Simple high-performance liquid chromatographic determination of buspirone in human plasma

A simple, rapid and sensitive high-performance liquid chromatographic method for the determination of buspirone in plasma was developed. Buspirone was isolated from plasma using protein precipitation by acetonitrile and the recovery was complete. Citalopram was used as internal standard. The chromatographic conditions were as follows: analytical 125 x 4 mm, i.d. Nucleosil C18 column (5 microm particle size), mobile phase consisting of sodium dihydrogen phosphate buffer/acetonitrile (60:40, v/v) adjusted to pH 5.5 at a flow rate of 1.0 ml min(-1), UV detection at 235 nm. The quantification limit for buspirone in plasma was 0.5 ng ml(-1).The calibration curve was linear over the concentration range 0.5-10 ng ml(-1). The inter- and intra-day assay coefficients of variation were found to be less than 8%. The present validated method was successfully used for bioequivalence studies of buspirone in human subjects.     

高效液相色谱法测定人血清中伊曲康唑浓度

目的：建立了ＨＰＬＣ法测定血清样品中伊曲康唑的定量分析方法。方法：色谱条件：以ＺＯＲＢＡＸＴＭＣ１８（５μｍ,４．６×１５０ｍｍ）为色谱柱;乙腈水（６７．５∶３２．５）为流动相,检测波长２６３ｎｍ;用正庚烷∶异戊醇（９８．５∶１．５）作为提取剂。结果：三种浓度４０,８０,３００ｎｇ·ｍｌ－１回收率分别为１０５．０５％,１００．５７％,９７．９１％（ｎ＝６）;日内、日间ＲＳＤ分别为３．８３％,４．０５％,３．０９％及６．００％,４．９０％,４．７２％（ｎ＝６）。血清中药物的最低检测浓度为５ｎｇ·ｍｌ－１,在５～６００ｎｇ·ｍｌ－１血药浓度范围内线性关系良好,ｒ＝０．９９９５。结论：方法灵敏、准确、结果满意     

Separation and determination of synthetic impurities of norfloxacin by reversed-phase high performance liquid chromatography

A simple and rapid high performance liquid chromatographic method for the separation and determination of synthetic impurities of norfloxacin was developed. The separation was achieved on a reversed-phase C₁₈ column using 0.01 M potassium dihydrogen orthophosphate and acetonitrile (60:40, v/v, pH 3.0) as mobile solvent at a flow rate of 1.0 ml/min at 40 °C and a UV detection at 260 nm. The method was used not only for quality assurance but also for monitoring the chemical reactions during the process development work in the laboratory. It was found to be specific, precise and reliable for determination of unreacted levels of raw materials, intermediates and the finished products of norfloxacin.     

HPLC法测定人血清及尿中美洛培南浓度

目的　建立测定人血清样品及尿样品中美洛培南的定量分析方法。方法　采用高效液相色谱法 ,以 μ- Bondapak C1 8柱 (3.9mm× 30 0 mm,10 μm)为色谱柱 ;甲醇∶ 5 mmol/ L 磷酸二氢钾缓冲液 (17∶ 83,v/ v)为流动相 ,p H2 .5 ,检测波长 30 8nm。结果　血清中美洛培南的回收率平均为 97.5 4 % (n=6 ) ;日内 ,日间RSD≤ 3.80 % ,在 1～ 10 0 mg/ L 血药浓度范围内线性关系良好 ,r=0 .9997。尿中美洛培南的平均回收率为96 .90 % (n=6 ) ;日内、日间 RSD<3.5 0 % ,在 5～ 10 0 mg/ L 尿药浓度范围内线性关系良好 ,r=0 .9994。结论该方法灵敏准确 ,适用于临床药代动力学的研究。     

High-performance liquid chromatographic method for the bioequivalence evaluation of desloratadine fumarate tablets in dogs

