Improvement of the quantitative determination of verapamil in human plasma.

An improvement in the extraction procedure for the quantitative determination of verapamil in human plasma is described. The advantages are: 1. the time involved in the extraction procedure is only 1/3 of that in the original method allowing the extraction of 100 samples in a working day. 2. increased mean recovery from 67% to 85% over the range of 3--90 ng verapamil/ml plasma. 3. less expenditure a) use of cheap plastic tubes instead of stoppered glass tubes. b) 1/2 the amount of heptane required as compared to the original procedure. c) use of air instead of N2 for evaporation. The lower limit of detection is 3 ng/ml which is comparable to that for the original extraction procedure. Within-batch precision over the range of 9--90 ng/ml averages 5.8% and at the lower limit of detection 17.3%. Between-batch precision over the range of 9--90 ng/ml averages 8.5% and at the lower limit of detection 19.7%. No significant difference could be found in the quantitative determination of verapamil in 27 plasma samples from patients undergoing verapamil treatment using the original and modified extraction procedures. This improvement of the extraction procedures simplifies the determination of verapamil and the only additional material required is liquid nitrogen or a suitable solvent cooled with dry ice.     

高效液相色谱法测定人血浆中阿糖胞苷的浓度

目的:建立以高效液相色谱法测定人血浆中阿糖胞苷浓度的方法。方法:色谱柱为Zorbax C18,检测波长为280nm,流动相为0·01mol/L磷酸盐(pH=7·0)-乙腈(95∶5),流速为1·0ml/min。结果:阿糖胞苷血药浓度在0·05~20μg/ml(r=0·9999)范围内线性关系良好,最低检测浓度为2ng/ml,方法回收率为98·3%~103·2%,日内、日间相对标准差分别为2·8%、3·6%。结论:本方法简单、快速、准确,适用于阿糖胞苷临床血药浓度监测和药动学研究。     

HPLC determination of 5-hydroxypropafenone in plasma with electrochemical detection

A high pressure liquid chromatographic (HPLC) method with internal analogue standardization for the determination of 5-hydroxypropafenone in plasma is described. The method comprises extraction from plasma at pH 9 with diethyl-ether and quantification after HPLC separation using a reverse phase by means of electrochemical (reductive) detection after electrochemical preoxidation. When using 1 ml plasma the lower limit of detection is 0.5 ng/ml. Under routine conditions the limit of determination is estimated to be lower than 2 ng/ml. The variation coefficients of duplicates drop from about 10% in the range of the determination limit to about 3% at 5 ng/ml and above. The determination of 5-hydroxypropafenone is not impaired by other known metabolites of propafenone.     

反相高效液相色谱-荧光法测定血浆中丙泊酚的浓度

目的 :建立反相高效液相色谱 -荧光检测法测定血浆中丙泊酚浓度的方法。方法 :采用ZorbaxEclipseXDB -C18 色谱柱(150mm×4 6mm ,5μm) ,甲醇 -乙腈 -0 005mol/L醋酸钠缓冲液 (pH4 0)=55∶20∶25(V/V)为流动相 ,样品提取分离后用流动相溶解 ,在Ex/Em=276/310nm波长处检测。结果:本法测定的标准曲线在0 015625～8μg/ml浓度范围内线性关系良好(r=0 9998) ,灵敏度为1ng/ml(S/N=3) ,最低检测浓度为10ng/ml,绝对回收率在89 33 %～93 37 %之间 ,方法回收率在97 75 %～103 31 %之间 ,日内、日间变异系数分别为1 38 %～5 02 %、4 45 %～9 056 %。结论 :用本方法检测丙泊酚的血药浓度方便、稳定、灵敏度高 ,可满足临床药动学研究要求     

HPLC测定血浆中吡咯地尔浓度

建立了测定吡咯地尔血浆药物浓度的HPLC.采用YWG-C_(18)柱(10μm,15cm×4.6mm I.D.),检测波UV254nm,流动相为甲醇:水:10%三乙胺磷酸缓冲液(pH4.5):二氯甲烷=75:15:10:5,流速1.0ml/min;1.0ml血浆用正己烷:异丁醇(98:2)提取,内标法定量.线性范围10～2000ng/ml,最低检测浓度3ng/ml.平均提取回收率90.02%,平均方法回收率100.33%,日内RSD<4.0%,日间RSD<5.5%.     

