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Abstract

According to World Health Organization (WHO) 10% of the medicines in the Low and Middle Income Countries (LMICs) are of poor quality posing a major public health threat. One way to circumvent such problem is the development and deployment of rapid, economical and efficient analytical methods. Hence this research aims to develop a High-Performance Thin Layer Chromatography (HPTLC) method for the determination of doxycycline hyclate. A rapid and simple HPTLC method with densitometry detection at 360 nm to determine doxycycline hyclate in capsules and tablet formulations was developed and validated. HPTLC was performed on glass plates coated with C18 reverse phase silica gel 60 F254 and pretreated with 0.27 M ethylenediaminetetraaceticacid (EDTA) solution. The mobile phase was dichloromethane: methanol: acetonitrile: 1% aqueous ammonia in the ratio of 10:22:53:15 (v/v). The linearity range lies between 200 and 1,000 ng/spot with correlation coefficient of 0.997. The Rf value is 0.5 ± 0.02%. Recoveries were in the range of 94.50–100.5%. Limit of detection and limit of quantitation values for doxycycline hyclate were 40 and 160 ng/spot respectively. The developed method was validated as per ICH guidelines. Thus, it was found to be accurate, precise, specific and robust. In forced degradation study, doxycycline hyclate was found to degrade in acidic and alkaline media, and through oxidative stress. The drug was found to be relatively stable to heat and photo degradation. The method was successfully applied for the routine quantitative analysis of dosage forms containing doxycycline hyclate. The developed method offered comparable results (as confirmed by F-test) with that of the HPLC pharmacopoeial (BP) analysis method.

Open access

Abstract

Statins drugs are thought to be among the most prescribed drugs worldwide for the treatment of hypercholesterolaemia. A simple and reliable RP-HPLC method has been successfully employed for simultaneously separating and qualifying three statin drugs including atorvastatin, rosuvastatin and simvastatin in pharmaceutical tablets. The optimal conditions were mobile phase 50:50 (v/v) (formic acid pH 2.50: ETOH), column temperature 40.00 °C, detection wavelength 238.00 nm, and flow rate 1.00 mL/min. The proposed method has been validated based on the ICH guidelines in terms of linearity, precision, accuracy, and limit of detection and limit of quantification. The linear range investigated 2.0–80.0, 4.0–100.00, and 12.00–120.00 µg/mL for rosuvastatin, atorvastatin and simvastatin respectively with coefficients of determination (R2) within the range of 0.9993–0.9995. The LOD and LOQ for rosuvastatin, atorvastatin and simvastatin were (1.57, 4.76 µg/mL), (1.87, 5.66 µg/mL), (3.46, 10.49 µg/mL) respectively. In addition, in order to evaluate the feasibility of the method developed, it was employed towards the quantification of the pharmaceutical tablets for the analytes investigated and excellent recovery was obtained.

Open access

Abstract

A new, sensitive, stability-indicating reversed-phase HPLC method was validated and applied for the simultaneous quantitation of sodium valproate and two paraben preservatives; methylparaben, and propylparaben in the liquid dosage form. Stability tests were carried out through exposure of the analyte's solution to stress conditions. Separation of the analytes was achieved on (waters) C18 Column (150 mm × 3.9 mm, 5 μm). A mixture of 0.05 M monobasic potassium phosphate pH 3.5 and acetonitrile (50:50; v/v) was applied at 1.5 ml/min flow rate and UV detection wavelength at 210 nm. The degradation products and the analytes were completely separated. The linearity was performed in the range of 50–150 % from a target concentration of 10 μg/ml propylparaben, 90 μg/ml methylparaben, and 2.88 mg/ml sodium valproate with a coefficient correlation (R2) 1.0 for methylparaben, propylparaben and sodium valproate. The validation results of the suggested method were in a good agreement with ICH guidelines. Application of the proposed method for analysis of liquid dosage forms was successfully carried out in the routine quality control process.