A simple HPLC method was developed for the determination of desloratadine in dog plasma and was used for evaluating the bioequivalence of desloratadine fumarate tablets and desloratadine tablets in dogs. Chromatographic separation was performed on a Hypersil CN column (150 mm×5.0 mm, 5 μm) using a mixture of methanol, acetonitrile and phosphate buffer (pH 5.5; 0.01 mol/l) (35:35:30, v/v/v) as mobile phase delivered at a flow rate of 0.8 ml/min. The detection was set at 241 nm. The limit of quantitation was 5.0 ng/ml. The calibration range was from 5.0 to 800.0 ng/ml. Inter- and intra-day precision ranged from 1.8 to 3.8% and from 2.2 to 9.0%, respectively. The recovery of desloratadine from dog plasma ranged from 78.8 to 82.0%. The developed method was applied to the bioequivalence studies of desloratadine fumarate tablets (test preparation) and desloratadine tablets (reference preparation) in five dogs. Pharmacokinetic parameters t_max, C_max, AUC_0–t, AUC_0–∞, t_1/2 were determined from plasma concentration-time profiles of both preparations. The analysis of variance (ANOVA) did not show any significant difference between the two preparations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two preparations exhibited comparable pharmacokinetic profiles and that desloratadine fumarate tablets was bioequivalent to desloratadine tablets.     

高效液相色谱法测定人血浆中伏立康唑浓度

目的：建立一种简单高效的高效液相色谱（HPLC）法用来检测人体中伏立康唑的血药浓度，并应用于临床中伏立康唑用药监测，以促进其个体化用药。方法：色谱柱：Kromasil C₁₈（4.6 mm×150 mm，5 μm），柱温：35℃，流速：1.0 mL·min^-1，流动相：甲醇-水（60：40），检测波长：257 nm，内标：酮康唑。对该方法进行方法学验证。结果：该方法专属性良好，血浆中伏立康唑在0.1~20.0 μg·mL^-1范围内线性良好（r=0.999 6），定量下限为0.1 μg·mL^-1。高、中、低3个浓度提取回收率分别为（90.68±10.32）%、（92.82±8.26）%、（97.47±4.58）%；日内精密度RSD分别为5.87%、7.85%、4.10%；日间精密度RSD分别为5.64%、3.30%、2.74%。对某院20例（男12例，女8例）使用伏立康唑抗真菌治疗的患者运用该方法进行了监测，结果显示浓度范围在0.71~13.51 μg·mL^-1之间。结论：本方法专属性高，操作简便，结果准确，可用于临床上伏立康唑血药浓度的检测，从而促进其个体化用药的推广。     

高效液相色谱法测定血浆中伊立替康的含量

目的建立血浆中伊立替康含量的测定方法。方法以C18色谱柱、0．05mol／LNa2HPO4(pH=3．0,内含0．05mol／L辛烷基磺酸钠)-乙腈=68：32为流动相分离、荧光检测伊立替康,外标法定量。结果伊立替康浓度在25．0-1000μg／L内,浓度与峰面积之间有良好的线性关系(C=0．00249A-8．15,r=0．9994)。最小检出质量浓度为2．0μg／L。50,100,500μg／L伊立替康的相对回收率(％)分别为96．4、98．3和100．4。三个浓度的平均日内RSD为2．87％,平均日间RSD为4．30％。结论本方法快速、简便、准确,可用于科研和临床工作中伊立替康血药浓度的快速检测。     

高效液相色谱法测定人体中羟苯磺酸钙的浓度

高效液相色谱法测定人体中羟苯磺酸钙的浓度@郭栋$Institute of Clinical Pharmacology, Central South University!Changsha 410078, Hunan, China @谭志荣$Institute of Clinical Pharmacology, Central South University!Changsha 410078, Hunan, China @欧阳冬生$Institute of Clinical Pharmacology, Central South University!Changsha 410078, Hunan, China @周宏灏$Institute of Clinical Pharmacology, Central South University!Changsha 410078, Hunan, China…     

