High-performance liquid chromatographic analysis of resveratrol analog 3,5,4'-trimethoxystilbene in rat plasma

(E)-3,5,4'-Trimethoxystilbene (BTM-0512), the analog of resveratrol, is potentially useful for the treatment of human diseases. This is the first study to use high-performance liquid chromatography (HPLC) for the determination of the resveratrol analog in rat plasma. Plasma proteins (0.1 mL) were precipitated with acetonitrile after the addition of the internal standard chlorzoxazone. The analysis used a BDS HYPERSIL C(18) analytical column (5 microm, 4.6 x 250 mm) with acetonitrile/water as the mobile phase. The UV-detection wavelength was 303 nm. The calibration curve was linear over the range of 0.025-10 microg/mL with a correlation coefficient of 0.9958. This concentration range corresponds well with the plasma concentrations of BTM-0512 in pharmacokinetic studies. There was a recovery of 102.2%, 95.3% and 103.7% from 0.05, 5 and 10 microg/mL plasma samples, respectively. The relative standard deviation of intra- and interday assay variations was all less than 13%. This HPLC assay is a quick, precise and reliable method for the analysis of BTM-0512 in pharmacokinetic studies.     

Validation of rapid and simple LC-MS/MS method for determination of voriconazole in rat plasma

A rapid, simple and sensitive LC-MS/MS analytical method was developed and validated for the determination of voriconazole (VRC) in rat plasma, using ketoconazole as internal standard (IS). Analysis was performed on a Shimadzu HPLC system using a Shimadzu C18 column and isocratic elution with acetonitrile-water-formic acid (60:40:0.05, v/v/v), at a flow of 1.0 mL/min (split ratio 1:5), and a mass spectrometer Micromass, equipped with a double quadrupole and an electrospray ionization interface, operated in a positive mode. Plasma samples were deproteinized with methanol (1:2) and 30 microL of the supernatant was injected into the system. The retention times of VRC and IS were approximately 3.3 and 2.7 min, respectively. Calibration curves in spiked plasma were linear over the concentration range of 50-2500 ng/mL with determination coefficient >0.98. The lower limit of quantification was 50 ng/mL. The accuracy of the method was within 5%. Intra- and inter-day relative standard deviations were less or equal to 12.5 and 7.7%, respectively. The applicability of the LC-MS-MS method for pharmacokinetic studies was tested using plasma samples obtained after intravenous administration of VRC to male Wistar rats. The reported method provided the necessary sensitivity, linearity, precision, accuracy, and specificity to allow the determination of VRC in pre-clinical pharmacokinetic studies.     

HPLC法测定人血浆中氨苄青霉素浓度

本文采用HPLC法测定血浆中氨苄青霉素的浓度,采用Spherisorb ODS柱,流动相为PB(0.05mol/L,pH=4.0):乙腈(78:22V/v),标准曲线范围0.22~13.89μg/ml,r=0.9997,保留时间为7.3min,回收率试验大于95%,日内和日间变异(RSD%),小于7%,最小检测浓度为0.22μg/ml,无内源性杂质干扰.     

A UFLC/MS/MS method for simultaneous quantitation of alisol A and alisol B 23-acetate from Alisma orientale (Sam.) Juz. in rat plasma

A sensitive and reliable ultra fast liquid chromatography tandem mass spectrometry (UFLC-MS/MS) method has been developed and validated for simultaneous quantitation of alisol A and alisol B 23-acetate from Alisma orientale (Sam.) Juz. in rat plasma using diazepam as an internal standard (IS). The plasma samples were extracted by liquid–liquid extraction with methyl tert-butyl ether and separated on a Venusil MP C18 column (100 mm × 2.1 mm, 3.0 mm) (Venusil, China) using gradient elution with the mobile phase consisting of methanol and 0.1% acetic acid in water at a flow rate of 0.4 ml/min. The two analytes were monitored with positive electrospray ionization by multiple reaction monitoring mode (MRM). The lower limit of quantitation was 5.00 ng/ml for alisol A and 5.00 ng/ml for alisol B 23-acetate. The calibration curves were linear in the range of 5.00–2500 ng/ml for alisol A and 5–2500 ng/ml for alisol B 23-acetate. The mean extraction recoveries were above 63.8% for alisol A and 68.0% for alisol B 23-acetate from biological matrixes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (15%). The validated method was successfully applied to the pharmacokinetic study of alisol A and alisol B 23-acetate in rat plasma after oral administration of alcohol extract of Alismatis Rhizoma.     