Open access
Acta Chromatographica
Authors: Mohammed Hamed Alqarnı, Mohamad Ayman Salkini, Prawez Alam, Mazen Talal Alanazı, Maged Saad Abdel-Kader, and Samah M. El Sohafy

Abstract

Plants secondary metabolites undergoes qualitative and quantitative variation due to environmental and growth factors. It is a crucial factor to select the proper time for collection of medicinal plants to assure maximum content of active components reflected as maximum efficacy. Olive leaves (Olea europaea L.) are known traditionally for their antidiabetic effect. The secoiridoid glycoside oleuropein is the main active component of Olive leaves responsible for the biological activity. The current study was conducted to monitor the seasonal variation of oleuropein in Olives leaves collected from the same location. To achieve this goal a validated HPLC method following the ICH guidelines was established. Separation was conducted using RP18 column and a mobile phase consisted of ultrapure water containing 20% acetonitrile and 1% acetic acid. Detection was performed at 254 nm with 1 mL/min flow rate. The method was simple, linear, accurate, precise, specific and robust. The analyses revealed considerable variations in the level of oleuropein throughout the year. This variation cannot be explained by temperature variation during the year. Two points of high levels of oleuropein were detected prior to flowering stage and ripening of the fruits. The levels of growth regulators most likely is responsible for the increased production of oleuropein. It is recommended that leaves intended for medicinal use to be collected during the fruiting stage prior to fruit ripening.

Open access
Acta Chromatographica
Authors: Gobinda Chandra Acharya, Naresh Ponnam, Meenu Kumari, Tapas Kumar Roy, Kodthalu Seetharamaiah Shivashankara, and Manas Ranjan Sahoo

Abstract

Spiny coriander (Eryngium foetidum L.) is a perennial medicinal herb grown in the tropical regions worldwide. In India, it is used as a potential spice for garnishing and flavoring the dishes and treating several ailments. Eryngium spp. found in coastal Odisha, India has a strong aroma similar to the seasonal Coriandrum. The volatile flavor constituents of the unique plants were analyzed through headspace solid-phase microextraction (HS-SPME) using capillary gas chromatography (GC) and gas chromatography-tandem mass spectrometry (GC–MS/MS). The volatile compounds exhibited high chemodiversity, with 10-undecenal as the major component in leaves (44.98%) and branches (57.43%). Fourier-transform infrared (FTIR) spectroscopy identified eight major peaks grouped into six main regions. Chemo profiles of these two corianders were overlapped and showed similar area differences in the spectral peak. The lesser-known perennial Eryngium with high chemodiversity would be a better alternative to the seasonal coriander for aromatic, pharmaceutical, and industrial uses.

Open access

Abstract

Letrozole is one of the third generation aromatase inhibitors. It is suitable for the treatment of postmenopausal patients with advanced breast cancer and early treatment of breast cancer. It is necessary to develop a rapid, reliable, selective and sensitive LC–MS/MS assay to determine letrozole in human plasma to evaluate the clinical efficacy and adverse reactions with clinical pharmacokinetic and therapeutic drug monitoring. Separation was carried out on a Kromasil-C18 column using acetonitrile-water (55: 45, v/v) as mobile phase. Detection was carried out by multiple reaction monitoring on a 3200Qtrap mass spectrometry. The method needed one-step protein precipitation procedure only, and the cycle time was 2.5 min allowing 500–550 samples per day. It was linear within 0.30–50.00 ng/mL for plasma with the limit of detection (LOD) of 0.030 ng/mL. The intra- and inter-day RSD were 5.51–8.63%, 2.28–9.95% and the RE was 0.18–1.65%. The recovery rates of letrozole and internal standard for plasma were 89.30–98.55%. Letrozole was stable under all the conditions in the study. The method was sensitive enough to quantitate letrozole over a period of 288 h after giving a single oral dose of 2.5 mg–24 Chinese healthy volunteers. The absorption of letrozole was rapid with small individual difference, the tissue distribution of letrozole was more than that in blood, and the clearance was slow. Letrozole was similar to three-compartment model in vivo. Due to metabolism and excretion, the AUCs of letrozole varied greatly among individuals.