用反相高效液相色谱法测定血浆中萘丁美酮活性代谢物

萘丁美酮为国内新仿制成的一种新型非甾体抗炎药物,具有抗炎作用强,作用时间持久,毒副作用小等特点,萘丁美酮系一前体药物,在体内有多种代谢产物,其主要活性代谢物为6—甲氧基—2—萘乙酸(6—MNA)。本文用反相高效液相色谱法,以2—(6—甲氧基—2—)萘丙酸(6—MNP)为内标,测定了人体血浆中萘丁美酮活性代谢物6—MNA的血药浓度,测试结果表明:6—MNA的浓度在1--40μg/ml范围内,样品峰和内标峰的面积比值与浓度具有良好的线性关系,标准曲线的相关系数为0.9997。3种不同浓度(5、10、20μg/ml)的日内变异系数分别为4.82%,3.49%,2.44%,样品提取回收率为84.57～88.23%。方法回收率为94.03～100.15%。实验结果表明:用反相高效液相色谱法测定人血浆中6—MNA的含量,具有方法简单,结果可靠,实用性好等优点。     

高效液相色谱法测定美林洛尔与人血浆蛋白的结合率

目的建立人标准血浆中美林洛尔(MELE)浓度的测定方法,测定美林洛尔在人标准血浆中的蛋白结合率,并计算相关参数.方法用平衡透析法测定血浆蛋白结合率,用高效液相-荧光检测法测定血浆中药物总浓度及游离药物浓度.结果美林洛尔与人标准血浆的蛋白结合率随药物浓度发生变化约为7.02%～18.75%.MELE与白蛋白结合的表现最大能力βp为0.016μmol·g-1,药物-蛋白复合物的解离常数Kdp为1.734 μmol·L-1,结合常数Kp为1.271 9×103L·mol-1,结合位点n为0.001 6.结论在体外美林洛尔与人标准血浆的蛋白结合率较低,并随着药物浓度的增加结合率下降.     

Spectrophotometric determination of labetalol in pharmaceutical preparations and spiked human urine

Two simple and sensitive spectrophotometric methods were developed for the spectrophotometric determination of labetaolol (LBT). Both methods are based on the phenolic nature of the drug. The first method (Method I) is based on coupling LBT with diazotized benzocaine in presence of trimethylamine. A yellow colour peaking at 410 nm was produced and its absorbance is linear with the concentration over the range 1-10 microg ml(-1) with correlation coefficient (n=5) of 0.9993. The molar absorptivity was 2.633 x 10(4) l mol(-1) cm(-1). The second method (Method II) involves coupling LBT with diazotized p-nitroaniline in presence of sodium carbonate. An orange colour peaking at 456 nm was obtained and its absorbance is linear with concentration over the range 1-10 microg ml(-1) with correlation coefficient (n=5) of 0.99935. The stoichiometry of the reaction in both cases was accomplished adopting the limiting logarithmic method and was found to be 1:1. The developed method could be successfully applied to commercial tablets. The results obtained were in good agreement with those obtained using the official methods. No interference was encountered from co-formulated drugs, such as hydrochlorothiazide. The method was further extended to the in-vitro determination of LBT in spiked human urine. The % recovery (n=4) were 97.7+/-5.75 and 103.27+/-5.42 using the Methods I and II, respectively.     

High performance liquid chromatographic determination of moxalactam in human plasma and cerebrospinal fluid

Summary A sensitive and reproducible method for the measurement of moxalactam in plasma and cerebrospinal fluid is described. Plasma proteins were removed by precipitation with ice-cold methanol at pH 5.6 and centrifugation. The supernatant was analysed by HPLC on a µ-Bondapack/phenyl column, with a mobile phase of acetonitrile/water/PIC Reagent A (20/80/1), and detection at 280 nm. The calibration curve was linear for plasma concentrations from 10 µg/ml to 60 µg/ml. Reproducibility was 4.7% (coefficient of variation) for within-day analysis and 13.8% for day-to-day analysis. Plasma concentrations in 9 moxalactam-treated patients with severe infections ranged from 0.9 µg/ml to 409 µg/ml. Individual pharmacokinetic parameters were calculated using a personal computer. In selected cases moxalactam concentrations were also determined in cerebrospinal fluid and tracheal aspirates.     

