Browse

You are looking at 11 - 20 of 1,223 items for :

  • Chemistry and Chemical Engineering x
  • Refine by Access: Content accessible to me x
Clear All

Abstract

This study aims to predict drought periods affecting the Tokaj-Hegyalja wine region and the application of this in crop protection. The Tokaj-Hegyalja wine region is the only closed wine region in Hungary with a specific mesoclimate and a corresponding wine grape variety composition, in which climate change strongly threatens cultivation. The probability that a randomly selected day in the vegetation period will fall into a drought period in the future was estimated using the daily precipitation amount and daily maximum temperature data from the Hungarian Meteorological Service for the period 2002–2020. The Markov model, a relatively new mathematical method for the statistical investigation of weather phenomena, was used for this. Markov chains can, therefore, be a valuable tool for organizing integrated pest management. This can be used to plan irrigation, control fungal pathogens infecting the vines, and plan the success of a given vintage.

Open access

Abstract

In accordance with the International Coordinating Committee's recommendations, an acceptable UPLC-MS method is being developed for analyzing Relugolix stability under various stress scenarios. Stress conditions included exposure to 0.1 and 1 N acid, alkali, hydrolysis, peroxide, light, reduction, and heat. The mobile phase for this analysis was prepared by blending acetonitrile and a 0.1% orthophosphate solution in a 50:50 (v/v) ratio. A C18 Column with dimensions of 100 × 2.1 mm and a particle size of 1.7 µm was employed as the stationary phase. The wavelength at which detection was performed was 247 nm, and the flow rate was maintained stable at 0.5 mL min−1. Strong linearity was shown by this method across a concentration range of 1.25 μg mL−1 to 7.5 μg mL−1. The method's reliability was shown by ensuring all of the validation parameters fell within the acceptable range.

Furthermore, forced degradation studies were conducted using standard drugs. Different stress conditions led to the formation of degradation products, which were successfully separated from Relugolix using the C18 column in combination with an auto-purification mass spectrometer. Among the stress conditions, alkaline conditions showed a lower degradation rate. Interestingly, seven distinct types of degradation products were identified from the degradation studies under acid, alkali, hydrolysis, hydrogen peroxide, light, reduction, and thermal conditions. Remarkably, these seven degradation products have not been reported in previous literature, making this study the first to document their existence.

Open access

Abstract

The utilization of sea buckthorn pomace (SBP) is attracting growing attention since it is valuable industrial waste. This pomace can find usage as a functional ingredient of food because it contains bioactive, health-promoting components, but to our knowledge, few scientists have so far studied utilization of the antimicrobial activity of fruit pomace. The study aims are to broaden our knowledge of antioxidant and antimicrobial status of SBP by utilizing pomace as a functional apple juice ingredient and by monitoring the antioxidant capacity, the total polyphenol content and microbial changes that occur during the storage of juice samples. Our results of this study highlight that the importance of the utilization of SBP because the results reported here provide further evidence that SBP can contribute to increasing the content of valuable components in apple juice samples and inhibiting the growth of microorganisms during storage.

Open access

Abstract

This study deals with the development of HPLC assay method for the determination of guaifenesin (GUF), bromhexine (BRH), chlorpheniramine (CHP), and dextromethorphan (DEE) in bulk and Leekuf tablets. Column C18 Aligent eclipse was used to analyse GUF, BRH, CHP and DEE. The H3PO4 (0.01%) and methanol combined in 70:50 (vol/vol) parts was used as mobile phase. The HPLC assay method was validated in accordance with the ICH prerequisite and was capable of providing accurate (99.90% recovery for BRH, 99.40% recovery for CHP, 100.00% recovery for GUF and 99.50% for DEE) and precise (0.160–0.805% RSD range for GUF, BRH, CHP and DEE) quantitative results under slight variations in chromatographic circumstances in the range of quantities 25–150 μg mL−1 (GUF), 2–12 μg mL−1 (BRH), 0.5–3 μg mL−1 (CHP) and 2.5–15 μg mL−1 (DEE). These results concluded that HPLC assay method developed was beneficial for the evaluation of GUF, BRH, CHP and DEE simultaneously in commercial tablet dose. The degradants eluted are well resolved from the GUF, BRH, CHP, and DEE peaks, showing that the process is stability indicating.

Open access

Abstract

Objective

To establish a method for the high-performance liquid chromatography (HPLC) fingerprint and content determination of Wuwei Zhenju Tablets, and combine with chemical pattern recognition analysis to provide basis for its quality evalution.

Methods

Based on HPLC, taking the chromatographic peak of puerarin as the reference peak, the fingerprints of 10 batches of Wuwei Zhenju Tablets were established and the similarity evaluation was carried out to determine the common peaks. SPSS 26.0 and SIMCA 14.1 software were used to evaluate the overall quality of Zhenju Tablets by cluster analysis and principal component analysis. The contents of chlorogenic acid, puerarin, daidzin, isochlorogenic acid B, isochlorogenic acid A and aurantio-obtusin in the samples were determined by the same method.

