Adsorption Thin-layer Chromatography Research Articles

Application of HPTLC with Densitometry for Evaluation of the Impact of External Factors on Contents of Diphenhydramine in Its Solutions.

The subject of durability of drugs is a very important problem investigated by researches. The method of accelerated aging is very often used for stability testing. It involves the influence of temperature, humidity, and light exposure. The aim of this work is estimation of contents of diphenhydramine in its standard solutions undergoing the impact of external factors, that is, temperature and UV light. The standard solutions of diphenhydramine were prepared in distilled water. The analysis of contents of compound investigated was carried out by use of HPTLC. Adsorption thin layer chromatography was performed on aluminum HPTLC plates precoated with silica gel 60F254 using mixture of ammonia, methanol, and ethyl acetate as mobile phase. The solutions investigated were exposed to UV light as well as being heated in 40°C. The contents of diphenhydramine were measured in initial solution and during experiment. The additional peaks on densitograms as well as changes in color of solution were observed as a result of exposure to UV light which can give information about new substances, degradation products of diphenhydramine, which were created during experiment.

The use of similarity analysis for evaluation of the chromatographic separation of salicylic acid and its selected derivatives studied by adsorption and partition thin-layer chromatography techniques

The aim of the work was the chromatographic separation of salicylic acid and their derivatives, i.e., acetylsalicylic acid, salicylanilide, salicylaldehyde, salicylamide, methyl salicylate, phenyl salicylate, 2,5-dihydroxybenzoic acid, salicylhydroxamic acid, 3,5-dinitrosalicylic acid, 3-aminosalicylic acid, 4-aminosalicylic acid, and 5-aminosalicylic acid by use of adsorption thin-layer chromatography (normal-phase thin-layer chromatography [NPTLC]) and partition thin-layer chromatography (reversed-phase thin-layer chromatography/high-performance thin-layer chromatography [RP-TLC/HPTLC]). Three qualitatively and quantitatively different mobile phases were used for the separation of salicylic acid and its derivatives. Cluster analysis (single linkage method, Euclidean distance) allowed the evaluation of the suitability of the chromatographic conditions used to separate the pairs of tested compounds. The cluster analysis data indicate that the composition of the mobile phase is fundamental in the process o...

COMPARISON OF THE DETECTION AND QUANTITATIVE LIMITS OF HYDROCORTISONE ACETATE IN DIFFERENT CHROMATOGRAPHIC CONDITIONS IN TLC

The detection (LOD), and quantification limits (LOQ) of hydrocortisone acetate in different conditions in TLC have been compared. Analysis has been performed using adsorption thin layer chromatography (NP-TLC) on chromatographic plates precoated with aluminum oxide 60 F254, aluminum oxide 150 F254, silica gel 60, silica gel 60 F254, a mixture of silica gel, and kieselguhr 60 F254 using chloroform + acetone + ammonia (25%) (8:2:0.1, v/v/v), and toluene + ethyl acetate (15:35, v/v) as well as reversed phase thin layer chromatography (RP-TLC) on the plates precoated with silica gel RP18 F254, silica gel RP8 F254 using the mixture of methanol + water in volume compositions 6:4 and 7:3. It has been proved that the stationary and mobile phase have a significant influence on the values of the detection limit (LOD), and quantification (LOQ) of hydrocortisone acetate in adsorption and partition thin layer chromatography. Using NP-TLC technique, the least amount of hydrocortisone acetate was detected and determined on plates precoated with aluminum oxide 150 F254, and silica gel 60 using chloroform + acetone + ammonia (25%) in volume compositions 8:2:0.1 as a mobile phase. By means of RP-TLC technique, the least amount of hydrocortisone acetate was detected and determined on plates precoated with silica gel RP8 F254. The detection limit (LOD) of hydrocortisone acetate determined by both TLC methods in nanogram range (51 ÷ 137 ng · spot−1) indicates that thin layer chromatography combined with densitometry may be an alternative method to the modern chromatographic techniques for hydrocortisone acetate detection.

