Authors:Lénárd Farczádi, Álmos Dósa, Orsolya Melles, and Laurian Vlase
Triclabendazole is one of the main drugs used to treat liver fluke in livestock. A rapid LC-MS/MS method was developed and validated to determine ovine plasma levels of triclabendazole sulfoxide.
A Gemini NX-C18 column was used to achieve analytical separation, with gradient elution of a mobile phase composed of 0.1% formic acid in acetonitril and 0.1% formic acid in water at flow rate of 0.6 mL/min. MRM with positive ESI ionization was used for the detection of triclabendazole sulfoxide (m/z 360.10 from m/z 376.97). Fenbendazole was used as internal standard. Plasma protein precipitation with acetonitrile was used for sample processing.
The method was validated with regards to selectivity, linearity (r > 0.9939), within run and between run precision (CV < 8.9%) and accuracy (bias < 8.9%) over the concentration range 1–100 µg/mL plasma.
The method developed is simple, selective and can be applied in bioequivalence and bioavailability studies.
A simple, rapid, efficient and reproducible method based on High Performance Liquid Chromatography (HPLC) for simultaneous determination of prodrug of voriconazole (POV) and voriconazole in beagle plasma has been established and validated. Omeprazole was utilized as the sole internal standard. Analytes and internal standards were extracted through protein precipitation and separated on a Venusil XBP C18 chromatography column (4.6 × 250 mm, 5 µm). The mobile phase was methanol and 20 mmol/L potassium dihydrogen phosphate. Chromatographic separation was achieved by using an isocratic elution procedure that used 65% methanol and a flow rate of 1 mL/min. The ultraviolet (UV) detection wavelength was 256 nm and the total running time was 15 min. This method showed good linear ranges of 100–75,000 ng/mL for voriconazole prodrug and 200–100,000 ng/mL for voriconazole respectively. The precision and accuracy were acceptable. Analytes in plasma samples are stable under different temperatures and storage conditions. The developed HPLC method has been successfully applied to the studies of toxicokinetics of POV after intravenous drip in beagle and provided important information for the further development and application.
Authors:Vladimir Dobričić, Jelena Bošković, Dragana Vukadinović, Sote Vladimirov, and Olivera Čudina
Eight 17β-carboxamide glucocorticoids with local anti-inflammatory activity were selected and their retention behavior tested in six RP-HPLC systems (I–VI). logkw, a, and φ0 parameters were calculated and correlation with previously determined logPo/w values was examined. RP-HPLC system IV, which consisted of cyano column and methanol–water mobile phases (50:50, 60:40, 70:30, and 80:20, v/v), was selected as the most reliable for lipophilicity prediction and used for the analysis of chromatographic behavior of remaining fourteen 17β-carboxamide glucocorticoids. Quantitative structure-retention relationships analysis was performed and PLS(logkw) model was selected as the most statistically significant. On the basis of selected model and interpretation of corresponding descriptors, new derivatives with higher logkw values and higher expected lipophilicity were designed.
Authors:Tsedekech Gebremeskel Weldmichael, Erika Michéli, and Barbara Simon
Land use change may modify key soil attributes, influencing the capacity of soil to maintain ecological functions. Understanding the effects of land use types (LUTs) on soil properties is, therefore, crucial for the sustainable utilization of soil resources. This study aims to investigate the impact of LUT on primary soil properties. Composite soil samples from eight sampling points per LUT (forest, grassland, and arable land) were taken from the top 25 cm of the soil in October 2019. The following soil physicochemical parameters were investigated according to standard protocols: soil organic matter (SOM), pH, soil moisture, NH4+–N, NO3––N, AL-K2O, AL-P2O5, CaCO3, E4/E6, cation exchange capacity (CEC), base saturation (BS), and exchangeable bases (Ca2+, Mg2+, K+, and Na+). Furthermore, soil microbial respiration (SMR) was determined based on basal respiration method. The results indicated that most of the investigated soil properties showed significant difference across LUTs, among which NO3––N, total N, and K2O were profoundly affected by LUT (p ≤ 0.001). On the other hand, CEC, soil moisture, and Na+ did not greatly change among the LUTs (p ≥ 0.05). Arable soils showed the lowest SOM content and available nitrogen but the highest content of P2O5 and CaCO3. SMR was considerably higher in grassland compared to arable land and forest, respectively. The study found a positive correlation between soil moisture (r = 0.67; p < 0.01), Mg2+ (r = 0.61; p < 0.01), and K2O (r = 0.58; p < 0.05) with SMR. Overall, the study highlighted that agricultural practices in the study area induced SOM and available nitrogen reduction. Grassland soils were more favorable for microbial activity.
