Chromatographia最新文献

Indacaterol, glycopyrronium, and mometasone furoate triple combination inhalable fixed-dose medicines are effectively used to treat asthma and various chronic pulmonary disorders. The study aimed to develop and validate a simple single-run RP-HPLC impurity quantitation method. The chromatographic separation was accomplished using gradient elution mode of mobile phase A (potassium dihydrogen phosphate buffer pH 2.2) and mobile phase B (mixture of acetonitrile and methanol), with a flow rate of 0.8 mL/min using YMC Triart, C₁₈ (250 × 4.6 mm, 5 µm) HPLC column at 45 °C and the detection wavelength of 210 nm (for indacaterol, glycopyrronium and their impurities) and 248 nm (for mometasone furoate and its impurities). Water and methanol (20:80) were used as a diluent. Quantitation of 10 known and several unknown impurities was successfully performed with the determination of relative response factors for all the known impurities. The developed method was validated as per the ICH Q2(R1) guidelines. The stability indicating the nature of the method was proved by performing stress study on the sample and placebo. The linearity and range of the method were proved by calculating the r² values (> 0.998). The overall precision was found to be within 1.82 − 7.76% RSD. The recovery for all the actives and known impurities were within 90 − 115% with 0.4 − 12% RSD. The sample solution was stable for 2 days at room temperature. The developed method can be successfully used for the impurity analysis of routine, stability, and commercial samples in a quality control laboratory of the pharmaceutical industry.

A sensitive and stable spray for thin layer chromatography of acyl-CoA and other thio-compounds has been evaluated. CoA, down to 1 nmol, is readily revealed and by pre- or post-treatment with hydroxylamine or tris(2-carboxyethyl)phosphine, thioesters or disulfides respectively can be stained as well.

A virus is a sub-microscopic infectious organism that causes diseases in humans, animals, and plants resulting in morbidity and may cause mortality. Proper diagnosis is necessary to initiate the treatment and pave the way to eradicate the viral infection. The current diagnostic kits for nucleic acid amplification assay, blood filtration, single-cell analysis are highly accurate, even though the procedure necessitates large sample volumes, complicated fabrication steps, time-consuming processes, and high costs. The filtration of viral samples from the blood is a tedious process. In this research, we have presented a home-based fabricated paper microfluidic chip to effectively filtrate viral particles from the sample to facilitate the nucleic acid amplification assay. The filtration analysis was exhibited for lateral and vertical flow paper chips fabricated via laser printing and polyethylene terephthalate (PET) encapsulation that circumvents the necessity of a traditional wax printer and hot plate. The results convey that the vertical flow paper chip with grade 4 inlet and outlet filters 98.57% of unnecessary particles from the sample. The paper-based microfluidic chip developed in this research is simple, easy to fabricate, and inexpensive to access in underdeveloped countries. The paper chip can pave the way for applications like lab-on-chip devices, POC assays, rapid nucleic acid amplification tests, cell cultures, and biomolecular research.

Vitamin B2 and vitamin B6 are cofactors and coenzymes in many biochemical reactions, and their sufficient serum concentrations may be crucial for the proper functioning of the thyroid gland. The aim of the study was to develop and validate a novel high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the determination of vitamin B2 and vitamin B6 in the serum of patients with Hashimoto’s thyroiditis (HT). Detection of the analytes was performed on a triple-quadrupole MS with multiple reaction monitoring using electrospray ionization. The mobile phase consisted of water and methanol, both containing 0.1% (v/v) formic acid. The analytes were isolated from serum by the one-step sample preparation of the trichloroacetic acid precipitation. Validation parameters, including linearity, accuracy, precision, limits of detection and quantification, and stability, were determined and fulfilled the criteria for analyzing compounds in biological fluids. The method was applied for the determination of the above vitamin concentrations in serum samples of 74 patients with HT and 33 healthy controls. The concentration of vitamin B2 was significantly lower in patients with HT compared to the control group (7.20 ± 7.86 ng/mL vs. 12.03 ± 9.62 ng/mL) and the concentration of vitamin B6 was also lower, but without a statistically significant difference (30.09 ± 19.16 ng/mL vs. 37.29 ± 23.02 ng/mL). We concluded that the vitamins concentration measurement may be helpful in the diagnosis of vitamin deficiencies and the supplementation strategy.