USE OF TLC FOR THE QUANTITATIVE DETERMINATION OF ACETYLSALICYLIC ACID, CAFFEINE, AND ETHOXYBENZAMIDE IN COMBINED TABLETS

Adsorption thin layer chromatography (NP-TLC) with densitometry has been established for the identification and the quantification of acetylsalicylic acid, caffeine, and ethoxybenzamide in combined tablets. UV densitometry was performed in absorbance mode at 200 nm, 275 nm, and 300 nm for acetylsalicylic acid, caffeine, and o-ethoxybenzamide, respectively. The presented method was validated by specificity, range, linearity, accuracy, precision, detection limit, quantitative limit, and robustness. It could be said that the NP-TLC-densitometric method is suitable for the routine analysis of acetylsalicylic acid, caffeine, and ethoxybenzamide in combined tablets in quantity control laboratories.

Validation Thin Layer Chromatography for the Determination of Acetaminophen in Tablets and Comparison with a Pharmacopeial Method

Adsorption thin layer chromatography (NP-TLC) with densitometry has been established for the identification and the quantification of acetaminophen in three leading commercial products of pharmaceutical tablets coded as brand: P1 (Product no. 1), P2 (Product no. 2), and P3 (Product no. 3). Applied chromatographic conditions have separated acetaminophen from its related substances, namely, 4-aminophenol and and 4′-chloroacetanilide. UV densitometry was performed in absorbance mode at 248 nm. The presented method was validated by specificity, range, linearity, accuracy, precision, detection limit, quantitative limit, and robustness. The TLC-densitometric method was also compared with a pharmacopeial UV-spectrophotometric method for the assay of acetaminophen, and the results confirmed statistically that the NP-TLC-densitometric method can be used as a substitute method. It could be said that the validated NP-TLC-densitometric method is suitable for the routine analysis of acetaminophen in quantity control laboratories.

DETERMINATION OF ACETYLSALICYLIC ACID IN PHARMACEUTICAL DRUGS BY TLC WITH DENSITOMETRIC DETECTION IN UV

Adsorption thin layer chromatography (NP-TLC) with densitometry has been established for the identification and the quantification of acetylsalicylic acid in tablets. UV densitometry was performed in absorbance mode at 200 nm. The presented method was validated by specificity, range, linearity, accuracy, precision, detection limit, quantitative limit, and robustness. The TLC-densitometric method was also compared with a pharmacopeial UV-spectrophotometric method for the assay of acetylsalicylic acid, and the results confirmed statistically that the NP-TLC-densitometric method can be used as a substitute method. It could be said that the NP-TLC-densitometric method is suitable for the routine analysis of acetylsalicylic acid in quantity control laboratories.

VALIDATION THIN LAYER CHROMATOGRAPHY FOR THE DETERMINATION OF NAPROXEN IN TABLETS AND COMPARISON WITH A PHARMACOPEIL METHOD

Adsorption thin layer chromatography with densitometry has been established for the identification and the quantification of naproxen in tablets. UV densitometry was performed in absorbance mode at 230 nm. The presented method was validated by specificity, range, linearity, accuracy, precision, detection limit, quantitative limit, and robustness. The TLC-densitometric method was also compared with a pharmacopeial UV-spectrophotometric method for the assay of naproxen, and the results confirmed statistically that the TLC-densitometric method can be used as a substitute method.

DETERMINATION OF HYDROCORTISONE IN PHARMACEUTICAL DRUG BY TLC WITH DENSITOMETRIC DETECTION IN UV

Adsorption thin layer chromatography with densitometry has been established for the identification and the quantification of hydrocortisone in tablets. UV densitometry was performed in absorbance mode at 250 nm. The presented method was validated by specificity, range, linearity, accuracy, precision, detection limit, quantitative limit, and robustness. The TLC-densitometric method was also compared with a pharmacopeil UV-spectrophotometric method for the assay of hydrocortisone, and the results confirmed statistically that the TLC-densitometric method can be used as a substitute method.

