This paper includes the development of a novel, systematic, quality by design (QbD)-based high-performance thin-layer chromatography (HPTLC) method for the simultaneous estimation of torsemide and eplerenone. Chromatographic separation was carried out on aluminum-backed silica gel 60 F254 plates using toluene-ethyl acetate-glacial acetic acid (7:3:0.1, V/V) as the mobile phase. UV detection was carried out at 297 nm for torsemide and 247 nm for eplerenone. A 3-factor 17-run regular 3-level factorial design was applied to factor screening studies, and Box–Behnken design was utilized for optimization of the experimental parameters of HPTLC for obtaining anticipated chromatographic conditions. Risk assessment was executed to understand the basic method parameters. From the risk assessment, 3 independent parameters, such as band length, saturation time, and wavelength, were selected and studied for the impact of these 3 parameters on the responses. The method yields compact and well-resolved band at RF = 0.24 ± 0.02 for torsemide and RF = 0.50 ± 0.02 for eplerenone. In the linear regression analysis carried out for torsemide and eplerenone, the regression coefficient was found to be r2 = 0.999 for torsemide and r2 =0.995 for eplerenone. The method was validated for validation parameters like accuracy, precision, robustness, limit of detection, and limit of quantification as per the International Conference on Harmonization (ICH) guidelines.
A new reversed-phase high-performance liquid chromatographic method with ultraviolet detection (RP-HPLC-UV) for simultaneous determination of phenytoin impurities, benzophenone and benzil, was developed and validated according to the International Council for Harmonization (ICH) guidelines. Chromatographic separation was performed on a C8 column using acetonitrile–1% acetic acid (60:40, v/v). The correlation coefficients of the calibration lines were greater than 0.999 with 95% confident interval of y-intercept over the origin. The analytical method showed good precision, intra-day precision ≤1.00 and inter-day precision ≤1.53. The standard solution of each compound exhibited good stability 99.18–99.70%, after storage at room temperature for 24 h. The limit of detection (LOD) and limit of quantification (LOQ) were 0.0015 and 0.005 μg/mL, respectively. The resolution of the impurities was 2.935 ± 0.009. The proposed analytical method was successfully applied to determine the amount of benzophenone and benzil in marketed products. The amount of benzophenone was found at 3.09–5.91 × 10−3%, while benzil was not detected in the samples.
Genotoxic impurities can be described as impurities that can induce genetic mutations and chromosomal breaks, or that damage the genetic information within a cell, which may lead to cancer. The European Medical Agency (EMA) and the United States Food and Drug Administration (US FDA) have set a threshold of toxicological concern (TTC) of genotoxic impurities 1.5 µg per day. In a continuous effort to develop an analytical method for the estimation of genotoxic impurities in quetiapine fumarate, a sensitive, simple, and precise high-performance thin-layer chromatography method has been developed and validated for the determination of 2-nitrophenyl (phenyl)sulfane as a genotoxic impurity at trace levels. The limits of detection (LOD) for quetiapine fumarate and 2-nitrophenyl (phenyl)sulfane were found to be 5.11 and 15.5 ng per band, whereas the limits of quantification (LOQ) were observed 0.09 and 0.3 ng per band, respectively. The calibration curve for 2-nitrophenyl (phenyl)sulfane was linear over the concentration range of 10 to 50 ng per band. The method was found to be specific, precise, linear, and accurate for the estimation of 2-nitrophenyl (phenyl)sulfane at trace levels in quetiapine fumarate.
The present study aimed to develop and validate an analytical method for determination of marbofloxacin (MAR) in veterinary chewable tablets. The isocratic reversed-phase chromatographic method was developed and validated using a Vertisep®, RP C18 column (150 mm × 4.6 mm, 5.0 μm). The mobile phase was composed of water–acetonitrile (55:45, v/v) with pH adjusted to 3.0 with ortho-phosphoric acid and a flow rate set at 0.4 mL/min. The proposed method was validated for linearity in a concentration range of 2.5 to 17.5 μg/mL with a correlation coefficient of 0.99991. The mean content of MAR found in chewable tablets was 104.40% with RSD below 2%. The accuracy expressed as average recovery of the proposed method was 98.74%, and the precision expressed as relative standard deviation among repeated analysis was 0.55%. The method has adequate sensitivity with detection and quantitation limits of 0.25 and 0.81 μg/mL, respectively. Based on the presented results and according to the ICH and AOAC guidelines on validation of analytical methods, the proposed method was considered precise, accurate with adequate sensitivity, and robust in the MAR quantitative analysis. Therefore, the method can be used in the quality control of chewable veterinary tablets containing MAR.
Adaptation is the most important strategy to reduce the effect of climate change and soil erosion. During this process adequate, rational land use is necessary to ensure climate resilience. Therefore, the main objective in this study was to evaluate the susceptibility of different land use intensities (arable land and grassland) to soil erosion. The rainfall simulation method is a good tool to measure and estimate soil erosion in situ. The comparative measurements were carried out in the field with a Shower Power-02 simulator on 6 m2 plots in Gerézdpuszta, where the slope angles were ~8% and the simulated rainfall events had high intensities (~70-96 mm h−1). The runoff and soil loss were significantly higher from arable land. The runoff-infiltration ratio and runoff coefficient showed lower infiltration capacity in the case of arable land. On average, the suspended sediment loads were tenfold higher under intensive land use. In the case of grassland a moderate increase in infiltration was observed due to higher rainfall intensity, as also reported in the literature. The rainfall simulation method provides good data for soil loss estimations.
A reliable method using disposable pipette extraction (DPX) based on composite of pernigraniline and styrene–divinylbenzene (Sty–DVB) copolymer was applied to the analysis of dexamethasone in synovial fluid using high-performance liquid chromatography and ultraviolet (UV) detector (HPLC–UV).
DPX variables, namely, number of draw/eject cycles for extraction or desorption, sample pH, volume, and desorption solvent, were optimized to establish the best sorption equilibrium and analysis time. The highest extraction efficiency value was obtained with 50 μL of synovial fluid mixed with 1950 μL of water, in five cycles of 300 μL of sampling, followed by liquid desorption of the drug with 300 μL of methanol in three cycles. The developed method demonstrated a linear response over the range from 10 to 100 ng/mL, with R2 = 0.993. The limit of quantification (LOQ) was 10 ng/mL. Based on the validation results, the proposed method can be a useful tool to detect dexamethasone levels in synovial fluid.
Hungary was one of the main countries in the world as regards the yields reached in maize production. The research was conducted to appraise the effect of NPK fertilizer on traits of different hybrid maize (Fao410, Fao340) at the University of Debrecen and our experiment was carried out in Centre for Agricultural Sciences, Institute of Crop Sciences at Látókép in 2018. NPK fertilizer was applied in six different combinations (0-0-0 control, 30-23-27 first dose, 60-46-54 second dose, 90-69-81 third dose, 120-92-108 fourth dose and 150-115-135 fifth dose kg · ha−1). The result of compound variance showed the level of fertilizer and interaction between fertilizer and genotypes were significant in one percent. Effect of genotypes was a variable level of fertilizer and providing a different yield in the level of fertilizer. The weight of seeds in ear and weight of ear were important traits in the average yield on Fao410 hybrid. Also, the fourth of the fertilizer level was the best level of fertilizer for yield on Fao410 and Fao340. the weight of fresh plant and weight of seeds in ear were highest relation with yield in H340 hybrid. The results of this research can successfully contribute to the science of maize cultivars, the given adapted hybrid to the discovery of their traits and to an application of fertilizers.