoction was developed. Sample preparation was carried out by protein precipitation with a mixture of acetonitrile and methanol (1:1, v/v). The extracted sample was separated on a Hypersil C(18) (150 x 5 mm i.d., 5 microm) analytical column by linear gradient elution using 0.05% (v/v) phosphoric acid (containing 5 mm sodium dihydrogen phosphate) and acetonitrile as mobile phase at a flow rate of 1.5 mL/min. The eluate was detected using a UV detector at 276 nm. The assay was linear over the range 0.109-7.0 microg/mL (R(2) = 0.9999, n = 5). Mean recovery was determined as 98.39%. Intra- and inter-day precisions (RSD) were < or =7.59%. The limit of quantitation was 0.109 microg/mL. After validation, the HPLC method developed was applied to investigate the preliminary pharmacokinetics of wogonoside in rat after oral administration of Huang-Lian-Jie-Du decoction.     

HPLC assay for determination of amphotericin B in biological samples

A fast and selective HPLC method for assaying amphotericin B in biological samples was developed and validated. The chromatographic separation was achieved in less than 12 min on a reverse-phase C(18) column using an acetonitrile-acetic acid-water (52:4.3:43.7, v/v/v) mixture as mobile phase. The flow rate was 1 mL/min and the effluent was monitored at 406 nm. A linear response over the concentration range 0.1-10.0 microg/mL was obtained. Intra-day and inter-day RSDs were below 5% for all the sample types. This new HPLC method was applied to assay amphotericin B in plasma and several tissue samples such as kidney, liver, spleen and bone marrow. Application of this method to pharmacokinetic studies in mice and dog is provided.     

Establishment of a HPLC method for preclinical pharmacokinetic study of the novel anti-Parkinson's disease candidate drug FLZ in rats

An HPLC method was established and validated for the determination of compound FLZ, a synthetic novel anti-Parkinson's disease candidate drug, in rat plasma. FLZ and the internal standard bicyclol were extracted from plasma by solid-phase extraction method and analyzed on a Restek C18 column (4.6 x 250 mm, 5 microm) with a mobile phase consisting of methanol and water (60:40, v/v) at a flow rate of 1.0 mL/min. The detection wavelength was set at 320 nm. The calibration curve was linear within the concentration range from 25 to 500 ng/mL (r2 > 0.999), the limit of quantitation was 25 ng/mL and the average recovery was 92.0% with the RSD less than 5.9%. The relative standard deviation for intra- and inter-day precision was less than 3.8 and 6.9%, respectively. The established HPLC method was validated to be a simple, rapid and reliable procedure and applied to study the preclinical pharmacokinetics of FLZ in rat plasma, and it was the first time that the pharmacokinetics of FLZ had been investigated.     

Determination of calycosin-7-O-beta-D-glucopyranoside in rat plasma and urine by HPLC

A reversed-phase high-performance liquid chromatographic (HPLC) assay for calycosin-7-O-beta-D-glucopyranoside in rat plasma and urine with solid-phase extraction (SPE) was developed. Rutin was employed as an internal standard. The mobile phase consisted of acetonitrile-water (16:84, v/v) at a flow rate of 1.0 mL/min. Detection was set at 280 nm. The limit of quantitation of calycosin-7-O-beta-D-glucopyranoside was 0.2 microg/mL in both plasma and urine. The standard curve was linear from 0.2 to 10.0 microg/mL in plasma, and 0.2 to 5.0 microg/mL in urine. Both intra- and inter-day precision of the calycosin-7-O-beta-d-glucopyranoside were determined and their RSD did not exceed 10%. The method was successfully applied to the analysis of samples obtained from a basic pharmacokinetic study, in which calycosin-7-O-beta-d-glucopyranoside was administered orally to rats.     