Effect of the structure of selected metalloporphyrins on their chromatographic properties

We have determined the effect of the structure of selected metalloporphyrins on their chromatographic properties. Separations of tetraphenylporphyrin and its Cu(II) and Ni(II) derivatives were compared in adsorption and partition thin-layer chromatography. We determined the molecular structure of tetraphenylporphyrin complexes by magnetic studies and compared the structures obtained with the aid of molecular modeling.

Chiral Separations of Ibuprofen and Propranolol by TLC. A Study of the Mechanism and Thermodynamics of Retention

In contrast with gas and column liquid chromatography, both of which enable very efficient separation of enantiomers, thin‐layer chromatography (TLC) has never proved particularly successful in the same field. This can be regarded as puzzling because although the performance of TLC is substantially lower than that of the instrumental modes of chromatography, it still seems efficient enough to ensure even difficult separations of pairs of analytes. There is a steady demand for simple, inexpensive, and successful chiral separations, preferably executed with the aid of TLC. The best proof of this is a few documented and promising attempts reported by reliable laboratories in developing countries. Some of these reports, however, describe experiments performed with glass plates coated in the laboratory, which gives rise to questions regarding the accuracy and repeatability of the results obtained. Similar concerns are evoked by traditional visualization of the outcome of a separation by use of dyeing agents, rather than by densitometry (which furnishes concentration profiles of the bands and the possibility of in‐situ identification also). In this study, we have repeated chiral separations of two widely used drugs, ibuprofen and propranolol, adapting working conditions reported elsewhere to a system based on standardized and commercially available chromatographic plates. We also performed detection and identification on the developed chromatograms by means of densitometry. In our experiments with the modified chromatographic procedures, the results obtained proved at least as good as those reported in the original papers and occasionally somewhat better. For both ibuprofen and propranolol, preliminary thermodynamic evaluation of the standard chemical potentials of adsorption (Δμa) for each of the two enantiomers considered was also performed. The results obtained look promising and realistic; it seems that adsorption TLC can be used in the future for thermodynamic assessment of the racemization process.

Separation of Selected Bile Acids by TLC. VIII. Separation on Silica Gel 60F254 Glass Plates Impregnated with Cu(II), Ni(II), Fe(II), and Mn(II) Cations

The aim of our study was to examine the following bile acids: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC). In the present study, to separate a/m bile acids using adsorption thin layer chromatography at 18°C, the glass plates precoated with silica gel 60F254 (#1.05715), were impregnated with 1%, 2.5%, and 5% aqueous solutions of the following salts: CuSO4, MnSO4, NiSO4, and FeSO4. The mixtures of n‐hexane–ethyl acetate–acetic acid in the volume compositions: 22:20:5; 25:20:2; 25:20:5, and 25:20:8 were used as mobile phases. These mobile phases were not effective for the separation of bile acids on non impregnated silica gel 60F254 plates at 18°C. The plates impregnated with the salts whose application resulted in ΔRF≥0.05 and RS>1 for all neighboring pairs of examined bile acids were considered the most effective for bile acids separation. It was observed that impregnation of silica gel 60F254 glass plates with aqueous solutions of CuSO4, MnSO4, NiSO4, and FeSO4 improved the separation of GC/GDC and C/GLC, which separated poorly on glass plates precoated with non impregnated silica gel 60F254 in adsorption TLC at 18°C.