Results

Twenty-six common peaks were identified in the fingerprints of 10 batches of Wuwei Zhenju Tablets, and the similarity evaluation was greater than 0.985. Ten chromatographic peaks were identified as neochlorogenic acid, chlorogenic acid, caffeic acid, puerarin, daidzin, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, aurantio-obtusin and betaine. Combined with cluster analysis and principal component analysis, 10 batches of samples can be clustered into two categories, which can distinguish different Zhenju tablets. The model established in pattern recognition research can accurately identify Wuwei Zhenju tablets, and the prediction results are ideal. The six index components had a good linear relationship in their respective concentration ranges. The contents of chlorogenic acid, puerarin, daidzin, isochlorogenic acid B, isochlorogenic acid A and aurantio-obtusin in 10 batches of Wuwei Zhenju Tablets were 2.902–5.819, 3.693–49.680, 1.449–10.654, 2.768–7.724, 2.941–6.343 and 0.071–0.089 mg g−1, respectively.

Conclusion

The HPLC fingerprint and multi-component content determination method of Wuwei Zhenju Tablets were established for the first time. The method is simple, efficient and accurate, and can effectively provide experimental basis for the quality control and evaluation of the preparation.

Open access

Az erdőállományok talajvíz utánpótlódásra gyakorolt hatásának vizsgálata kecskemét-ménteleki mintaterületen

Investigation of the impact of forest stands on groundwater recharge in the Kecskemét-Méntelek study area

Agrokémia és Talajtan
Authors:
András Szabó
,
Zoltán Gribovszki
,
Péter Kalicz
,
Ján Szolgay
,
Zsolt Gácsi
, and
Bence Bolla

Az Alföldet, azon belül is különösen a Homokhátságot érintő talajvízszint süllyedés, súlyos ökológiai és gazdasági következményekkel is járó problémakör. A jelenség hátterében álló lehetséges okokkal kapcsolatban több évtizede zajlik kutatómunka, ugyanakkor ezek relatív súlyának meghatározása a mai napig tudományos vita tárgyát képezi.

Több szerző is kiemeli az erdőtelepítések talajvízszint csökkentő hatásának fontosságát. Ez a hatás két módon, a vegetáció vízfelvétele, illetve a csapadékból történő utánpótlódás csökkentése (intercepció, talajnedvesség felvétel) által jelentkezhet. Ezen mechanizmusok működését vizsgáltuk meg egy akác (Robinia pseudoacacia) és egy fekete fenyő (Pinus nigra) állomány esetében a Homokhátságon, Kecskemét-Ménteleken kialakított mintaterületünkön, 90, 150 és 200 cm-es mélységben, nagy időbeli felbontással mért talajnedvesség, illetve talajvíz adatokra alapozva.

Az adatok alapján feltételezhető, hogy a talajvízből nem történik közvetlen, vagy közvetett vízfelvétel, aminek oka vélhetően a gyökérzóna és a talajvíz közti igen jelentős horizontális távolság. A talajnedvesség esetében a sekélyebb rétegekben egyértelműen jelentkezik az erdőállományok szezonális szárító hatása. Ugyanakkor a mélyebb rétegek talajnedvesség adatai alapján kijelenthető, hogy a csapadékból történő talajvíz visszatöltődésre leginkább az akác állomány alatt van elméleti lehetőség. A látszólagos ellentmondás feltételezhetően a gyökérzet által kialakított makropórusok hatásával magyarázható. Ezt támasztja alá az akác és fekete fenyő állományok közti igen jelentős eltérés is.

Következtetésünk, hogy az erdőállományok lokálisan jelentősen eltérő hatást gyakorolhatnak a talajvízszintre. Ezért a lezajló folyamatok hátterét, általános jellegű megállapítások helyett, az adott hidrológiai rendszer több elemét vizsgáló monitoring adataira alapozva lehetséges csak felderíteni.

Open access
Acta Chromatographica
Authors:
Waqar Siddique
,
Zulcaif
,
Hassaan Umar
,
Sufyan Junaid Usmani
,
Muhammad Waqas
,
Maria Gul
, and
Mubashra Gul

Abstract

The prevalence of diabetes is increasing day by day as per a report by the year 2045, 1 out of every 8th individuals may suffer from diabetes. This research article focuses on developing and validating Metformin and Dapagliflozin in combination by using high-pressure liquid Chromatography (RP-HPLC). The validation of the method was followed as per the guidelines provided by the International Conference on Harmonization (ICH) and United States Pharmacopeia (USP). Separation of both drugs takes place in less than 4 min. This separation takes place using Phosphate buffer (pH 6.8) and acetonitrile in a 45:55 (v/v) ratio at a 1.0 mL min−1 flow rate. Furthermore, studies on both drugs were conducted by using the bulk and pharmaceutical dosage forms (Tablets). The developed method was accurate as drug recoveries in both cases of Metformin, and Dapagliflozin ranged between (100.8, 99.6, 98.8%) to (100.8, 99.3, and 101.5%) respectively having a concentration range of solutions between 70, 100 and 130 μg mL−1 dilution. The recommended method for simultaneous quantification of Metformin and Dapagliflozin was established and validated and no excipient interactions were found.