A rapid reversed phase high performance liquid chromatographic method for determination of etoposide (VP-16) in human plasma

A rapid, simple and sensitive isocratic High Performance Liquid Chromatography (HPLC) method was developed to measure the concentration of etoposide in plasma samples with UV detection at 220 nm. The method uses a Bondapac C18 column at 60 degrees C. The mobile phase consists of Methanol: water (45:55 v/v) at a flow rate of 2.8 ml/min. Phenacetin was used as an internal standard. The plasma samples were extracted using ether with the organic layer evaporated under nitrogen. The residue was dissolved in 200 microl methanol with 20 microl injected into the HPLC column. The extraction method showed a recovery of 91.5+/-3% for etoposide. In this system, the retention time of phenacetin and etoposide were 3.3 and 4.4 min, respectively. The limit of detection of etoposide in plasma is 20 ng/ml and the limit of quantitation is 40 ng/ml. This analytical method has very good reproducibility (8.1% between-day variability at a concentration of 50 ng/ml). It is a fast, sensitive and economic method applicable for clinical and pharmacokinetic studies.     

高效液相色谱法测定人血浆中西洛他唑浓度

目的:建立以高效液相色谱法测定人血浆中西洛他唑浓度的方法。方法:色谱柱为C18,流动相为甲醇-0.03mol/L醋酸铵(62∶38,V/V),流速为0.8ml/min,检测波长为257nm,以乙酸乙酯为提取剂。结果:西洛他唑检测浓度在10.0~1500.0ng/ml范围内线性关系良好(r=0.9999),高、中、低系列浓度的平均回收率分别为99.82%、97.30%、97.14%,日内和日间RSD均小于6%。结论:本方法灵敏、准确、简单、快速,可用于临床血药浓度监测和药动学研究。     

Simultaneous determination of propafenone and 5-hydroxypropafenone in plasma by means of high pressure liquid chromatography

A high pressure liquid chromatographic (HPLC) method with internal analogue standardization for the simultaneous determination of propafenone and 5-hydroxypropafenone in plasma is described. The method comprises extraction from plasma at pH 9 with toluene/dichloromethane/isopropanol, derivatization with dansylhydrazine and subsequent elimination of fluorescent byproducts via silica gel disposable columns followed by quantification by means of fluorescence detection after HPLC separation using a normal phase. With a sample volume of 1 ml the lower limit of detection for propafenone and 5-hydroxypropafenone is approximately 0.2 ng/ml, the limit of determination (precision limit 10%) is approximately 1 ng/ml. The variation coefficients decrease from approximately 10% in the low range to 6-9% for propafenone and 3-7% for 5-hydroxypropafenone at 2 ng/ml and above. For both substances a mean weighted relative error of 6% has to be expected.     

The determination of minoxidil in human serum by high-performance liquid chromatography with amperometric detection

An ion-pairing reversed-phase HPLC assay employing amperometric detection has been developed for the determination of free minoxidil (MNX) in human serum. The drug is isolated from the serum and concentrated by solid phase extraction with a disposable cartridge column containing ethylsilane (C2) bonded phase packing material. The average absolute recovery from serum was 85%. The HPLC separation is performed on a Sperisorb-C(8) column, using n-octanesulphonic acid as the pairing ion. The method exhibits linear behaviour from 0.3 to 100 ng/ml for spiked serum samples. The average daily relative standard deviations of replicate samples at the 0.75 and 2.0 ng/ml levels were 9.6 and 6.4%, respectively. Utilizing a 1 ml sample the limit of detection (S/N 3) was 0.3 ng/ml.     