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.     

Fast liquid chromatographic-tandem mass spectrometric (LC-MS-MS) determination of metformin in plasma samples

Liquid chromatographic–tandem mass spectrometric (LC–MS–MS) methods for the determination of metformin in plasma from different species are presented. The first method employed a YMC cyano 2 mm×50 mm, 3 μm analytical column. For minimum sample preparation direct injection of samples after protein precipitation was performed. The polar column used with highly organic mobile phases provided a normal phase retention mechanism. The elution conditions were optimized to obtain reproducible peak areas and good peak shape. A step gradient from 100% acetonitrile to acetonitrile–water 80:20 (v/v) containing 10 mM ammonium acetate and 1% acetic acid was applied, leading to a sample-to-sample cycle time of 2 min. In a second method, a column-switching LC–MS–MS assay for on-line trapping was developed. The analyte and internal standard were trapped on a YMC cyano 2 mm×10 mm, 5 μm column using acetonitrile–methanol 95:5 (v/v). Elution was performed isocratically in back-flush mode on to the analytical column (YMC cyano 2 mm×50 mm, 3 μm) using 10 mM ammonium acetate in acetonitrile–water 80:20 (v/v) with 1% formic acid. With this approach, the signal-to-noise ratio was improved and the run time could be shortened to 1 min. Calibration samples were prepared in the matrix to be assayed in the range of 10–10,000 ng/ml. Quality control (QC) samples were prepared at 40, 400 and 4000 ng/ml and interspersed with the unknown study samples in the assays. Deviations for precision and accuracy were less than 20% for the lower limit of quantification (LLOQ) and low QC sample and less than 15% for other calibrators and QCs.     

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.     

高效液相色谱法测定布洛芬与人血浆蛋白的结合率

目的:建立人血浆中布洛芬浓度的测定方法,测定布洛芬在人血浆中的蛋白结合率,并计算相关参数。方法:用平衡透析法以高效液相色谱法为检测手段测定血浆蛋白结合率。结果:布洛芬与人标准血浆的蛋白结合率为(95.4±0.3)%。结论:布洛芬与人血浆蛋白为高强度结合。     

High performance liquid chromatographic assay for the simultaneous determination of midazolam and ketoconazole in plasma

A high performance liquid chromatographic (HPLC) assay was developed for the simultaneous quantitation of midazolam (MDZ) and ketoconazole (KTZ) in plasma. MDZ, KTZ and diazepam (internal standard) were extracted from 100 μL or 500 μL plasma from rat or human, respectively, using liquid–liquid extraction with diethyl ether in the presence of 0.1N NaOH. After vortexing, centrifugation and freezing, the organic layer was transferred to clean tubes and evaporated. The dried residue was reconstituted in mobile phase and injected into the HPLC through a C18 column. The mobile phase consisted of acetonitrile:15 mM potassium dihydrogen orthophosphate (45:55, v/v), pumped at 1 mL/min and measured at λ = 220 nm. The method was tested in a pharmacokinetic study involving orally dosed KTZ 40 mg/kg in 1% methylcellulose followed by intravenous dosing of 5 mg/kg MDZ to rats 1.5 h latter. The components eluted within 10 min and were baseline resolved with no interferences from endogenous substances in plasma. The calibration curves were linear (r² = 0.999) over the range of 25–25,000 and 5–10,000 ng/mL of KTZ and MDZ in rat and human plasma, respectively. The intraday and interday CV% were <15% and <6% for KTZ and <7% and <4% for MDZ and the mean error was <13% for both drugs in rat plasma. In human plasma the intraday CV% and % error of the mean were <11% and <10% for KTZ, respectively; both values were <13% for MDZ. The validated lower limit of quantitation was 25 and 5 ng/mL for both drugs based on 100 μL rat plasma and 500 μL human plasma, respectively. In rats, plasma concentrations of MDZ and KTZ were simultaneously measured up to 8 and 9.5 h, respectively. In conclusion, the assay was shown to be rapid, sensitive and appropriate for use in drug–drug interaction studies involving MDZ and KTZ in rat, and potentially in humans.     

