Synthesis of Ester-Linked Paclitaxel-Glycoside Conjugate as a Water-Soluble Paclitaxel Derivative—Maltoside Modification of Paclitaxel through Ester-Linker (Ester-Spacer)

To synthesize a water-soluble paclitaxel derivative, the anomers of diols of allyl 2,3,4-tri- O-benzyl-6- O-tritylglycoside (maltoside) were prepared, which can be separated by chromatographic procedure. One anomer was converted into α-glycosyloxyacetic acid (maltosyloxyacetic acid) by oxidative cleavage of the diol and subsequent oxidation. Ester-linked paclitaxel-glycoside conjugate, 7-glycolylpaclitaxel 2″- O-α-maltoside, was provided by condensation of 2′-TES paclitaxel with α-glycosyloxyacetic acid (maltosyloxyacetic acid) followed by deprotection of hydroxy groups.

A novel comparative chromatographic research of secoiridoid glycosides in two species of centaury herb

The aim: A novel comparative analysis of the secoiridoid glycosides composition in Centaurium erythraea Rafn. and Cеntaurium pulchellum (Sw.) Druce has being described. Swertiamarin has been chosen as an active marker and its comparative quantitative estimation in two species of the raw material has been carried out by HPLC method. Materials and methods: The quantitative HPLC analysis of swertiamarin was conducted using a chromatographic column ACE 5 C18. Methanol and 0,5 % acetic acid aqueous solution were used as mobile phases; the chromatographic procedure was carried out in a gradient mode. Results: The content of swertiamarin in the C. pulchellum herb ranges from 2.51 to 3.07 mg/100 mg. In that time swertiamarin content in C. erythraea herb varies and depends from 3.83 to 8.94 mg/100 mg. The content of swertiamarin in C. pulchellum herb is much lower than in C. erythraea herb. Taking into account this fact the possibility of using of C. pulchellum herb for medicine instead of C. erythraea herb must be proven additionally by biological experiments. Also it could be preliminary concluded that the most appropriate climate for swertiamarin accumulation in C. erythraea herb is located in Central and Eastern parts of Ukraine. Conclusions: It was discovered that the main representative of secoiridoid glycosides in C. erythraea is swertiamarin when in C. pulchellum Druce that are represented by both sweroside and swertiamarin. A more perspective raw material – C. erythraea herb, according to the content of swertiamarin, was chosen

Application of Micellar Mobile Phase for Quantification of Sulfonamides in Medicated Feeds by HPLC-DAD

Rapid chromatographic procedure for quantification of five sulfonamides in medicated feeds are proposed. Satisfactory separation of sulfonamides from medicated feeds was achieved using a Zorbax Eclipse XDB C18 column (4.6 × 150 mm, 5 µm particle size) with a micellar mobile phase consisting of 0.05 M sodium dodecyl sulphate, 0.02 M phosphate buffer, and 6% propan-2-ol (pH 3). UV quantitation was set at 260 nm. The proposed procedure allows the determination of sulfaguanidine, sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole in medicated feeds for pigs and poultry. Application of the proposed method to the analysis of five pharmaceuticals gave recoveries between 72.7% to 94.7% and coefficients of variations for repeatability and reproducibility between 2.9% to 9.8% respectively, in the range of 200 to 2000 mg/kg sulfonamides in feeds. Limit of detection and limit of quantification were 32.7–56.3 and 54.8–98.4 mg/kg, respectively, depending on the analyte. The proposed procedure for the quantification of sulfonamides is simple, rapid, sensitive, free from interferences and suitable for the routine control of feeds. In the world literature, we did not find the described method of quantitative determination of sulfonamides in medicated feeds with the use of micellar liquid chromatography.

A Rapid HPLC Method for the Concurrent Determination of Several Antihypertensive Drugs from Binary and Ternary Formulations

A rapid, synchronized liquid chromatographic method was established for the estimation of hydrochlorothiazide (HCZ), amlodipine (AMD), olmesartan (OLM), telmisartan (TEL), and irbesartan (IRB) in binary and ternary coformulations using the same chromatographic conditions. Five analytes were separated on a Zorbax C18 column using isocratic elution with a mobile phase consisting of acetonitrile, methanol, and 20 mM phosphate buffer (pH 3.5) in a ratio of 45:20:35% v/v. The analytes were detected at a wavelength of 230 nm at ambient temperature. Furthermore, the proposed liquid chromatographic procedure was validated for linearity, precision, accuracy, stability, and robustness using an experimental design. Analytes were separated with good resolution within 3.5 min. Analytes showed good linearity in a concentration satisfactory to analyze the different ratios of these analytes in the formulations. Pareto charts showed that the flow rate and mobile phase composition have a significant effect on the peak area of analytes and hence need to be carefully controlled, however, the method is robust. Finally, the different formulations consisting of HCZ, AMD, OLM, TEL, and IRB in different ratios were analyzed with high accuracy using an optimized HPLC method and compared with reported methods. Furthermore, the reported HPLC procedure is simple, rapid, and accurate and therefore can used for regular quality control of binary and ternary formulations using the same stationary and mobile phase.

Analytical Method Development and Validation for Simultaneous estimation of Methotrexate and Hydroxychloroquine sulfate in bulk drug by using RP-HPLC

A rapid isocratic chromatographic procedure for the analysis of methotrexate, hydroxychloroquine sulfate in bulk drug and pharmaceutical formulations was developed validated in the present study. The mobile phase consists of a mixture of Water: Acetonitrile: Tetrahydrofuran in the proportion of 50:40:10 and pH maintained to 3with perchloric acid. Retention time was found to be 3.0 and 3.7minutes for methotrexate and hydroxychloroquine sulfate respectively. The method was performing by using the C18 column, ODS Hypersil column with UV detection at 318nm, and flow rate of 1.0ml/min. The percentage of recovery for both drugs was found to be 99.99%. All validation parameters were within limits as per the ICH guidelines.

Improved ion-exchange column chromatography for Cu purification from high-Na matrices and isotopic analysis by MC-ICPMS

Measurements of Cu isotopes from low concentration and high salinity matrices require high recovery and purity prior to measurement. A new automated two-stage chromatographic procedure yields highly pure Cu separations, low procedure blanks and much-improved reproducibility.

Electrodeposition of 4-Benzenesulfonic Acid onto a Graphite-Epoxy Composite Electrode for the Enhanced Voltammetric Determination of Caffeine in Beverages

Caffeine is widely present in food and drinks, such as teas and coffees, being also part of some currently commercialized medicines, but despite its enhancement on several functions of human body, its exceeding use can promote many health problems. In order to develop new fast approaches for the caffeine sensing, graphite-epoxy composite electrodes (GECE) were used as substrate, being modified by different diazonium salts, synthetized as their tetraflouroborate salts. An analytical method for caffeine quantification was developed, using sware wave voltammetry (SWV) in Britton–Robinson buffer pH 2.0. Detection limits for bare electrode and 4-benzenesulfonic modified electrode were observed circa 145 µmol·L−1 and 1.3 µmol·L−1, respectively. The results have shown that the modification shifts the oxidation peaks to lower potential. Kinetics of the reaction limited by diffusion was more expressive when caffeine was added to the solution, resulting in decreases of impedance, characterized by lower Rct. All results for caffeine determination were compared to a reference chromatographic procedure (HPLC), showing no statistical difference. Analytical parameters for validation were suitably determined according to local legislation, leading to a linear behaviour from 5 to 150 µmol·L−1; precision of 4.09% was evaluated based on the RDC 166/17, and accuracy was evaluated in comparison with the reference method, with recovery of 98.37 ± 2.58%.