Authors:M. Rizk, S. Toubar, E. Ramzy, and Marwa Helmy
New, sensitive, rapid, cost-effective, and validated stability-indicating thin layer chromatographic (TLC) method coupled with fluorescence (FL) detection was developed for the quantitative analysis of celecoxib (CEL) and amlodipine besylate (AMLO) in their laboratory prepared binary mixture using the non-fluorescent TLC silica gel 60 plates. Ethyl acetate: diethylamine: 1-propanol (9:1:0.2, V/V) was used as a developing system. The retention factor (Rf) for each drug was 0.80 ± 0.03 and 0.44 ± 0.01 for CEL and AMLO, respectively. The plates were excited at 264 nm for the simultaneous FL measurement of CEL and AMLO, the calibration curves were linear over a concentration ranges of 30.0–300.0 ng/band and 15.0–150.0 ng/band with mean percentage recoveries of 99.80 ± 0.85 and 99.80 ± 0.77 For CEL and AMLO, respectively. The developed method was applied for the stability studies of the cited drugs in their laboratory prepared binary mixture and the forced degradation products were determined when present in presence of the pure drugs so the method can be considered as a stability-indicating one and it was validated as per ICH guidelines and proved to be accurate and precise.
Authors:Gulab Khan Rohela, Prasad Bylla, Sreenu Pendli, Rajender Korra, Rajender Gandu, and Christopher Reuben
Rauwolfia tetraphylla L., is an important medicinal plant in Apocynaceae family and is recognized as an alternative source to Rauwolfia serpentina L., in terms of anti-hypertensive alkaloid production i.e. reserpine. In view of this, the present study is conducted to estimate the reserpine content in different parts (leaf, stem and root) of field grown plants (2 years old), tissue cultured plantlets (R1) (two months old) and cell suspensions cultures (two months old with and without precursor feeding) of R. tetraphylla by using high performance liquid chromatography (HPLC) technique. Overall maximum content of reserpine (in %) was estimated from the root samples. Roots of field grown plants has recorded high percent of reserpine (0.39%) followed by roots of tissue cultured plantlets (0.35%) and root callus based cell suspension cultures (0.38 %) which was fed with precursor amino acid (100 mg/L of tryptophan). In control type of root callus based cell suspension cultures, reserpine content was quantified as 0.14%; by precursor feeding (100 mg/L of tryptophan) it was enhanced to 0.38%. In conclusion, the reserpine content (0.35 and 0.38%) produced by the roots of tissue cultured plantlets (R1) and 100 mg/L tryptophan fed root callus based cell suspensions was comparable to that of the reserpine content (0.39%) of root parts of field grown plants. The present study demonstrates the reserpine production by in vitro cell suspension cultures throughout the year without sacrificing the medicinal plants.
Authors:Steven Yeung, Quanlan Chen, Yongbang Yu, Bingsen Zhou, Wei Wu, Xia Li, Ying Huang, and Zhijun Wang
Ganoderma lucidum (GL), also known as Reishi or Lingzhi, is a medicinal mushroom widely used in traditional and folk medicines. The extracts made from the fruiting body and spore of naturally grown GL are the most frequently used in commercial products. More than 400 compounds have been identified in GL with the triterpenoids considered to be the major active components. Large variations in the chemical components were reported in previous studies and there is no comprehensive study of the content of multiple major triterpenoids in the GL product. In addition, there is no report in the comparison of chemical profiles in different parts of GL (i.e., fruiting body and spore). Determining the chemical composition and comparing the differences between fruiting body and spore are essential for the identity, efficacy and safety of various GL products.