SPE-HPLC-FLU法检测人血浆样品中维拉帕米

目的建立一种简单、快捷、灵敏、准确的监测人血浆样品中维拉帕米的方法。方法采用SPE方法处理血浆样品;加洛帕米为内标,醋酸-醋酸钠溶液:甲醇:三乙胺(45:55:1)为流动相,应用HPLC色谱法配合荧光检测,荧光检测波长275nm。结果所得色谱图中维拉帕米与内标能很好分离,无明显杂质峰的影响。建立的方法经验证,线性范围为5～500ng.mL-1,检测限为1.4ng.mL-1,定量限为5.0ng.mL-1,平均加样回收率分别是90.7%、88.2%和90.2%,精密度试验RSD值<15%,各种稳定性试验中RSD值均<20%。结论该方法简单、快捷、灵敏、准确,适用于临床维拉帕米的血药浓度监测。     

High-Performance Liquid Chromatographic (HPLC) Assay Using Fluorescence Detection for the Simultaneous Determination of Gallopamil and Norgallopamil in Human Plasma

Gallopamil is a calcium-channel antagonist with reported activity in experimental animals three to five times higher than that of verapamil. An automated high-performance liquid chromatographic (HPLC) method with fluorescence detection is described for the simultaneous determination of gallopamil and its metabolite norgallopamil in plasma. Gallopamil was well resolved from norgallopamil and other metabolites, allowing simultaneous quantitation of both drugs. The detection limit for both gallopamil and norgallopamil was 0.9 ng/ml. This method has been successfully used for the determination of gallopamil and norgallopamil following the administration of 25-, 37.5-, and 50-mg oral doses of drug.     

高效液相色谱法测定人血浆中头孢克肟浓度

目的 :建立以高效液相色谱法测定头孢克肟血药浓度的方法。方法 :以DiscoveryC18(250mm×4 6mm ,5μm )为分析柱 ,甲醇 -醋酸盐缓冲液 -三乙胺 (28∶72∶0 5)为流动相 ,检测波长为286nm ,流速为1 0ml/min ,头孢拉定为内标物 ,测定头孢克肟血药浓度。结果 :头孢克肟在0 1～5 0μg/ml检测浓度范围内呈良好线性关系 (r=0 9995) ;高、中、低3种浓度的日间RSD≤6 69 %、日内RSD≤6 10 % ;相对回收率为 (96 63±3 17) %。结论 :该方法操作简便、灵敏、准确 ,适用于临床头孢克肟的血药浓度测定及药动学研究     

HPLC-紫外法测定人血浆中芬太尼浓度

目的 :建立高效液相色谱法 -紫外检测器测定人血浆中芬太尼浓度的方法。方法 :本实验采用外标法 ,以Shim -PackCLC -ODS(6 0mm×150mm ,5μm )为固定相 ,含0 015mol/LNaH2PO4 的乙腈 -水溶液 (30∶70 ,v/v)为流动相 ,流速1 5ml/min ,紫外检测波长195nm。结果 :标准曲线在2 0～100ng/ml范围内线性关系良好 (r=0 999) ,最低检测浓度为1ng/ml,方法回收率为(91 70±4 70) % ,提取回收率为 (97 38±3 69) % ,日内变异RSD (6 50±2 79) % ,日间变异RSD (6 70±3 04) %。结论 :本方法简便 ,准确 ,检测浓度低 ,能够满足血浆中低浓度芬太尼的测定及临床药代动力学研究的要求。     

Determination of trimethoquinol in plasma by electrochemical detection after HPLC separation

A high pressure liquid chromatographic method with internal analogue standardization for the determination of trimethoquinol (1-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoq uinoline hydrochloride) in plasma is described. The method comprises extraction from plasma at pH 9 with ethyl acetate, back-extraction into phosphoric acid and quantification after HPLC separation using a reverse phase by means of electrochemical (reductive) detection after electrochemical preoxidation. When using 5 ml plasma the lower limit of detection is 40 pg/ml. Under routine conditions the limit of determination is determined to be 0.1 ng/ml. The variation coefficients drop from about 7% in the low range to about 4% at 5 ng/ml. The determination of trimethoquinol is not impaired by its monomethylated metabolites.     

Determination of verapamil and norverapamil in human biological material. Investigation of plasma concentrations after oral administration of two different verapamil formulations

A method for the simultaneous determination of the cardiovascular agent verapamil and its major metabolite norverapamil in human plasma is described. Analysis is performed after alkaline extraction with n-heptane by subsequent ion-paired high performance liquid chromatographic (HPLC) separation, and direct fluorimetric measurement of both compounds (lambda maxex. = 278 nm, lambda maxem. = 320 nm). The sensitivity of the procedure (detection limit less than 1 ng/ml) is suitable for pharmacokinetic studies after therapeutic doses. The applicability of the method was tested by performing a clinical study. Plasma concentrations of two verapamil formulations for oral administration were examined. The active metabolite norverapamil was included in the investigation.     

