Development of new HPLC method for identification of metabolic degradation of N-pyrrolylhydrazide hydrazones with determined MAO- B activity in cellular cultures

In this research, a new rapid PR- HPLC method was developed for the determination of metabolites in isolated rat hapatocytes. The chromatographic parameters, including the stationary and mobile phases, outlet pressure, temperature and flow rate, were optimized. The method identified two initial from the synthesis molecules in higher concentration and one new unidentified structure as products of the hepatocytic processing of the evaluated analyte. The results identified as first step of metabolism the hydrolysis of the hydrazone group. Further investigations should be aimed into determining the next metabolic transformations, predicted by the in silico application of the web server SMARTCyp.

Comparative Chiral Separation of Thalidomide Class of Drugs Using Polysaccharide-Type Stationary Phases with Emphasis on Elution Order and Hysteresis in Polar Organic Mode

The enantioseparation of four phthalimide derivatives (thalidomide, pomalidomide, lenalidomide and apremilast) was investigated on five different polysaccharide-type stationary phases (Chiralpak AD, Chiralpak AS, Lux Amylose-2, Chiralcel OD and Chiralcel OJ-H) using neat methanol (MeOH), ethanol (EtOH), 1-propanol (PROP), 2-propanol (IPA) and acetonitrile (ACN) as polar organic mobile phases and also in combination. Along with the separation capacity of the applied systems, our study also focuses on the elution sequences, the effect of mobile phase mixtures and the hysteresis of retention and selectivity. Although on several cases extremely high resolutions (Rs > 10) were observed for certain compounds, among the tested conditions only Chiralcel OJ-H column with MeOH was successful for baseline-separation of all investigated drugs. Chiral selector- and mobile-phase-dependent reversals of elution order were observed. Reversal of elution order and hysteresis of retention and enantioselectivity were further investigated using different eluent mixtures on Chiralpak AD, Chiralcel OD and Lux Amylose-2 column. In an IPA/MeOH mixture, enantiomer elution-order reversal was observed depending on the eluent composition. Furthermore, in eluent mixtures, enantioselectivity depends on the direction from which the composition of the eluent is approached, regardless of the eluent pair used on amylose-based columns. Using a mixture of polar alcohols not only the selectivities but the enantiomer elution order can also be fine-tuned on Chiralpak AD column, which opens up the possibility of a new type of chiral screening strategy.

Penetapan Kadar Metilparaben dalam Sediaan Krim Wajah yang Beredar di Kabupaten Pekalongan dengan Metode High Performance Liquid Chromatography (HPLC)

Methylparaben is a preservative that is often added in cosmetic preparations. The addition of methylparaben in cosmetics aims to protect the preparation from fungus so that cosmetic preparations are not easily damaged. The side effects of using methylparaben in the long term are irritation, allergic reactions, inflammation, and skin dermatitis. The purpose of this research was to analyze the content of methylparaben and determine the concentrationof metil paraben in the face cream samples. The qualitative test used Thin Layer Chromatography (TLC) method, mobile phases used were chloroform and methanol (9:1). Quantitative test used High Performance Liquid Chromatography (HPLC) method with methanol and aquabides as mobile phases (6:4). The results obtained in TLC are the sample Rf value is not much different from the standard Rf value, the standard Rf value is 0.60. Of the 10 samples analyzed, 8 spots appeared on samples 1, 2, 3, 4, 5, 6, 8, and 10 with an Rf value of 0.58, respectively; 0.57; 0.58; 0.57; 0.57; 0.57; 0.58; and 0.60. In the HPLC analysis, it was obtained that the sample levels in samples 1, 2, 3, 4, 5, 6, 8, and 10 were 0.33%, respectively; 0.30%; 1.21%; 0.29%; 0.52%; 0.44%; 0.41% and 1.14%. Samples 3 and 10 are not safe to use.Keywords: determination; face cream; preservative; methylparaben; HPLC. AbstrakMetilparaben adalah zat pengawet yang sering ditambahkan dalam sediaan kosmetik. Penambahan metilparaben dalam kosmetik bertujuan untuk menjaga sediaan agar terhindar dari jamur sehingga sediaan kosmetik tidak cepat rusak. Efek samping penggunaan metilparaben dalam jangka panjang yaitu dapat menimbulkan iritasi, reaksi alergi, inflamasi, dan dermatitis kulit. Tujuan dari penelitian ini adalah untuk menganalisis kandungan metilparaben dan mengetahui kadar metil paraben dalam sampel krim wajah. Pengujian secara kualitatif menggunakan metode Kromatografi Lapis Tipis (KLT), fase gerak yang digunakan yaitu kloroform dan metanol (9:1). Pengujian secara kuantitatif menggunakan metode High Performance Liquid Chromatography (HPLC) dengan fase gerak metanol dan aquabides (6:4).Hasil yang diperoleh pada KLT yaitu nilai Rf sampel tidak jauh berbeda dengan nilai Rf standar, nilai Rf standar sebesar 0,60. Dari 10 sampel yang dianalisis yaitu muncul 8 bercak pada sampel 1, 2, 3, 4, 5, 6, 8, dan 10 dengan nilai Rf berturut-turut yaitu sebesar 0,58; 0,57; 0,58; 0,57; 0,57; 0,57; 0,58; dan 0,60. Pada analisis HPLC diperoleh kadar sampel yaitu pada sampel 1, 2, 3, 4, 5, 6, 8, dan 10 secara berturut-turut sebesar 0,33%; 0,30%; 1,21%; 0,29%; 0,52%; 0,44%; 0,41% dan 1,14%. Sampel 3 dan 10 tidak aman untuk digunakan.Kata kunci: penetapan; krim wajah; pengawet; metilparaben; HPLC.

