The quantitative detection of estrogens and antithyroid drugs by thin-layer and high performance thin-layer chromatography in animal tissue (author's transl)]

Methods of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) were developed for the determination of estrogens and antithyroid drugs in extracts of animal tissues. TLC proved to be suitable for quantities in the range of 200-2000 ng, with a detection limit of 50-200 ng, HPTLC in the range of 10-200 ng, showing calibration curves of good linearity even in extracts. By HPTLC better detection limits, better separation and faster ascending could be achieved than by TLC.     

Application of sorbent extraction chromatography to the purification of diethylstilboestrol extracted from muscle tissue and determined by radioimmunoassay

A chromatographic procedure is described for the purification of bovine muscle tissue extracts prior to the determination of diethylstilboestrol (DES) by radioimmunoassay. Sorbent extraction chromatography of tissue extracts on reversed-phase octadecyl (C18) columns gives adequate recovery of residue and a suitable sample for radioimmunoassay. This procedure, which is simple and rapid, provides an alternative to a more complex purification by high-performance liquid chromatography. Using this method, the limit of detection for DES in muscle samples is approximately 40 pg/g.     

Comparison between thin-layer chromatography and overpressured layer chromatography fingerprints of commercial essential oils and accelerated solvent extraction plant extracts

Developing fit-to-purpose analytical screening methods for plant marker constituents by simple and affordable techniques represents a constant and important request from the current transformation chain of plant products. In this work, methods developed on classical thin-layer chromatography (TLC) and overpressured layer chromatography (OPLC) have been applied on some of the most valuable commercial plant products, such as star anise (Illicium verum Hook. f.) essential oil and extracts, common thyme (Thymus vulgaris L.) and sweet fennel (Foeniculum vulgare Mill.) essential oils and acerola fruit (Malpighia punicifolia L.) hydroalcoholic extracts, to evaluate OPLC potentiality in comparison with TLC performances in the detection of some characteristic constituents. OPLC provided higher performance with respect to TLC in all experiments performed due to higher selectivity demonstrated on all the tested marker compounds except for flavonoids in acerola extracts. Considering the usage of planar chromatography in the quality control of plant derivatives, the present paper shows how the OPLC protocols were both highly time- and solvent-saving in comparison with classical TLC.

     

Development and validation of a simple thin layer chromatographic method for the analysis of artemisinin in Artemisia annua L. plant extracts

Owing to the development of parasite resistance to standard antimalarial treatments like chloroquine and sulfadoxine-pyrimethamine, the demand for Artemisia annua, a key ingredient for new and highly effective antimalarial drugs, is huge. Therefore selective and precise methods to determine the content of artemisinin in dry plant material and in raw impure extracts are needed. In this work a method is described for the clear separation and extraction of artemisinin from other plant components in the Artemisia annua L. plant by thin-layer chromatography (TLC). To obtain optimal extraction and recovery efficiency, several parameters were evaluated, including choice of extraction solvent, TLC plate type and sensitivity between UV and visible light. Method validation was performed on both the dry plant material and non-purified plant extracts. Toluene presented the highest extraction efficiency compared with petroleum ether, hexane and methanol. Reversed-phase plates showed more concentrated spots than normal-phase plates, while the sensitivity of the analysis in UV was comparable to that in visible light but less precise. The impure plant extracts were analyzed by both TLC and HPLC-UV at 215 nm and both methods met the requirements for linearity, selectivity, precision and accuracy. Hence, the proposed TLC method can easily be used for both qualitative and quantitative control of the raw plant extract in areas where advanced methods are scarce.     

TLC fingerprint of phenolics and saponins in commercial extracts of Yucca schidigera Roezl.

Yucca schidigera Roezl. (yucca) is one of the major industrial sources of steroid saponins approved by the Food and Drug Administration (FDA) as generally recognized as safe. Due to the increasing applications of yucca extracts, there is a need for a simple, low-cost method for the authentication of samples. This paper presents a method to obtain unique fingerprints of commercial products of yucca using a single-thin layer chromatography (TLC) system and two visualization reagents for the detection of phenolics and saponins, as a tool for the preliminary quality assessment of the products.     

TLC of alkaloids on cyanopropyl bonded stationary phases. Part II. Connection with RP18 and silica plates

Some standards of the alkaloids and synthetic or natural mixtures are separated by two-dimensional thin-layer chromatography (TLC) on different adsorbent layers. Normal- and reversed-phase systems are used to obtain significant differences in the separation selectivity. Optimization of the one-dimensional TLC separation of the alkaloids' standards is performed on cyanopropyl-silica, RP18W, and silica layers in various eluents containing (besides diluent and modifier) silanol blockers, such as diethyl amine or ammonia. The most selective systems are used for the separation of the alkaloids' mixtures by two-dimensional TLC with an adsorbent gradient method. The mixtures of alkaloids or plant extracts (Chelidonium majus, Fumaria officinalis, or Glaucium flavum) are chromatographed in system I; the plates are connected with the plate pre-coated with various adsorbent, and partly separated fractions are transferred to the second layer and developed in system II. CN-silica-RP18W and CN-silica-silica are used as the connected layers. The alkaloids are identified by R(F) values of standards, and the components of plant extracts are identified in both systems, and by the comparison of UV spectra obtained in diode array detector densitometry.     

