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The influence of different chromatographic conditions and the process of spot visualization on determining the limit of detection as well as quantification (LOD and LOQ) of meloxicam by TLC-densitometric technique was estimated. Of all chromatographic conditions tested, the lowest limiting values, thus the best sensitivity, in the NP-TLC system was achieved on silica gel 60F254 and neutral aluminum oxide plates developed with the mobile phase consisting of ethyl acetate/toluene/n-butylamine (2:2:1, V/V/V). In the case of the RP-TLC method, a mixture of methanol/water (8:2, V/V) enabled densitometric detection of meloxicam at the lowest concentration level on RP-8F254 and RP-18F254 plates. Additionally, the smallest LOD value of meloxicam ensured crystalline violet and gentian violet as visualization agents on silica gel 60F254 and neutral aluminum oxide 150F254 plates, resp. Comparison of the densitometrically obtained spectra of meloxicam drug and its standard after the use of appropriate visualization agents could be a good and cheap alternative tool for the identification of meloxicam as an active pharmaceutical ingredient.

Subject of study Coffee infusions are extremely popular worldwide due to their pleasant taste, ability to reduce fatigue, increase concentration and improve productivity. Infusion extracted from coffee beans are mixtures of many chemical compounds, both volatile and non-volatile. Among the non-volatile components, caffeine, trigonelline and chlorogenic acid appear to be the dominant ones. These substances are responsible for both the flavour sensations and influence on biological activities, such as mental stimulation effects or reducing the risk of type 2 diabetes. Aim of study The aim of the present study was: (I) to develop and validate a high-performance thin-layer chromatography (HPTLC) method for the simultaneous quantification of caffeine, trigonelline and chlorogenic acid in coffee bean infusions; (II) to use this method to determine caffeine, trigonelline and chlorogenic acid in green, light and dark roasted coffee bean infusions prepared both by immersion (brewing) and pressure methods; (III) to evaluate the effects of coffee infusions on α-amylase activity. Materials and methods Simultaneous determination of caffeine, trigonelline and chlorogenic acid was carried out on glass HPTLC plates coated with silica gel 60 F254 with a concentration zone and the mobile phase consisted of a mixture of: chloroform, ethyl acetate, methanol and formic acid in a volume ratio of 10:6:3:1 (v/v). After the plates were developed and dried, densitometric scanning was performed at wavelengths of 270, 275 and 330 nm for trigonelline, caffeine and chlorogenic acid, respectively. The analysis of the effect of coffee infusions on the α-amylase activity was carried out using a porcine pancreas α-amylase. Results Green coffee infusions prepared using the immersion method was proved to have the highest chlorogenic acid content, while the highest trigonelline and caffeine contents were observed in infusions also obtained using the immersion method, but from dark-roasted coffee. Infusions of green coffee and light and dark roasted coffee inhibited α-amylase activity, with green coffee infusions showed the strongest effect. Conclusions The developed method is selective, precise, accurate and sensitive, so it can be used for the simultaneous determination of caffeine, trigonelline and chlorogenic acid in heat-treated and non-heat-treated coffee bean infusions. The results of the analysis of the effect of coffee infusions on the α-amylase activity create the opportunity to use these infusions, particulary unroasted coffee infusions, in the prevention of type 2 diabetes.

A new TLC–densitometric method has been developed for the identification and quantification of paracetamol (PA), propyphenazone (PP) and caffeine (C) in Saridon tablets using the NP-TLC technique combined with densitometry. This method allows for the simultaneous determination of PA, PP, and C in the same sample. Among all the tested chromatographic conditions, the mixture consisting of chloroform + toluene + ethyl acetate + ethanol + acetic acid (18:18:7.5:5.0:0.3, v/v/v/v/v) and a silica gel 60F254 plate proved to be the most effective for the separation of the three tested active pharmaceutical ingredients (APIs) and substances related to paracetamol. The full validation of the proposed NP-TLC method proved that it is specific, precise, accurate, robust and sensitive. The percentage content in relation to the content declared by the manufacturer was for propyphenazone 99.8%, paracetamol 101.6% and caffeine 100.8%, which was in accordance with pharmacopoeial requirements. The results presented indicate the possibility of using the developed method in the routine control of pharmaceutical preparations containing these APIs. The proposed method is economical and more sensitive compared to the previously proposed planar methods for the simultaneous determination of APIs. What is more, the presented method may be an excellent economical alternative when the HPLC method is unavailable for such a determination.