Open access

Abstract

Microencapsulation of flaxseed oil (FO) has received lots of attention in the food and biopharmaceutical industries. To produce FO microcapsules, aqueous emulsions of FO with polymeric carbohydrates (maltodextrin (MD) with dextrose equivalent (DE) 19, gum Arabic (GA) and modified starch (MS)) were prepared by a rotor stator homogenization and subsequently, dehydration of emulsions were performed by spray drying (SD). The objective of this research was to study the effects of different combinations of polymeric carbohydrates with FO in emulsion to obtain maximum encapsulation efficiency (EE). A 3 factorials–3 levels Box–Behnken design was used for the optimization purpose. The maximum EE was achieved using 0.79 MD-GA ratio, 20.23% MS and 24.62% FO in emulsion. Microcapsules obtained by optimum condition had EE 77.68%, particle size (D 32) 120.0 ± 0.43 μm, moisture content1.6 ± 0.13%, wettability 192 ± 5.5 s, solubility 75.49 ± 1.3%, bulk density 0.31 ± 0.025 g mL−1, tapped density 0.36 ± 0.01 g mL−1, Carr's Index 13.88 ± 0.01% and Hausner Ratio 1.16 ± 0.01.

Open access

Abstract

During the testing of laboratory Voriconazole API batches, one unidentified impurity (IMP-5.312) was detected employing the Pharmeuropa HPLC technique at a level in excess of 0.10%. This IMP-5.312 was synthesized and then characterized as 6-(3-(2,4-difluorophenyl)-3-hydroxy-4-(1H-1,2,4-triazol-1-yl) butan-2-yl)-5-fluoropyrimidin-4-ol by the corresponding spectral information (MS, 1H-NMR, 13C-NMR, and IR). The IMP-5.312 impurity was effectively quantified using an enhanced HPLC based-technique that was developed as well as validated. The approach made use of a Novapak C18 column with an inner diameter of 3.9 mm and a length of 150 mm (4.0 µm) for chromatographic separation. The analysis of IMP-5.312 was made at 45 °C, with a flow rate (isocratic) of 1.0 mL min−1 and a 256 nm detection wavelength. Acetonitrile, methanol, and 0.1% aqueous trifluoro acetate buffer (pH 4.0) were mixed at a ratio of 15:30:55 (v/v/v) to create the mobile phase for a 20 μL sample injection. The linearity range of 0.25281–1.51690 μg mL−1 had a correlation coefficient more than 0.99942, and the accuracy ranged from 89.3 to 100.3%. It was noted that the established HPLC based-technique was sensitive, specific, and precise. The technique was executed on the current batches of VRC API for IMP-5.312 analysis, and the outcomes were good. For quality control purposes during the manufacturing procedure of VRC, the identification as well as analysis of IMP-5.312 should be helpful. The in silico approach was applied to predict the IMP-5.312 toxicity. The reports indicated that IMP-5.312 in non-mutagenic and categorized as ICH M7 class-5 impurity.

Open access

Abstract

In this investigation, a rapid and reliable ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique was developed for quantification of veliparib in rat plasma and used the method to study the pharmacokinetics and bioavailability of veliparib in rats after oral (6 mg kg−1) and intravenous (2 mg kg−1) administration. Plasma samples were protein precipitated with acetonitrile using midazolam as internal standard. A UPLC HSS T3 chromatographic column was utilized for separation, with a mobile phase consisting of methanol-water-formic acid in gradient elution procedure. Quantitative analysis was performed using multiple reaction monitoring in electrospray positive-ion mode. Veliparib exhibited excellent linearity within the 1–1,000 ng mL−1 range (r > 0.99). The intra- and inter-day precision of veliparib were both within 15%, and the accuracy ranged from 93.7 to 107.7%. The average recovery was above 86%, and the matrix effect was 89.0–95.8%. The AUC(0-t) values for oral and intravenous administration were 1014.7 ± 42.9 and 647.2 ± 85.2 h ng mL−1, respectively, resulting in a bioavailability of 52.3%. The UPLC-MS/MS method established in this study featured a low sample injection volume, a low quantification limit, a short chromatographic runtime, high sensitivity, and selectivity. The developed method can be used for the pharmacokinetic analysis of veliparib in both preclinical and clinical studies.

Open access