In this study, 13 compounds (ganoderenic Acid C, ganoderic Acid C2, ganoderic Acid G, ganoderic Acid B, ganoderenic Acid B, ganoderic Acid A, ganoderic Acid H, ganoderenic Acid D, ganoderic Acid D, ganoderic Acid F, ganoderic Acid DM, ganoderol A, and ergosterol) were selected as the chemical markers. The purpose of this study is to develop an HPLC-DAD fingerprint method for quantification of these active components in GL (spore and fruiting body) and test the feasibility of using the HPLC-DAD fingerprint for quality control or identity determination of GL products.
The results showed that this method could determine the levels of the major components accurately and precisely. Among the 13 components, 11 ganoderma acids were identified to be proper chemical markers for quality control of GL products, while ganoderal A was in a very low amount and ergosterol was not a specific marker in GL. The extracts of fruiting body contained more chemical compounds than those of spore, indicating that these 11 compounds could be a better chemical marker for the fruiting body than the spore. The HPLC chemical fingerprint analysis showed higher variability in the quality of GL harvest in different years, while lesser variation in batches harvested in the same year.
In conclusion, an HPLC assay detecting 11 major active components and a fingerprinting method was successfully established and validated to be feasible for quality control of most commercial GL products.
Authors:Ke Ren, Tiantian Feng, Hai Shi, Jianshe Ma, and Yongxi Jin
Narciclasine is a 7-hydroxy derivative of lycorisidine. It was the first alkaloid isolated from the stem of narcissus (Amaryllidaceae) in 1967. Six mice were given narciclasine (5 mg/kg) by intravenous administration. A UPLC-MS/MS method was developed to determine narciclasine in mouse blood. Tectorigenin (internal standard, IS) and narciclasine were gradient eluted by mobile phase of methanol and 0.1% formic acid in a BEH C18 column. The multiple reaction monitoring (MRM) of m/z 308.1→248.1 for narciclasine and m/z 301.1→286.0 for IS with an electrospray ionization (ESI) source was used for quantitative determination. The calibration curve ranged from 1 to 6,000 ng/mL. The accuracy was from 92.5 to 107.3%, and the matrix effect was between 103.6 and 107.4%. The developed UPLC-MS/MS method was successfully applicated to a pharmacokinetic study of narciclasine in mice after intravenous administration (5 mg/kg).
Authors:Jovana Tomić, Nevena Djajić, Danica Agbaba, Biljana Otašević, Andjelija Malenović, and Ana Protić
This paper is aimed at developing a gradient elution reversed-phase high-performance liquid chromatography (RP-HPLC) method for the separation of a complex mixture composed of ivabradine and its eleven impurities, in a reasonable timeframe. In order to obtain a robust and reliable HPLC method for separation of this mixture, Analytical Quality by Design (AQbD) was applied. This approach demonstrated to be useful in development of a long lasting life cycle methods. Four chromatographic variables were defined as key method parameters (KMPs) and optimized towards the analytical target profile (ATP). Designated KMPs were initial and final amount of acetonitrile in the mobile phase, pH value of the aqueous phase and gradient time, while resolutions of critical peak pairs were denoted as critical method attributes (CMAs). Relationships between KMPs and CMAs were obtained with the aid of Design of Experiments (DoEs) methodology among which Box-Behnken design (BBD) was employed to gain valid mathematical models. Obtained mathematical equations were used to construct the Design Space (DS) and select reliable optimal separation conditions. They included 11% (v/v) and 34% (v/v) of initial and final amount of acetonitrile, respectively, as well as 45 min of gradient elution time and 20 mM ammonium acetate as aqueous mobile phase with pH set to 7.35. The possibility to separate the diastereoisomers of impurity X was also evaluated. It was demonstrated that this separation could not be achieved in gradient elution mode within the defined variable domains and in a reasonable time span. The developed method was validated according to ICH Q2 (R1) guideline and met all the required criteria.