Caffeine (1,3,7-trimethylxanthine) is a psychostimulant that acts as an adenosine receptor antagonist. It is a naturally occurring central nervous system (CNS) stimulant of the methylxanthine class that can be isolated from more than sixty plants, but can also be produced synthetically and added to our daily foods and medicines. Depending on the plant in which it occurs, it is referred to by a different name, such as guaranine (when it comes from guarana seeds), matein (when it comes from yerba mate), and theine (when it comes from tea leaves). It is considered the most often used psychoactive drug in the world. It is used in the preparation of daily beverages to refresh and offset symptoms of mental and physical fatigue, which are commonly used around the world in the form of coffee, tea or chocolate. There are also many medications containing caffeine, and the substance is also added to carbonated drinks (Pepsi, Coca-Cola) and energy drinks. After oral administration, caffeine is quickly and completely (i.e.99%) absorbed from the gastrointestinal tract. After absorption from the gastrointestinal tract ( especially the small intestine), caffeine is distributed throughout the body. It penetrates all tissues through cell membranes and enters the water space of tissues. Caffeine is practically completely biotransformed in the liver, only 2% of the ingested dose is excreted unchanged in the urine. Caffeine metabolism is affected by many exogenous and endogenous factors, such as genetics, age, gender, pregnancy, diet, lifestyle, smoking, environmental factors, drugs and diseases. Caffeine is removed from the body mainly by the kidneys. The FDA ( Food and Drug Administration) has approved caffeine for use in the treatment of apnea and the prevention and treatment of bronchopulmonary dysplasia in premature infants. Caffeine modifies the effects of some medications. Caffeine has a wide range of effects on the body, both positive and negative, that may partially affect the variability of caffeine consumption between individuals.

TLC (thin-layer chromatography) and HPTLC (high-performance thin-layer chromatography) in normal (NP) and reversed (RP) phase systems were combined with densitometry to analyze caffeine, propyphenazone, and paracetamol. This work aims to check whether comparable limit of detection (LOD) values can be obtained on TLC and HPTLC plates. Analyses were performed on five (NP) or four (RP) different stationary phases (chromatographic plates), testing, in both cases, three mobile phases. It is shown that by using both TLC and HPTLC plates, it is possible to develop chromatographic conditions that enable the detection of compounds analyzed in amounts ranging from a dozen to several dozen µg/spot. In the RP system, lower LOD values for all tested compounds were obtained using TLC than HPTLC. However, performing analyses in the NP, similar (of the same order) LOD values were obtained for caffeine, propyphenazone, and paracetamol when using both TLC and HPTLC plates. For example, during the NP-HPTLC analysis using silica gel 60F254 plates (#1.05548) and mobile phase B (n-hexane—acetone—ammonia, 25:25:0.5, v/v/v), LOD values for caffeine, propyphenazone, and paracetamol were 0.010, 0.046, and 0.030 μg/spot, respectively. During NP-TLC analysis using silica gel 60F254 (#1.05554 plates) and the mobile phase C (chloroform—toluene—ethyl acetate—methanol—80% acetic acid, 18:18:7.5:6:0.3, v/v), the values of LOD were 0.054, 0.029, and 0.016 μg/spot, respectively. During RP-TLC analysis using TLC RP-18F254 plates (#1.05559) and mobile phase F (methanol-water, 40:10, v/v), the LOD values were 0.019, 0.024, and 0.053 μg/spot, respectively. Therefore, for economical reasons, TLC plates should be recommended for analyses of caffeine, propyphenazone, and paracetamol, which are several times cheaper than HPTLC plates. [ABSTRACT FROM AUTHOR]

TLC combined with densitometry was used and chromatographic conditions developed to separate omeprazole and diclofenac sodium from their potential impurities. The development of the TLC–densitometry method is based on the elaboration of new chromatographic conditions allowing for the simultaneous determination of omeprazole and diclofenac sodium in a pharmaceutical preparation. Identification and quantification of omeprazole in simple and combined (with diclofenac) pharmaceutical preparations was performed on silica gel 60F254 using one mobile phase: chloroform–methanol–ammonia (36:4:0.60, v/v). Diclofenac sodium was determined in the presence of omeprazole after 2D separation on silica gel using two mobile phases of the first phase of chloroform–methanol–ammonia (36:4:0.60, v/v) and the second mobile phase cyclohexane–chloroform–methanol–glacial acetic acid (6:3:0.5:0.5 v/v). The developed method is simple, economical, specific, precise, accurate, sensitive, and robust, with a good range of linearity for the quantification of omeprazole and diclofenac sodium. TLC in combination with densitometry can be used as an effective analytical tool for quality control and quantitative determination of omeprazole in simple and combined pharmaceutical preparations containing diclofenac sodium. TLC in combination with densitometry can be recommended for the analysis of omeprazole and diclofenac sodium in the absence of HPLC or spectrophotometer in the laboratory or to confirm results obtained with other analytical techniques.

