Experience with Quantitative Thin-Layer Chromatography in the Analysis of Drugs in Plasma

Abstract

A survey is presented concerning the possible techniques of quantitative thin-layer chromatography. Most of the possibilities mentioned have been used successfully in our laboratory for the determination of drugs and metabolites in plasma. With respect to our own experience, the advantages and disadvantages of quantitative thin-layer chromatography are discussed.

Although gas chromatography and high-performance liquid chromatography are more popular, quantitative thin-layer chromatography has a high potential in the analysis of drugs in samples of biological origin and should not be neglected in the development of an assay.     

Labetalol Analysis in Human Plasma Using Liquid Chromatography with Electrochemical Detection: Application to Pharmacokinetic Studies

Abstract

Labetalol determination in human plasma by a sensitive (to 2.5 ng/ml) and selective method using liquid chromatography with electrochemical detection is described. Plasma is extracted with diethyl ether under mildly basic (pH 9) conditions, back-extracted into an aqueous acidic buffer, then injected directly on column. Standard curves using propranolol as an internal standard are linear for concentrations from 2.5 to 200 ng/ml. Within-day and between-day reproducibility is satisfactory with coefficient of variation less than 8% for all concentrations. Sample recovery from the extraction is complete at all concentrations. Utility of the method is demonstrated by a pharmacokinetic study in a hypertensive volunteer who received 43.75 mg labetalol by 10 minute intravenous infusion.     

Determination of Biphenyl in Citrus Fruits by Quantitative Thin-Layer Chromatography

Abstract

Residues of the fungicide biphenyl in citrus fruits have been determined by direct scanning of spots on phosphor-impregnated high performance silica gel TLC plates under UV light. Biphenyl was separated from fruit tissue by steam liquid-liquid extraction. Recoveries from spiked samples ranged from 92–99% at 100, 50, and 10 ppm levels. The precision of the TLC determination and overall procedure are shown to be adequate for residue analysis.     

Analysis of PCB's by Thin-Layer Chromatography

Abstract

A screening thin layer chromatography (TLC) technique has been developed that can be done in the field. Quantitative analysis by TLC densitometry can be done in a laboratory (or field van). A densitometer is needed for quantitative work by TLC. An Apple computer may be added to use as a computational device. Semi-quantitative results may be obtained by visual comparisons. Confirmations may be made by silver halide visualization on TLC. Dehalogenation with sodium biphenyl, chlorination with antimony pentachloride, or mass spectral confirmation may be used. Quantitative analysis is possible of the derivatized positive samples.     

Pharmacokinetic Analysis of Ursolic Acid in Alstonia scholaris R. Br. by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A simple and rapid high-performance thin-layer chromatographic method has been established and validated for determination of...     

Quantitative Determination of Propranolol in Human Serum by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method for the quantification of propranolol in human serum is developed and...     

大豆磷脂组成的薄层色谱分析

采用国产硅胶板和二次展开的薄层色谱法，对具有重要的生物功能的大豆磷脂组成进行了分析，获得了大豆磷脂中１１个重要组分的定性结果。用已知样品量的薄层光密度扫描方法建立了卵磷脂定量方法，线性关系良好，并用于实际样品的测定，获得了满意结果。     

蔗糖酯的薄层分析

 以硅胶G板为固定相、甲苯 乙酸乙酯 甲醇 水 (体积比为 1 0∶5∶4 5∶0 2 )为流动相 ,研究建立了蔗糖酯薄层分析方法。在蔗糖酯上行展开后 ,用脲 磷酸 水饱和正丁醇溶液显色 ,斑点呈蓝色 ,蔗糖单酯的Rf 值为 0 1 6 ,多酯的Rf 值为 0 38～ 0 93。在 70℃显色 2 0min的最佳条件下 ,蔗糖单酯的检测量为 2 5 μg～ 2 50 μg时 ,其斑点面积与其检测量有良好的线性关系。用归一法和外标法对该分析方法的准确度进行考察和认证 ,两种方法对已知单酯含量的S 1 570样品测定结果的t 检验结果分别为 |t| =0 62 7(<2 571 )和 |t|=1 1 2 3(<2 571 ) 。     

Analysis of Bromo-DragonFLY by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

The Application of Cross-Scanning to Conventional Thin-Layer Chromatography

Abstract

The technique of cross-scanning, the scanning of thin-layer chromatographic (TLC) plates perpendicular to the direction of development, is applicable to conventional quantitative TLC where significant advantages over normal scanning are realized by its use. Several factors are discussed which influence the ability to cross-scan, such as application of the sample, solvent development and instrumentation.     