High performance liquid chromatography for quantification of gatifloxacin in rat plasma following automated on-line solid phase extraction

An automated system using on-line solid phase extraction and HPLC with fluorimetric detection was developed and validated for quantification of gatifloxacin in rat plasma. The extraction was carried out using C(18) cartridges (BondElut), with a high extraction yield. After washing, gatifloxacin was eluted from the cartridge with mobile phase onto a C(18) HPLC column. The mobile phase consisted of a mixture of phosphoric acid (2.5mM), methanol, acetonitrile and triethylamine (64.8:15:20:0.2, v/v/v/v, apparent pH(app.) 2.8). All samples and standard solutions were chromatographed at 28 degrees C. The method developed was selective and linear for drug concentrations ranging between 20 and 600 ng/ml. Gatifloxacin recovery ranged from 95.6 to 99.7%, and the limit of quantification was 20 ng/ml. The intra and inter-assay accuracy were up to 94.3%. The precision determined not exceed 5.8% of the CV. High extraction yield up to 95% was obtained. Drug stability in plasma was shown in freezer at -20 degrees C up to 1 month, after three freeze-thaw cycles and for 24h in the autosampler after processing. The assay has been successfully applied to measure gatifloxacin plasma concentrations in pharmacokinetic study in rats.     

High performance liquid chromatographic analysis of rabeprazole in human plasma and its pharmacokinetic application

A simple and sensitive HPLC method for the analysis of rabeprazole in plasma is described using UV detection in the presence of lorazepam as the internal standard. Rabeprazole and lorazepam were extracted with ethyl ether and quantitated using a reverse-phase C(18) column. The method was specific as there were no interfering peaks in the human plasma eluting at the retention times of rabeprazole and lorazepam. The method was fully validated in human plasma for the concentration range of 20.0-1000.0 ng/ml. The correlation coefficients were greater than 0.999. Extraction recoveries were 72.3% for the drug and 79.1% for the internal standard. The method was simple, reliable, and accurate for the quantitation of rabeprazole in human plasma. The same plasma samples, which were collected in healthy male volunteers administered a 20 mg tablet of Pariet, were analyzed by HPLC and LC/MS/MS. As a result of that, there was no significant difference between pharmacokinetic parameters. The suitability of HPLC method for pharmacokinetic studies was verified by determining the relevant pharmacokinetic parameters.     

High performance liquid chromatographic determination of a new antifungal compound, ADKZ in rat plasma

A high performance liquid chromatography (HPLC) method was developed and validated for the determination of ADKZ (1-(1H-1,2,4-triazole)-2-(2,4-diflurophenyl) -3-[N-methyl-N-(4-iodo-benzyl)amino]-2-propanol) in rat plasma. The compound was extracted from plasma samples by liquid-liquid extraction, and an isomeric compound of ADKZ (1-(1H-1,2,4-triazole)-2-(2,4-diflurophenyl)-3-[N-methyl-N -(3-iodo-benzyl)amino]-2-propanol) was used as the internal standard (IS), which were analyzed on a reversed-phase C18 column (5 microm, 200 mm x 4.6 mm i.d.). The extracted plasma samples were eluted with acetonitrile-0.018 M triethylamine solution adjusted to pH 3.2 with phosphoric acid (35:65, v/v). The effluent was monitored by a UV detector at 230 nm. The retention time of ADKZ was 7.1 min and IS 8.2 min. The calibration curves were linear in the concentration range of 0.02-2.00 microg/ml with the correlation coefficients greater than 0.999. The quantification limit of ADKZ in rat plasma was 0.02 microg/ml. Intra- and inter-day precision ranged from 2.6 to 7.9% and 3.1 to 9.6%, respectively. The extraction recovery from plasma was no less than 80%. No endogenous interferences were observed with either ADKZ or IS. The method has been successfully used to support the pre-clinical pharmacokinetic studies of ADKZ in rats.     

High performance liquid chromatographic analysis of cimetidine in serum

A rapid and reliable micro procedure for the high pressure liquid chromatographic analysis of cimetidine. N"-cyano-N-methyl-N'-[2-[[(5-methyl-1H-imidazol-4-yl)methyl]thio]ethyl]guanidine, in serum or plasma is described. The percentage analytical recovery of cimetidine and internal standard (beta-hydroxypropyl-theophylline) was 65 and 99%, respectively. The between-day precision of the method at cimetidine serum concentrations of 2,000, 1,000, and 500 microgram/liter yielded coefficients of variation of 10.6, 11.5, and 10.6%, respectively. The method has been used in preliminary studies to determine the serum concentrations in patients receiving the drug by both the oral and intravenous route.     