高效液相色谱法测定人体血浆中甲氨蝶呤浓度方法的改进

目的:建立高效液相色谱法测定人体血浆中甲氨蝶呤浓度的方法。方法:血浆样品经处理后,色谱分离采用Zorbax-ODSC18(250mm×4.6mm,5μm)色谱柱,检测波长为302nm,流动相为0.01mol.L-1磷酸盐(用磷酸溶液调pH6.7)-甲醇(80∶20),流速为1.0mL.min-1,柱温为35℃。结果:甲氨蝶呤血药质量浓度在0.2～50mg.L-1(r=0.9997)范围内线性关系良好,最低检测质量浓度为5μg.L-1,提取回收率为96.5%～98.7%,方法回收率为98.2%～101.2%,日内、日间RSD分别为3.62%和4.57%。结论:该方法简单、快速、准确适用于临床甲氨蝶呤浓度监测及药动学研究。     

Electrochemical behavior and determination of amiloride drug in bulk form and pharmaceutical formulation at mercury electrodes

The polarographic behavior of amiloride hydrochloride has been studied in Britton–Robinson buffers of pH 1.9–11. In acidic medium at pH≤2, the dc-polarograms exhibited a single 4-electron cathodic irreversible wave, while at pH values >2, a second two-electron irreversible cathodic wave appeared at a more negative potential. The single or first wave may be attributed to the cleavage of the double bond of the ---CH=NH of the imidino amide group with the release of NH₃. While the second wave may be due to the saturation of the C=O of the carboxamide moiety. A polarographic procedure of suffocate sensitivity for the determination of bulk amiloride drug in Britton–Robinson buffer at pH 2 is described. The calibration graph was obtained over the concentration range 2.5×10⁻⁵ to 2.5×10⁻⁴ M amiloride. The limits of detection (LOD) and quantitation (LOQ) of the procedure were 1×10⁻⁵ and 3.3×10⁻⁴ M bulk amiloride, respectively. Moreover, a differential-pulse adsorptive cathodic stripping voltammetric procedure has been described to assay of the drug at lower concentration levels. The optimal conditions were: E_acc=−0.9 V, t_acc=30 s, scan rate=20 mV, pulse-height=90 mV and Britton–Robinson buffer of pH 8. The calibration graph was obtained over the concentration range 2×10⁻⁸ to 1×10⁻⁶ M for bulk amiloride. Both procedures were successfully applied to the determination of amiloride in tablets without the necessity for sample pretreatment or any time-consuming extraction or evaporation steps prior to the drug analysis.     

Application of the HPLC method for benzalkonium chloride determination in aerosol preparations

Benzalkonium chloride (BAC) is a bacteriostatic agent used in the pharmaceutical industry as a preservative. BAC is a mixture of alkylbenzyldimethylammonium chlorides, the three most important of which being those with alkyl substituents C12, C14, C16 at the quaternary ammonium salt.

The purpose of this study was to develop a method for determining benzalkonium chloride identity and content in aerosol preparations in which protein or steroid hormones are the active components. The high performance liquid chromatography (HPLC) method was used for this purpose. In the performed comparison of the influence of selected factors on the process of the separation of BAC homologues, a column with packing modified with cyan groups and mobile phase containing 0.075 M acetate buffer with acetonitrile (45:55), in an isocratic elution, was used for qualitative and quantitative determinations and for method validation. The developed method may be used for the assessment of the identity and content of BAC homologues in various pharmaceutical preparations. It is simple and it does not require particular sample preparation for the tests. It is characterized by good selectivity and high precision of the determinations.