HPLC Determination of Letrozole in Plasma Using Fluorescence Detection: Application to Pharmacokinetic Studies

A simple, rapid and sensitive HPLC method has been developed and validated for the analysis of letrozole in human plasma. The separation was achieved on a monolithic silica column using acetonitrile–phosphate buffer. A fluorescence detector was used for the quantitation with excitation and emission wavelengths at 230 and 295 nm. The assay enables the measurement of letrozole for therapeutic drug monitoring with a minimum quantification limit (LOQ) of 0.5 ng mL^?1. The method involves a simple, one-step extraction procedure with complete recovery. Calibration was linear over the concentration range 0.5–80 ng mL^?1. The coefficients of variation for inter-day and intra-day assay were found to be less than 8%.     

Elucidation of Chemical Interactions between Crude Drugs Using Quantitative Thin-Layer Chromatography Analysis

To elucidate the interactions between crude drugs in Kampo medicines (traditional Japanese medicines), it is important to determine the content of the constituents in a cost-effective and simple manner. In this study, we quantified the constituents in crude drug extracts using thin-layer chromatography (TLC), an inexpensive and simple analytical method, to elucidate the chemical interactions between crude drugs. We focused on five crude drugs, for which quantitative high-performance liquid chromatography (HPLC) methods are stipulated in the Japanese Pharmacopoeia XVIII (JP XVIII) and compared the analytical data of HPLC and TLC, confirming that the TLC results corresponded with the HPLC data and satisfied the criteria of JP XVIII. (Z)-ligustilide, a major constituent in Japanese Angelica Root, for which a method of quantification has not been stipulated in JP XVIII, was also quantitatively analyzed using HPLC and TLC. Furthermore, Japanese Angelica Root was combined with 26 crude drugs to observe the variation in the (Z)-ligustilide content from each combination by TLC. The results revealed that combinations with Phellodendron Bark, Citrus Unshiu Peel, Scutellaria Root, Coptis Rhizome, Gardenia Fruit, and Peony Root increased the (Z)-ligustilide content. Quantifying the constituents in crude drug extracts using the inexpensive and simple TLC method can contribute to elucidating interactions between crude drugs in Kampo medicines, as proposed by the herbal-pair theory.     

血浆中辛伐他汀分析方法及药代动力学研究

采用ＧＣ／ＭＳ的ＳＩＭ定量模式,以洛伐他汀做内标,经乙酸乙酯萃取后,测定人体血中辛伐他汀的浓度。标准曲线在０．２７－５４μｇ／Ｌ之间呈良好的线性关系,ｒ〉０．９９９,高中低３个浓度点的日间日内ＲＳＤ小于５．２％,回收率可达９６％－１０３％〈并应用在１０例健康志愿者口服４０ｍｇ辛伐他汀的药代动力学的研究。     

Application of Multiple-Gradient Thin-Layer Chromatography for the Quantitative Determination of Convallatoxine in Herba Convallariae

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatographic method with densitometric detection has been used to determine the convallatoxine...     

Quantitative Determination of Digitalis Glycosides in Digitalis Purpurea Leaves by Reversed-Phase Thin-Layer Chromatography

Abstract

A densitometric reversed-phase thin-layer chromatographic(RP-TLC) method for the determination of digitalis glycosides in Digitalis purpurea leaves has been developed. The procedure involves extraction of dry leaf powder with ethanol/chloroform (2:1) and clean-up by Sep-Pak cartridges prior to RP-TLC analysis. RP-TLC was performed on an octadecylsilyl bonded silica gel plate, using a developing solvent of acetonitrile/0.5 M NaCl(1 : 1) for secondary glycosides and acetonitrile/0.5 M NaCl(2 : 3)for primary glycosides. The plate was scanned with a reflectance densitometer at 222 nm. Quantitation of these glycosides was carried out by the internal standard method. The amounts of digitoxin, gitoxin, gitaloxin, purpurea glycoside A, purpurea glycoside B, and glucogitaloxin in a leaf powder sample of Digitalis purpurea were estimated from the calibration graphs for pure glycosides.     

Analysis of Ebastine in Pharmaceutical Preparations by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

薄层色谱法分析葵花仁粕中的绿原酸

 以聚酰胺薄膜为固定相、体积分数为 36 %的乙酸溶液为流动相 ,研究建立了薄层色谱分离测定葵花仁粕中绿原酸的方法。绿原酸样品溶液上行展开 8 5cm ,其Rf 值为 0 6 1。绿原酸的检测量在 0 0 5 μg～ 0 6 μg范围内 ,其斑点的面积与绿原酸的检测量具有良好的线性关系。绿原酸的回收率为 97 5 3 % ,不同薄层板之间的RSD为2 5 7% ,最低检出限为 0 0 2 5 μg。在以体积分数为 70 %的乙醇溶液为萃取剂、搅拌振荡萃取时间为 30min的条件下 ,以该方法测定萃取液中绿原酸的含量和葵花仁粕中绿原酸的残留量 ,确定了最佳萃取次数。     

Analysis of Waxes on Historical Samples by Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Analysis of the composition of binders applied to different historical objects is an important analytical task. On the basis of the...     

Application of Image Analysis Technique for the Determination of Organophosphorus Pesticides by Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A simple and convenient thin-layer chromatography (TLC) method combined with image analysis technique was developed to determine...