Validation of a sensitive LC/MS/MS method for simultaneous quantitation of flupentixol and melitracene in human plasma

A sensitive method has been developed and validated, using LC/ESI-MS/MS, for simultaneous quantitation of flupentixol and melitracen—antidepressant drugs, in human plasma. The quantitation of the target compounds was determined in a positive ion mode and multiple reaction monitoring (MRM). The method involved a repeated liquid–liquid extraction with diethyl ether and analytes were chromatographed on a C₈ chromatographic column by elution with acetonitrile–water–formic acid (36:64:1, v/v/v) and analyzed by tandem mass spectrometry. The method was validated over the concentration ranges of 26.1–2090 pg/ml for flupentixol and 0.206–4120 ng/ml for melitracen. The correlation coefficients of both analyst were >0.998 for six sets of calibration curves. The recovery was 60.9–75.1% for flupentixol, melitracen and internal standard. The lower limit of quantitation (LLOQ) detection was 26.1 pg/ml for flupentixol and 0.206 ng/ml for melitracen. Intra- and inter-day precision of the assay at three concentrations were 2.15–5.92% with accuracy of 97.6–103.0% for flupentixol and 0.5–6.36% with accuracy of 98.7–101.7% for melitracen. Stability of compounds was established in a battery of stability studies, i.e., bench-top, autosampler and long-term storage stability as well as freeze/thaw cycles. The method proved to be suitable for bioequivalence study of flupentixol and melitracen in healthy human male volunteers.     

Sensitive high performance liquid chromatographic analysis of ethmozin in plasma

A sensitive high performance liquid chromatographic procedure for the quantitative determination of ethmozin is described. Following a one-step extraction of the drug and the internal standard, protriptyline, by diethylether at pH 9.0, the organic solvent is evaporated and the residue is reconstituted in the mobile phase and injected into the chromatograph. The separation is obtained using a CN-bonded column with a methanol-propanol-2-perchloric acid 1.16 M mobile phase. Ethmozin is detected at 268 nm. Under these conditions, the lower limit of detection is 11 nM, and the lower limit of quantification is 22 nM (10 ng/ml) for ethmozin. The procedure is linear between 0 and 8,620 nM.     

Development and validation of a LC-MS/MS method with electrospray ionization for determination of LASSBio-579 in rat plasma

A simple and sensitive LC-MS/MS analytical method was developed and validated for the determination of LASSBio-579 in plasma rat, using fluconazole as internal standard. Analyses were performed on a Shimadzu HPLC system using a Shimadzu C18 column and isocratic elution with acetonitrile-water (80:20, v/v), containing 0.4mM ammonium hydroxide and 0.2 mM acetic acid at a flow rate of 1.0 ml/min (split ratio 1:5). A Micromass triple quadrupole mass spectrometer, equipped with an electrospray ionization interface, operated in the positive mode. Plasma samples were deproteinized with acetonitrile (1:2) and 50 microl of the supernatant were injected into the system. The retention times of LASSBio-579 and IS were approximately 4.7 and 2.4 min, respectively. Calibration curves in spiked plasma were linear over the concentration range of 30-2000 ng/ml with determination coefficient >0.98. The lower limit of quantification was 30 ng/ml. The accuracy of method was within 15%. Intra- and inter-day relative standard deviations were less or equal to 13.5% and 6.4%, respectively. The applicability of the LC-MS/MS method for pharmacokinetic studies was tested using plasma samples obtained after intraperitoneal administration of LASSBio-579 to male Wistar rats. No interference from endogenous substances was observed, showing the specificity of the method developed. The reported method can provide the necessary sensitivity, linearity, precision, accuracy, and specificity to allow the determination of LASSBio-579 in pre-clinical pharmacokinetic studies.     

High performance liquid chromatographic determination of a new biologically active 1,2,4-oxadiazine derivative in rat plasma

A sensitive high performance liquid chromatographic procedure was developed for the determination of 3-phenyl-6-(1,2,3,4-tetrahydro-2-isoquinolyl)methyl-4H-5,6-dihydro -1,2, 4-oxadiazine a new vasodilator, in plasma. Rat plasma samples were made alkaline with ammonia and partitioned with chloroform. The extracts were dried with anhydrous sodium sulphate and evaporated to dryness under reduced pressure. The residues were redissolved in chloroform, and then chromatographed on silica column with chloroform/isopropanol (7:3, v/v). Detection was performed with a variable-wavelength UV detector set at 265 nm. Limit of identification was 10 ng, that of quantitative determination 50 ng 1/ml of plasma. The utility of the method for pharmacokinetic studies in the rat was demonstrated.     