To analyze 1-methyladenosine (m1A) and 1-methylinosine (m1I) in urine samples obtained from patients with breast cancer and healthy people, we used magnetic dispersive solid-phase micro-extraction (MDSPME) combined with high-performance liquid chromatography. The structure and morphology of magnetic nanoparticles, Fe₃O₄@GO, were investigated by FT-IR, XRD, TEM, and TGA. m1A and m1I in urine samples were enriched by the solid phase micro-extraction technology of Fe₃O₄@GO. Several parameters affecting the extraction efficiency, including adsorption time, pH, ionic strength, mass of adsorbent, extraction time, eluent solvent, elution time, and elution temperature, were researched and optimized. Under the optimized conditions, the corresponding linearity range of the two analytes showed a good linearity (r² > 0.9998) and significant addition recoveries ranging from 88.50 to 109.38%, while the limit of detection was between 0.10 and 0.11 ng/mL. The enrichment factors of m1A and m1I were 108 and 134, respectively. The method was simple, sensitive, and reliable for the detection and purification with good detection limit, and it was suitable for the detection of m1A and m1I in urine samples. In addition, the analysis of modified nucleosides is of great value for the early diagnosis of patients with breast cancer.

Five cyclopentadienone sesquiterpene lactones: austricin, 5β(H)-austricin, achillin, grossmisin and leucomisin were obtained from the plant Artemisia leucodes Schrenk. The lactone purification procedure starting from the plant leaves is described. A quality control method was developed using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). For these stereoisomeric cyclopentadienone guaianolides, the TLC and HPLC relationships “molecular structure—retention time” on the nature of the substituent in the molecular structure were studied. The chromatographic conditions were optimized and the influence of the structure of the molecule on their retention time was discussed comparing retention in both TLC and HPLC methods. The relationship between the structure of a particular cyclopentadienone guaianolide and its chromatographic retention time characterizes the sorption mechanism with the apolar stationary phase. It gives information on the compound polarity and hydrophobicity, information most relevant for these biologically active sesquiterpene γ-lactones, which are possible potent active ingredients of drugs.

A novel flameless operating mode is introduced, which improves the response of a multiple flame photometric detector (mFPD). The mFPD normally has analyte travel through 4 ‘worker’ flames in series before entering a final ‘analytical’ flame where its emission is monitored. Here, it is found that when the analytical flame is not ignited, background luminescence is reduced over 30 times and the strong analyte chemiluminescence of the worker flames can be made to extend a large distance (~ 10 flame widths) into the analytical flame region where it is detected. This occurs for phosphorous (HPO*), quadratic sulfur (S₂*), and linear sulfur (HSO*) emission. Conversely, carbon emission resides inside the worker flames and yields a small negative signal. As a result, very good selectivity over carbon is observed, and improved minimum detectable limits (MDL) of 4 pg S/s (S₂*) and 0.3 pg P/s (HPO*) are obtained, which are up to 20 times lower than previous values reported for the mFPD. Further, linear sulfur (HSO*) yields an MDL of 6 pg S/s, which is over 3 times lower than values reported for other FPDs. Due to the worker flames present in this mode, other benefits of regular mFPD operation are maintained, like uniform analyte response and large quenching resistance. In application, a trace benzothiophene analyte is readily detected within a concentrated diesel fuel matrix in the flameless mFPD mode, while no response is observed in the conventional FPD mode. Results indicate that this flameless operating mode is advantageous for sulfur and phosphorous analysis.