The aim of this study was to assess the lipophilicity of selected antiparasitic, antihypertensive and non-steroidal anti-inflammatory drugs (NSAIDs) by means of reversed phase−thin layer chromatography (RP-TLC) as well by using Soczewiński−Wachtmeister’s and J. Ościk’s equations. The lipophilicity parameters of all examined compounds obtained under various chromatographic systems (i.e., methanol-water and acetone-water, respectively) and those determined on the basis of Soczewiński-Wachtmeister’s and Ościk’s equations (i.e., RMWS and RMWO) were compared with the theoretical ones (e.g., AlogPs, AClogP, milogP, AlogP, MlogP, XlogP2, XlogP3) and the experimental value of the partition coefficient (logPexp). It was found that the RMWS parameter may be a good alternative tool in describing the lipophilic nature of biologically active compounds with a high and low lipophilicity (i.e., antihypertensive and antiparasitic drugs). Meanwhile, the RMWO was more suitable for compounds with a medium lipophilicity (i.e., non-steroidal anti-inflammatory drugs). The chromatographic parameter φ0(a) can be helpful for the prediction of partition coefficients, i.e., AClogP, XlogP3, as well as logPexp of examined compounds.

This study reports the development and validation of a new, simple, and accurate high-performance thin-layer chromatography (HPTLC)-densitomeric method for the determination of nandrolone decanoate in a commercially available injection formulation. Chromatographic analysis was performed on glass CN modified silica gel 60F254 plates developed using n-hexane-ethyl acetate in volume ratio 42.5:7.5 as the mobile phase. Densitometric scanning was carried out at the wavelength of 245 nm. This chromatographic system gave compact spot and a symmetrical peak of nandrolone decanoate with retardation factor (RF) value at 0.57 (±0.02). The linearity of this method with the high correlation coefficient of calibration plot ranges from 0.780 to 12.500 μg/spot. The developed method is characterized by good precision (coefficient of variation CV < 2%) and high accuracy close to 100.3% (R = 99.0%). Values of limits of detection and quantification equal to 0.231 and 0.700 μg/spot, respectively, confirm the sensitivity of the developed method. The analysis of the pharmaceutical formulation of nandrolone decanoate indicates drug content of 50.5 mg/mL and 101.0% in relation to the label claim. This is in good agreement with the recommendation of the International Council for Harmonisation (ICH) guidelines as well as the pharmacopoeial requirements. The low CV value (

Effect of cyclosporin A (CsA) in a therapeutic concentration, on the expression of cytochrome P450 genes (CYPs), was investigated in normal human dermal fibroblast cells. The expression of 57 genes, encoding cytochrome P450 isoforms, was estimated using the microarray method. Amongst 396 normalized fluorescence signals related to cytochrome P450 activity, only 91 were strictly connected to CYPs and were analyzed using two methods: a self-organizing feature map of artificial neural networks and typical statistical analysis with significance level at p ≤ 0.05. Comparing the samples from fibroblasts cultured with CsA and those cultured without, up-regulated changes of CYP19A1, 1B1, 7A1, 7F1, 17A1 and down-regulated 2D6 gene expression were observed. The mRNAs with increased changes were in the same neuron of the self-organizing feature map. All distinguished CYPs encode monooxygenases, which plays an important role in steroids biosynthesis and metabolism. Based on the obtained results, we can conclude that CsA in therapeutic concentration changes the expression profile of CYPs in human dermal fibroblasts, especially affecting genes linked to steroids synthesis and/or metabolism. It shows the potential mechanism of action of CsA in human dermal fibroblast cells.

Valproic acid and its derivatives are drugs that have been used in many neurogenic diseases, but are mainly used in epileptic seizures. Due to the fact that valproic acid doesn’t have conjugated double bonds, it isn’t visible under UV light and its detection is difficult. Therefore, the aim of the study was to assess the suitability of individual visualizing reagents in the chemical qualitative and quantitative detection of valproic acid using the TLC technique. Solutions of various visualizing reagents were prepared, and then the reagents were applied to the previously prepared chromatographic plates with valproic acid by means of an immersion and spraying method in order to detect it. It was shown that all the visualizing reagents used, with the exception of helasol green, bromothymol blue, malachite green, bromocresol green in 2% sodium hydroxide solution and sulfate (VI) solutions of iron (II), nickel, and cobalt, allowed for the qualitative detection of valproic acid. It is recommended to use a 1% solution of copper (II) sulfate (VI) for the detection of valproic acid for both qualitative and quantitative purposes, due to the largest areas of the chromatographic bands on most of the chromatographic plates used in the study. There is a potential possibility of examining the identity of valproic acid present in drugs on the basis of the RF value, the characteristic color of the spot, and a comparative analysis of spectrodensitograms. [ABSTRACT FROM AUTHOR]