Simple determination of pirfenidone in rat plasma via high-performance liquid chromatography

A simple, rapid and reliable high-performance liquid chromatographic method was developed and validated for the determination of pirfenidone and its major metabolites in rat plasma. Plasma proteins were precipitated with perchloric acid (10%, v/v) and the supernatant after centrifugation was determined using high-performance liquid chromatography. The analysis was carried out on a Lichrospher C(18) column (250 x 4.6 mm i.d., 5 microm). The mobile phase consisted of acetonitrile-water containing 0.2% acetic acid (23:77, v/v) at a flow-rate of 1 mL/min. The eluant was detected at 310 nm. The calibration curves were linear over a concentration range from 0.15 to 76.67 microg/mL. The accuracy (relative error) of the assay ranged from -2.6 to 7.9% and the precision (coefficient of variation) was less than 4.5%. The established method has been successfully applied to a pharmacokinetic study of pirfenidone following a single oral dose to rats.     

Simultaneous determination of rifampicin and sulbactam in mouse plasma by high-performance liquid chromatography

A simple and rapid high-performance liquid chromatographic (HPLC) method with ultraviolet detection has been developed and validated for the simultaneous determination of rifampicin and sulbactam in mouse plasma. Plasma samples were deproteinized with acetonitrile and separated by HPLC on a RP-18 (125 x 4 mm, 5 microm) column and gradient elution with potassium dihydrogen phosphate solution (pH 4.5; 50 mm) and acetonitrile at a flow-rate of 1.0 mL/min. Rifampicin and sulbactam were monitored at 230 nm and confirmed by means of their UV spectra using a diode-array detector. The method was linear at plasma levels from 1 to 100 microg/mL for rifampicin and from 5 to 200 microg/mL for sulbactam. The limits of quantification were 0.6 microg/mL for rifampicin and 4.2 microg/mL for sulbactam. The intra- and inter-day precisions of the method (RSD) were lower than 5% for both compounds. Average recoveries of rifampicin and sulbactam from mice plasma were 98.2 and 89.3%, respectively. The developed method was successfully applied to the determination of the pharmacokinetic profile of both compounds in mice.     

Determination of gambogic acid in dog plasma by high-performance liquid chromatography for a pharmacokinetic study

A rapid, simple and sensitive high-performance liquid chromatography method for the quantification of gambogic acid in dog plasma was developed and validated. After acidification with hydrochloric acid, dog plasma was extracted with ethyl acetate and determined by HPLC. The analysis was carried out on a reversed-phase C(18) analytical column. The mobile phase consisted of a mixture of methanol-0.05% phosphoric acid (94:6, v/v), and the column temperature was maintained at 35 degrees C. A constant mobile phase flow rate of 1.0 mL/min was employed throughout the analyses. The ultraviolet detector was set at 360 nm. Chromatographic separation was achieved in less than 10 min and the calibration curve was linear over a concentration range of 0.156-20 microg/mL. The intra-assay and inter-assay variability values were less than 10.0%. The accuracy ranged from 93.0 to 104.2%. The established method has been successfully applied to a pharmacokinetic study of gambogic acid in dogs.     

Validation of a simple HPLC method for assay of haplamine and its metabolites in plasma suitable for pharmacokinetic application in rats

A simple HPLC method with ultraviolet detection has been developed and validated for the simultaneous determination of haplamine and its metabolites (trans/cis-3,4-dihydroxyhaplamine) in rat. A liquid-liquid extraction was used to extract the compounds from rat plasma. The analysis was performed on a C(18) Nucleosil Nautilus column. The mobile phase consisted of water (A) and a mixture of methanol and acetonitrile (85:15; v/v) (B) used in gradient mode (38-40% B for 10 min, 40-58% B for 49 min, 58-38% B for 1 min, and 38% for 5 min) pumped at 1 mL/min. The calibration curves showed good linearity with correlation coefficients greater than 0.999 for the analytes in the investigated concentration range. The lower limit of detection was 0.007, 0.008 and 0.009 microg/mL and the lower limit of quantification was 0.014, 0.017 and 0.018 microg/mL for haplamine, and trans/cis-3,4-dihydroxyhaplamine, respectively. The method was applied to a preliminary pharmacokinetic study in rats. This method proved to meet fully the standards required of experimental pharmacokinetic studies and should be used in further preclinical investigation.