反相高效液相色谱-荧光法测定人血浆中维库溴铵的浓度

目的:建立以反相高效液相色谱-荧光法测定人血浆中维库溴铵浓度的方法。方法:色谱柱为Shim-pakCLC-ODS,流动相为1,4—二氧六环-0.1mol/L磷酸二氢钠∶0.11mol/L庚烷磺酸钠缓冲液(20∶80),样品提取分离后用流动相溶解,在Ex/Em=380/452nm波长处检测。结果:维库溴铵检测浓度在20~200ng/ml范围内线性关系良好(r=0.9995),最低检测浓度为10ng/ml(S/N=10),绝对回收率在98.63%~99.81%之间,方法回收率在98.83%~102.13%之间,日内、日间变异系数均小于10%。结论:本方法简便、稳定、灵敏,可满足临床药动学研究的需要。     

高效液相色谱法测定法莫替丁的血药浓度

目的 :建立HPLC法测定法莫替丁的血药浓度。方法 :采用Nova_PakC18(3 9×150mm ,5μm )色谱柱 ,柱温35℃ ;乙腈 -醋酸铵缓冲液 (6∶94)为流动相 ;流速1 1ml/min ;检测波长266nm。血浆样品经液 -液萃取处理。结果 :法莫替丁的血药浓度在12 5～300ng/ml范围内 ,与其峰面积有良好的线性关系 (γ=0 9996)。最低检测浓度8ng/ml ,方法的平均回收率102 39 % ,日内精密度≤5 00 % ,日间精密度≤6 59 %。结论 :该方法灵敏、准确、经济 ,可用于法莫替丁的药代动力学及生物利用度研究。     

Internally standardized determination of anipamil in human plasma by means of high-pressure liquid chromatography

A high pressure liquid chromatographic method with internal analogue standardization for the determination of anipamil in plasma is described. The method comprises extraction from plasma diluted with citrate buffer pH 3 using n-heptane/isoamylalcohol (95/5, v/v), distribution between this organic phase and a methanol/citric acid mixture, and quantification by means of fluorescense detection after HPLC separation using a reverse phase. When using 1 ml plasma the lower limit of detection is 0.2 ng/ml. Under routine conditions the limit of determination is estimated at 1 ng/ml, with higher numbers of replicates and with a predetermined precision limit of 15% concentrations as low as 0.6 ng/ml can be determined reliably. The variation coefficients drop from about 10% in the low range to about 5% at 2 ng/ml or more. The determination of anipamil is not impaired by its N-nor-compound, which is to be expected as metabolite. Neither do other potential metabolites of anipamil with very similar chromatographic behaviour interfere with its quantification.     

Development an ion-pair liquid chromatographic method for determination of sotalol in plasma using a monolithic column

A rapid and sensitive ion-pair HPLC method using a monolithic column and fluorescence detection has been developed for quantification of sotalol in plasma. The assay enables the measurement of sotalol for therapeutic drug monitoring with a minimum quantification limit of 10 ng ml(-1). The analytical method involves simple, one-step protein precipitation and no extraction procedure is needed. Sample preparation is fast and the analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 mm x 4.6 mm) column at ambient temperature. The mobile phase was 10% acetonitrile, 0.001 M heptane sulfonic acid, 0.02 M sodium dihydrogen phosphate, and distilled water to 100%, adjusted to pH 5.5 at a flow rate of 1.8 ml/min. The excitation wavelength was set at 235 nm, emission at 300 nm. The calibration curve was linear over the concentration range 20-1500 ng ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 7%. The method has been applied to the determination of sotalol in plasma from 12 subjects dosed with racemic sotalol.     

Internally standardized method for the determination of nalbuphine in human plasma by means of high performance liquid chromatography with electrochemical coulometric detection

A high performance liquid chromatographic method with internal analogue standardization and electrochemical detection for the determination of nalbuphine in human plasma is described. Using 3 ml plasma the lower limit of detection is below 50 pg/ml, during the routine assay the limit of determination can be fixed at about 250-300 pg/ml. The calibration curve is linear in the range between 0.163-65 ng/l, the recovery rate from plasma exceeds 80%. The method was successfully applied in several pharmacokinetic studies.