Penetapan Kadar β-karoten dalam Buah Tomat (Lycopersicum esculentum Mill.) Berdasarkan Ketinggian Tempat Tumbuhnya dengan Metode Spektrofotometri UV-Vis

The quality of secondary metabolites in plants is determined by the altitude where they grow, in tomato plants secondary metabolites that have the potential as antioxidant activity are caused by β-carotene. β-carotene is a red-orange pigment that is very abundant in plants and fruits. β-carotene is an organic compound and is classified as a terpenoid, β-carotene is also one of the antioxidants that can prevent disease. The purpose of this study was to determine the level of β-carotene in tomatoes based on the altitude where they grew. The sample used in this study was Tomato Fruit (Lycopersicum esculentum Mill.) which was taken at an altitude of ±1206, ±845, ±548 and ±76 masl. Qualitative testing using Fourier Transform Infra Red (FTIR) and Thin Layer Chromatography (TLC), the mobile phases used are chloroform and ethyl acetate (7:3), the Rf values of the samples and comparisons are not much different. Quantitative testing using UV-Vis Spectrophotometry method at a wavelength of 461 nm. The results showed that the four positive samples contained β-carotene. The levels of β-carotene in the samples studied were sample A (±1206 masl) as much as 5.642 mg/100 gr, sample B (±845 masl) as much as 7.986 mg/100 gr, sample C (±548 masl) as much as 11.128 mg/100 gr and sample D (±76 masl) as much as 3.792 mg/100 gr. From this study, it was found that the highest β-carotene content was found in sample C (±548 masl) and the lowest β-carotene level was found in sample D (±76 masl). Environmental factors such as light, temperature, pH, altitude, and temperature greatly affect the content of β-carotene.Keywords: Determination of rates; β-carotene; tomatoes; UV-Vis spectrophotometry AbstrakKualitas metabolit sekunder dalam tumbuhan salah satunya ditentukan oleh ketinggian tempat tumbuhnya, dalam tanaman tomat metabolit sekunder yang berpotensi sebagai aktivitas antioksidan salah satunya disebabkan oleh β-karoten. β-karoten adalah pigmen berwarna merah-orange yang sangat berlimpah pada tanaman dan buah-buahan. β-karoten merupakan senyawa organik dan diklasifikasikan sebagai suatu terpenoid, β-karoten juga merupakan salah satu antioksidan yang dapat mencegah penyakit. Tujuan dari penelitian ini adalah untuk mengetahui kadar β-karoten dalam buah tomat berdasarkan ketinggian tempat tumbuhnya. Sampel yang digunakan dalam penelitian ini adalah Buah Tomat (Lycopersicum esculentum Mill.) yang diambil pada ketinggian ±1206, ±845, ±548 dan ±76 mdpl. Pengujian secara kualitatif menggunakan metode Fourier Transform Infra Red (FTIR) dan Kromatografi Lapis Tipis (KLT), fase gerak yang digunakan yaitu berupa kloroform dan etil asetat (7:3) diperoleh nilai Rf sampel dan pembanding yang tidak jauh berbeda. Pengujian secara kuantitatif menggunakan metode Spektrofotometri UV-Vis pada panjang gelombang 461 nm. Hasil penelitian menunjukkan bahwa dari keempat sampel positif mengandung β-karoten. Kadar β-karoten dalam sampel yang diteliti yaitu sampel A (±1206 mdpl) sebanyak 5,642 mg/100 gr, sampel B (±845 mdpl) sebanyak 7,986 mg/100 gr, sampel C (±548 mdpl) sebanyak 11,128 mg/100 gr dan sampel D (±76 mdpl) sebanyak 3,792 mg/100 gr. Dari penelitian ini diketahui bahwa kadar β-karoten tertinggi terdapat pada sampel C (±548 mdpl) dan kadar β-karoten terendah terdapat pada sampel D (±76 mdpl). Faktor lingkungan seperti cahaya, suhu, pH, ketinggian tempat, dan temperature sangat berpengaruh terhadap kandungan β-karoten.Kata kunci: Penetapan kadar; β-karoten; buah tomat; spektrofotometri UV-Vis