Graphical Abstract

Losartan is an anti-hypertensive drug that belongs to the class of angiotensin-II receptor blockers that act by inhibiting the binding of angiotensin II to its receptor. Aprepitant belongs to the class of neurokinin receptor-1 receptor blockers used to treat nausea and vomiting. In the case of severe hypertension, there are the majority of predominant symptoms occurring but one such symptom is nausea and vomiting. This condition may potentially be treated by a combination of losartan and aprepitant, but there is no information about the pharmacokinetic interactions for this combination. When losartan and aprepitant are taken concomitantly there may be a chance that these two drugs may alter the pharmacokinetics of each other. Thus, the effects of both the drugs were assessed on each other. To assess the preclinical pharmacokinetic drug–drug interaction a rapid, simple, and sensitive approach for the simultaneous estimation of losartan and aprepitant in rat plasma by LC–QqQ-MS/MS has been developed and validated. The separation was done on Agilent ZORBAX Eclipse Plus C18 (4.6 mm × 100 mm, 3.5 µm) by gradient elution using 0.1% (v/v) formic acid in water and acetonitrile. Multiple reaction monitoring was performed using a positive ionization mode. The precursor and product ions for losartan, aprepitant, and telmisartan (internal standard) were m/z 423.2 → 207.0, m/z 535.2 → 277.0, and, m/z 515.3 → 276.1, respectively. The proposed method was validated in accordance with USFDA bioanalytical guidelines. The method was found linear, accurate and sensitive to estimate the losartan and aprepitant in rat plasma with the lowest limit of quantification of 1 ng/mL. The pharmacokinetic parameters like half-life, T_max and the area under the curve for aprepitant have been significantly affected when administered with losartan and vice versa. These results provide insights for futuristic investigation at the pharmacodynamic level of drug–drug interactions for this combination.

A novel technique utilizing metal–organic frameworks (MOFs), namely MIL-53(Al) and ZIF-8, has been developed for the extraction of testosterone from human plasma through dispersive micro-solid phase extraction (D-µ-SPE or DMSPE). The synthesized MOFs were subjected to characterization via Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The parameters affecting the extraction were optimized by response surface methodology (RSM). The optimal extraction conditions were determined to be 15 min for contact time, 1 mg for MIL-53(Al) amount, and 0.23% (w/v) for NaCl concentration. For ZIF-8, a contact time of 22 min, a sorbent amount of 5.4 mg, and a salt concentration of 0.34% (w/v) were obtained. Batch absorption studies were conducted to find appropriate kinetic and isotherm models. The results indicated that while testosterone absorption was favorable in both cases, MIL-53 (Al) had a higher absorption capacity than ZIF-8. Finally, the proposed method was subjected to analytical validation for determination of testosterone in plasma samples. Good analytical performance was achieved, including a dynamic range of 0.05–1 µg/mL using each of the sorbents. The precision (expressed as the relative standard deviation (RSD)) and accuracy (expressed as the percentage error) of the method for testosterone and MIL-53(Al) were found to be 3.40% and 2.79%, respectively, while for testosterone and ZIF-8, they were 4.24% and 4.22%, respectively. The method effectively extracted 97% and 96% of testosterone from spiked plasma samples using MIL-53(Al) and ZIF-8, respectively.

This study aims to develop a chromatographic analytical method, for separation, identification and quantification of degradation products, in veterinary finished product with two active substances enrofloxacin and bromhexine hydrochloride. Analytical method used an Agilent Eclipse Plus C18 column (150 × 4.6 mm, 5 µm particle size) and a mobile phase A consisted of 2.5% (v/v) phosphoric acid adjusted to pH 2.3 with triethylamine and mobile phase B was acetonitrile. Elution was in a gradient mode with total chromatographic time being 21 min. Detection was performed at 248 nm for bromhexine hydrochloride and at 272 nm for enrofloxacin. The method was developed to assure the separation of impurities of enrofloxacin and bromhexine hydrochloride. Specificity in relation with degradation products revealed up to 20 impurities for enrofloxacin and 7 impurities related with bromhexine hydrochloride. The spectra of impurities were chosen among the compounds found in forced degradation studies. Method validation was performed according to VICH GL 2—validation of analytical procedures and included selectivity/specificity, linearity, accuracy, precision, limit of quantification, limit of detection, robustness, and system suitability. Linearity was between 0.015 and 0.06 mg/mL for enrofloxacin and 0.001125–0.005625 mg/mL for bromhexine hydrochloride. Limit of quantification was 0.00292 mg/mL for enrofloxacin and 0.001103 mg/mL for bromhexine hydrochloride. These limits assured method performance, because they are under the reporting threshold of 0.3% as stated in VICH GL11 Impurities in new veterinary medicinal products which is 0.30%. Recovery was calculated on three concentrations for every compound and was 102.99% for enrofloxacin and 102.91% for bromhexine hydrochloride. In terms of intermediate precision, a relative maximum deviation of 2.50% was obtained for area and retention time using two analysts in two different days of application.