Physicochemical and physiological properties of 5α-cyprinol sulfate, the toxic bile salt of cyprinid fish

5alpha-Cyprinol sulfate was isolated from bile of the Asiatic carp, Cyprinus carpio. 5alpha-Cyprinol sulfate was surface active and formed micelles; its critical micellization concentration (CMC) in 0.15 M Na+ using the maximum bubble pressure device was 1.5 mM; by dye solubilization, its CMC was approximately 4 mM. At concentrations >1 mM, 5alpha-cyprinol sulfate solubilized monooleylglycerol efficiently (2.1 molecules per mol micellar bile salt). When infused intravenously into the anesthetized rat, 5alpha-cyprinol sulfate was hemolytic, cholestatic, and toxic. In the isolated rat liver, it underwent little biotransformation and was poorly transported (Tmax congruent with 0.5 micromol/min/kg) as compared with taurocholate. 5alpha-Cyprinol, its bile alcohol moiety, was oxidized to its corresponding C27 bile acid and to allocholic acid (the latter was then conjugated with taurine); these metabolites were efficiently transported. 5alpha-Cyprinol sulfate inhibited taurocholate uptake in COS-7 cells transfected with rat asbt, the apical bile salt transporter of the ileal enterocyte. 5alpha-Cyprinol had limited aqueous solubility (0.3 mM) and was poorly absorbed from the perfused rat jejunum or ileum. Sampling of carp intestinal content indicated that 5alpha-cyprinol sulfate was present at micellar concentrations, and that it did not undergo hydrolysis during intestinal transit. These studies indicate that 5alpha-cyprinol sulfate is an excellent digestive detergent and suggest that a micellar phase is present during digestion in cyprinid fish.

Adsorption thin-layer chromatography and viscometry of polystyrenes in solvent mixtures

The effect of the thermodynamic quality of solvent mixtures on the adsorption behavior of macromolecules under dynamic conditions was investigated. The chromatographic behavior of polystyrenes (PSs) in various mixed eluents was studied under conditions of adsorption and size-exclusion thin-layer chromatography as well as at the exclusion–adsorption transition point with silica gel KSKG adsorbent. The thermodynamic quality of the solvent mixtures used in the chromatographic experiments was determined viscometrically. The dependences of the intrinsic viscosity of PSs on solvent composition for solvent–non-solvent, two solvents, and θ-solvent–solvent mixtures were obtained. A correlation was found between Snyder’s polarity indices for the solvent mixtures used in polymer chromatography under “critical conditions” and the intrinsic viscosity values of PSs in the same mixtures.

Silver Ion Adsorption Thin Layer Chromatography and Capillary Gas Chromatography in the Study of the Composition of Milk Fat Triglycerides

Fatty acid and triglyceride (TG) composition of milk fat and of the six fractions obtained by AgNO3-TLC were determined using capillary GC. The saturated (SSS) and monounsaturated (SSM) TGs accounted with two fractions each that were separated into butyrates and all the others; the remaining fractions were identified as di- and triunsaturated TGs, respectively. The total TGs and the SSM were distributed in similar proportions with respect to chain length. The molar percentages of SSS in short- and medium-chain TGs (60.2 and 45.0%, respectively) were higher than those of polyunsaturated TGs (11.5 and 21.6%, respectively). Most of the peaks found in the chromatogram of milk fat TGs were located predominantly in one of the AgNO3-TLC fractions. Thirty-seven peaks were >1%; from the most important in quantitative terms, six (three SSS and three SSM) contain butyric acid and four contain three long-chain fatty acids. Eighty-one molecular species of TGs were identified. Keywords: Milk fat; triglycerides; molecular classes; molecular species; silver ion adsorption TLC; capillary GC

Purification of antibiotics produced byLentinus squarrosulus and preliminary characterization of a compound active againstRigidoporus lignosus

Purification and study of the antibiotic substances produced byLentinus squarrosulus have been carried out. The substances, excreted in the culture medium, were extracted withn-butanol. The butanolic extract inhibited growth ofRigidopurus lignosus, the agent of white rot ofHevea brasiliensis, and also ofMucor ramannianus, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, andBacillus subtilis. The antibiotic fractions were purified by silicic acid column chromatography, then by reversed-phase (C18) high performance liquid chromatography (HPLC) followed by preparative adsorption thin-layer chromatography on silica gel. Two purified compounds were obtained: Ls1, which was active againstB. subtilis, and Ls2, which in addition was also active againstR. lignosus, M. ramannianus, and yeasts. Only the Ls2 compound is analyzed in this work. It was characterized by chemical reactions, ultraviolet spectroscopy, infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy, which indicated the hydrophilic character of the molecule and the presence of alcoholic functions as well as a glycosidic moiety. The properties differed from those of already known antibiotics produced by different species ofLentinus.