高效液相色谱法测定人血浆中硝苯地平的浓度

目的:建立高效液相色谱法测定人血浆中硝苯地平的浓度.方法:分析柱为Micro Pah C 18分析柱.流动相为甲醇:水:冰乙酸:正丁胺(77:23:0.02:O.01).检测波长为235nm.采取乙醚二次萃取法提取血浆中的硝苯地平及内标安定.结果:测定硝苯地平的日内及日间精密度的RSD均小于10%.血药浓度在6.16～197.20 ng/ml范围内线性关系良好(r=0.9994).最低检测限为2ng/ml.结论:本方法适用于硝苯地平的药物动力学研究.     

High performance liquid chromatographic analysis of isoflavones in medicinal herbs

Phytoestrogens have been used as a food supplement to prevent osteoporosis. The isoflavones in the phytoestrogens are daidzein, genistein and formononetin which are present in various herbs. This study examined the quantity of isoflavones in medicinal herbs, which can be used as a phytoestrogen supplement; soybean. These isoflavones were quantified using high performance liquid chromatography (HPLC) with a UV/VIS detector. The concentration of daidzein in Puerariae Radix was 10,436.16 +/- 2,143.83 mg/kg of the dried herb, which was much higher than that extracted from soybeans, 341.47 +/- 18.96 mg/kg. The amount of genistein in Sophorae flavescentis Radix (336.09 +/- 50.89 mg/kg) was approximately 11 times higher than that extracted from soybean (30.03 +/- 7.17 mg/kg). The level of formononetin in Dalbergiae odoriferae Lignum, 2,189.14 +/- 136.46 mg/kg, was the highest among the herbs tested. The total isoflavone content of Puerariae Radix was approximately 30 times higher than that extracted from soybean. Therefore, plants from the family Leguminosae, particularly Puerariae Radix, can be a good source of phytoestrogens.     

Improved high performance liquid chromatographic analysis of omeprazole in human plasma

A simple high-performance liquid chromatographic method was developed for the determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of variation and percent error values of the assay method were all less than 14%.     

High performance liquid chromatographic analysis of hydrochlorothiazide in serum and urine

We report a high performance liquid chromatographic method for the analysis of hydrochlorothiazide in 500microliter of serum of 25 microliter of urine. The between-day precision of the analysis (CV 5.0-7.0%) is acceptable, as is the recovery of hydrochlorothiazide (90-96%) and trichloromethiazide (96%) added to serum. No drug or drug metabolite interferences have been noted. The method represents a considerable improvement over existing techniques described in the literature.     

Validation of a GC/MS method for the determination of tramadol in human plasma after intravenous bolus

Tramadol quantitative determination by gas chromatography-mass spectrometry (GC/MS) using nefopam hydrochloride as internal standard (IS) and two calibration curves because of the large range of concentration attended in the plasmatic samples is described. Plasma samples drawn from subjects in postoperative period treated with two different initial intravenous (iv) bolus of tramadol (50 and 100 mg) followed by tramadol at the same infusion rate (12 mg h(-1)) are analysed. We operated for the qualitative analysis in Scan mode while for the quantitative analysis in SIM mode, selecting the ion m/z 58 for tramadol and m/z 179 for IS. The limit of detection (LOD) was 0.01 microg ml(-1) and the limit of quantification was 0.04 microg ml(-1).     

High performance liquid chromatographic assay for the quantitation of total glutathione in plasma

A simple and widely used homocysteine HPLC procedure was applied for the HPLC identification and quantitation of glutathione in plasma. The method, which utilizes SBDF as a derivatizing agent utilizes only 50 microl of sample volume. Linear quantitative response curve was generated for glutathione over a concentration range of 0.3125-62.50 micromol/l. Linear regression analysis of the standard curve exhibited correlation coefficient of 0.999. Limit of detection (LOD) and limit of quantitation (LOQ) values were 5.0 and 15 pmol, respectively. Glutathione recovery using this method was nearly complete (above 96%). Intra-assay and inter-assay precision studies reflected a high level of reliability and reproducibility of the method. The applicability of the method for the quantitation of glutathione was demonstrated successfully using human and rat plasma samples.