Application of a capillary gas chromatographic-selected-ion recording mass spectrometric technique to the analysis of diethylstilbestrol and its phosphorylated precursors in plasma and tissues

A method for the analysis of diethylstilbestrol (DES) which is suitable for pharmacokinetic studies has been developed using capillary gas chromatographic (GC) separation and detection with selected-ion mass spectrometry (MS). This technique has been applied to a variety of samples including human plasma samples and extracts of animal tissues including prostate and liver. To investigate the pharmacokinetics of stilphostrol (diethylstilbestrol diphosphate) we have modified the GC-MS method in two ways. One modification involves a dual assay for DES; the first a direct assay, and the second after hydrolysis of a sample with alkaline phosphatase. The difference in these values is the amount of phosphorylated DES present. The other modification separates stilphostrol and DES using a reversed-phase, ion-paired high-performance liquid chromatographic method followed by alkaline phosphatase hydrolysis followed by the GC-MS method. The details of these three methods are described and some representative data are shown.     

Identification and Quantitative Determination of Nabumetone in Pharmaceutical Preparations by TLC-Densitometry

JPC – Journal of Planar Chromatography – Modern TLC - A simple, selective, and sensitive thin-layer chromatography (TLC) method is described for the identification and determination of...     

Determination of Diethylstilbestrol in Aquatic Products by High Performance Liquid Chromatography with Fluorescence Detection

A sensitive method for the determination of diethylstilbestrol (DES) in aquatic products by high performance liquid chromatography (HPLC) using a fluorescence detector (FLD) was developed. By means of sulfonation in concentrated sulfuric acid and hydrolysis, DES was converted into a reaction product that can emit fluorescence and determined by HPLC. For the first time, HPLC with FLD was applied to the determination of DES and sensitivity comparable to that of LC‐MS gained. The limit of detection was 0.1 µg·kg^?1, and the recoveries were above 86% with relative standard deviations less than 6.2%. The proposed method was successfully applied to the determination of DES in aquatic products.     

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.     

Screening for acetylcholinesterase inhibitors from Amaryllidaceae using silica gel thin-layer chromatography in combination with bioactivity staining

Thin-layer chromatography (TLC) was used to screen for acetylcholinesterase inhibitors from Amaryllidaceae extracts. The TLC plate was developed and then stained using Ellman's reagent, 5,5'-dithiobis-(2-nitrobenzoic acid), to detect acetylcholinesterase activity. The advantages of this TLC assay method were that we could dereplicate the known inhibitor galanthamine, widely occurring in Amaryllidaceae, at an early stage of the isolation procedure. Moreover, there is no disturbance from sample dissolving solvents as in the microplate assay, and it is a very simple method. The detection limits were 10-200 ng for several known acetylcholinesterase inhibitors tested, and it is thus more sensitive than UV or Dragendorff's reagent detection. Also the minimal detectable amount for an acetylcholinesterase inhibitor tested was much less than that needed for the microplate assay. We screened 15 Amaryllidaceae extracts using this TLC method, and chose candidates for acetylcholinesterase inhibitor isolation.     

Development and Validation of a Stability-Indicating Assay Method for Naftopidil

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, selective, precise, and stability-indicating high-performance thin-layer chromatography (HPTLC) method for the...     

Determination of Flavonoids in Tea and Rooibos Extracts by TLC and HPLC

JPC – Journal of Planar Chromatography – Modern TLC - In this study thin-layer chromatography (TLC) was used for analysis of the constituents of extracts of tea (Camellia sinensis L.)...     

Stability-Indicating HPTLC Method of Carteolol in Bulk Drug and in Pharmaceutical Dosage Forms

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatography (HPTLC) method was developed...     

Validated HPTLC Method for Simultaneous Determination of Loratadine and Desloratadine in Presence of Co-Formulated Drug

JPC – Journal of Planar Chromatography – Modern TLC - A highly validated and selective high performance thin layer chromatography (HPTLC) method was developed for the determination of...     

Development and Validation of a High-Performance Thin-Layer Chromatographic Method for the Assay of Ternary Mixtures Containing Cetirizine Dihydrochloride in Pharmaceutical Dosage Forms

JPC – Journal of Planar Chromatography – Modern TLC - A highly validated and selective high-performance thin-layer chromatography (HPTLC) method was developed for the determination of...     

Selective separation and simultaneous determination of trace levels of five types of fluorinated quinolone drugs by thin-layer chromatography/fluorescence densitometry.

This paper reports the determination of trace levels of 5 types of fluorinated quinolone drugs, i.e., ciprofloxacin, norfloxacin, enoxacin, pefloxacin, and ofloxacin, by thin-layer chromatography (TLC)/fluorescence densitometry. The new analytical method uses 2-step TLC development, selective separation, and simultaneous determination of the 5 drugs. The method was also applied to the determination of recoveries of standards of the 5 drugs in plasma and urine samples. The results show that the method has a wide linear range, high repeatability, and good stability.     

High-Performance Thin-Layer Chromatography for the Simultaneous Determination of Co-administrated Granisetron,Aprepitant, and Deflazacort Used with Chemotherapy: Application onto Dosage Forms and Spiked Plasma by Liquid—Liquid Extraction

JPC – Journal of Planar Chromatography – Modern TLC - A selective and economic high-performance thin-layer chromatography (HPTLC) method has been developed for the simultaneous...     

A versatile high-performance thin-layer chromatographic method for the simultaneous determination of five antihypertensive drugs: method validation and application to different pharmaceutical formulations

JPC – Journal of Planar Chromatography – Modern TLC - A selective high-performance thin-layer chromatography (HPTLC) densitometric method has been developed for the simultaneous...     

Densitometric HPTLC Analysis of Juglone,Quercetin, Myricetin,Rutin, Caffeic Acid,and Gallic Acid in Juglans regia L.

JPC – Journal of Planar Chromatography – Modern TLC - Asensitive, selective, and precise high-performance thin-layer chromatography (HPTLC) method was developed for simultaneous...