Thin-layer chromatographic detection of glucocorticoids.

An adsorption thin-layer chromatography (TLC) is described for the detection of glucocorticoids including triamcinolone, prednisolone, 6 alpha-methylprednisolone, betamethasone, dexamethasone, hydrocortisone, prednisone and cortisone. Separation of the glucocorticoids was performed on a silica stationary phase with chloroform-dioxane-methanol (15:4:1, v/v) as a mobile phase. The complete resolution of the epimers of betamethasone and dexamethasone was attained by derivatization of them with (1S)-(-)-camphanic chloride using triethylamine as a catalyst. The application of the method to the analysis of glucocorticoids in various samples is being smoothly developed.

Identification of individual diacylglycerols by adsorption thin-layer chromatography of their coordination complexes

Diacylglycerols (DAGs) obtained by glycerolysis of a mixture of cocoa butter, poppy seed and linseed oils were separated by preparative thin-layer chromatography (TLC) into their positional isomers. An isomerically pure model mixture of rac-1,2-DAGs was further separated into eleven fractions using adsorption TLC of coordination complexes of unsaturated DAGspecies with silver ions on an analytical scale. The mobility of the separate TLC zones of this mixture, which included residues of stearic (St), palmitic (P), oleic (O), linoleic (L) and linolenic (Le) acids, was compared with that of standard rac-1,2-DAG zones. The comparison demonstrated that the model mixture was composed of the following individual DAG species: StO-, PO-, OO-, OL-, LL-, OLe-, LLe- and LeLe-glycerols, in addition to SS-, SL- and SLe-glycerols in which S is St or P. The different mobilities of these DAG species can be accounted for by the differences in the relative polarities of the Ag + complexes of O, L and Le, which were found to be 1.03, 2.46 and 5.45, respectively. There was a strong negative correlation between the mobility and the polarity of the DAG species.

Analysis of Chromatographic Parameters in the Systems with Ternary Mobile Phases. II. Two Polar Solvents in Mobile Phase

Abstract The experimental data are presented on Gibbs triangles in the form of isolines. The effect of change of the type of two polar mobile phase components on the chromatographic parameters of model substances has been investigated. The presence of alcohol in ternary mobile phase leads to formation double or “closed” RF isolines on Gibbs triangles. Such presentation of the experimental data allowed to complex analysis of the chromatographic process in systems with ternary mobile phase. The measurements were made by adsorption thin layer chromatography on silica gel at temperature 293 K.

Analysis of Chromatographic Parameters in the Systems with Ternary Mobile Phases

Abstract A new method is proposed for analysis of chromatographic parameters obtained for ternary mobile phases. The experimental data are presented in Gibbs triangle in the form of isolines i.e. lines connecting the points corresponding to the same chromatographic parameters values. The measurements were made by adsorption thin layer chromatography technique on silica gel at temperature 293 K. After the analysis of the isolines obtained in this way a new method for optimal choosing of the mobile phase composition for test mixture separation has been proposed.

Chitin as Stationary Phase in Thin-Layer Chromatography–Application of Chromatographic Process Optimization Theory for Chitin Layers

Abstract This paper describes initial of two basic theories of adsorption thin-layer chromatography potimization namely thermodynamic adsorption theory and theory based on mass action law, so called Snyder s theory in chromatographic systems containing chitin as stationary phase on wchich various amino acids were chromatographed. The results obtained were comparable to those obtained for analogous chromatographic systems containing silica gel as stationary phase. Comparison of applicability of these theories for well investigated silica gel and for not enough investigate chitin will permit to draw introductory conclusions about the processes carrying in the chromatographic systems containing chitin as stationary phase.