Determination of Levamisole and Mebendazole and Its Two Metabolite Residues in Three Poultry Species by HPLC-MS/MS

A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to simultaneously analyze levamisole (LMS) and mebendazole (MBZ) and its two metabolites, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry muscle (chicken, duck and goose). In the sample preparation process, basic ethyl acetate was used as the extraction agent, and the extracted samples were back-extracted with hydrochloric acid, purified by Oasis MCX solid-phase extraction (SPE) cartridges, and reconstituted in the initial mobile phase after being blown dry with nitrogen. Chromatographic separation was performed on an Xbridge C18 column (4.6 mm × 150 mm, 5 μm) with 0.1% formic acid in water and acetonitrile as the mobile phases, and gradient elution was performed at a flow rate of 0.6 mL/min and a column temperature of 35 °C. In blank poultry muscle samples, the spiked concentrations of LMS, MBZ, HMBZ, and AMBZ were within the range of the limit of quantitation (LOQ) to 25 μg/kg. The peak areas of the four target drugs had a good linear relationship with the concentration, and the determination coefficient (R2) values were higher than 0.9990. The average recoveries of LMS, MBZ, HMBZ, and AMBZ were 86.77–96.94%; the intraday relative standard deviations (RSDs) were 1.75–4.99% at LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL, and 2.0 MRL; the interday RSDs were 2.54–5.52%; and the LODs and LOQs were 0.04–0.30 μg/kg and 0.12–0.80 μg/kg, respectively.

Mathematical Modelling in Analytical Chromatography: Problems and Solutions

Based on an analysis of the results of original research performed in the Laboratory of Sorption Methods of the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences within the project “Mathematical Chromatograph,” the review covers the aim and strategy of the imitation modeling of high-performance chromatography; associated problems of the theory of intermolecular interactions; classifications of polar stationary phases by their selectivity; descriptions of the kinetics and dynamics of sorption processes, choice of the composition of multicomponent mobile phases in HPLC and ion chromatography using the method of the dynamic map of a chromatographic system; and the development of alternating gradient modes using a mathematical experiment.

A Comparative Study of the Lipophilicity of Metformin and Phenformin

The results presented in this paper confirm the beneficial role of an easy-to-use and low-cost thin-layer chromatography (TLC) technique for describing the retention behavior and the experimental lipophilicity parameter of two biguanide derivatives, metformin and phenformin, in both normal-phase (NP) and reversed-phase (RP) TLC systems. The retention parameters (RF, RM) obtained under different chromatographic conditions, i.e., various stationary and mobile phases in the NP-TLC and RP-TLC systems, were used to determine the lipophilicity parameter (RMW) of metformin and phenformin. This study confirms the poor lipophilicity of both metformin and phenformin. It can be stated that the optimization of chromatographic conditions, i.e., the kind of stationary phase and the composition of mobile phase, was needed to obtain the reliable value of the chromatographic lipophilicity parameter (RMW) in this study. The fewer differences in the RMW values of both biguanide derivatives were ensured by the RP-TLC system composed of RP2, RP18, and RP18W plates and the mixture composed of methanol, propan-1-ol, and acetonitrile as an organic modifier compared to the NP-TLC analysis. The new calculation procedures for logP of drugs based on topological indices 0χν, 0χ, 1χν, M, and Mν may be a certain alternative to other algorithms as well as the TLC procedure performed under optimized chromatographic conditions. The knowledge of different lipophilicity parameters of the studied biguanides can be useful in the future design of novel and more therapeutically effective metformin and phenformin formulations for antidiabetic and possible anticancer treatment. Moreover, the topological indices presented in this work may be further used in the QSAR study of the examined biguanides.