Open access

ERRATUM: MÚLT-JELEN-JÖVŐ a hazai mezőgazdasági talajvizsgálatokban

PAST-PRESENT-FUTURE in Hungarian soil analyses

Agrokémia és Talajtan
Authors: Vona Viktória, Bakos István Attila, Giczi Zsolt, Kalocsai Renátó, Vona Márton, Kulmány István Mihály, and Centeri Csaba
Full access

Fourier-transzformációs közép-infravörös spektroszkópia alapú szervesanyag-tartalom becslés tábla szintű reprezentativitás-vizsgálata kemometriai módszerekkel

Representativity analysis of middle-infrared spectroscopy-based Organic Carbon assessment on field-scale by chemometric methods

Agrokémia és Talajtan
Authors: Tóth József Attila, Döbröntey Réka, Szegi Tamás, Michéli Erika, and Csorba Ádám

Szervesszén térképezést segítő módszertani kutatásként vizsgáltuk egy szántóföldi művelés alatt álló terület, 3 mélységből származó mintáinak MIR reflektanciáját, illetve szervesszén tartalmát (Walkley-Black). Ezt követően a spektroszkópia mérések eredményeit használtuk a talaj szervesszén-mennyiségének (TOC %) becslésére. Tettük ezt 3 mintakijelölési módszer (Kennard-Stone Sampling - KSS, K-means Sampling - KMS, Latin Hypercube Sampling - LHS) bevonásával, az így kijelölt kalibrációs mintákkal a PLSR modell segítségével becslést végeztünk az adathalmaz további értékeire. Annak érdekében, hogy tábla szintű szervesszén meghatározás során teszteljük becslési pontosságukat, a modellek reprezentativitását – különböző validációs/kalibrációs arány esetén – statisztikai mutatókkal (R2, RMSE) ellenőriztük.

Az eredményekben részleteiben vizsgáltuk a különböző becslési modellek reakcióját eltérő arányú kalibráció és validáció esetén. A modellek R2 és RMSE értékei alapján kijelöltük, hogy mely modellek működtek pontosan még alacsony kalibráció esetén is, illetve abszolút értelemben véve melyik modell volt leghatékonyabb.

Az összehasonlítás eredményeként kijelenthető, hogy az általunk vizsgált talajkörülmények között a 30% alatti, valamint a 70% feletti mintaszámú kalibráció a mintakijelölési módszerek megbízhatóságának ingadozását eredményezte. Az összes minta 30%-val történő kalibráció esetén legjobb eredményt a KSS adta, így ez tekinthető a leggazdaságosabb módszernek. Az abszolút értékben vett legkisebb hibát a K-means sampling eredményezte, a minták 90%-val történő kalibrációt követően.

Kijelenthető, hogy az alkalmazott módszertan esetünkben alkalmas volt – a reprezentativitás megtartása mellett – a szükséges minták számának, ergo a táblaszintű szervesszén-felmérés költségeinek csökkentésére. Továbbá a mintakijelölési módszerek becslési hatékonyságának összehasonlítására is megfelelt az általunk alkalmazott statisztikai vizsgálat. A módszertan a jövőben kiinduló alapja lehet hasonló jellegű kutatásoknak, valamint tábla szintű szervesszéntérképek elkészítésének. A szélesebb körű alkalmazást megelőzően a modelleket nagyobb varianciájú adathalmazok esetén is tesztelni szükséges.

Within the framework of the present research, we mapped the organic carbon content of an arable area, during which we measured the MIR reflectance and organic carbon content (Walkley-Black) of the soil samples collected from the area at three different depths. Subsequently, the results of spectroscopic measurements were used to improve the estimation of the soil organic carbon content (TOC %). Three sample selection models were involved (KSS, KMS, LHS), and with the selected calibration samples, we estimated the additional values of the data set using the PLSR model. In order to test the accuracy of estimation for a table-level organic carbon determination, the representativeness level of the models was checked with statistical indicators (R2, RMSE) at different validation / calibration ratios.

In the results, we thoroughly examined the response of different estimation models with different ratios of calibration and validation. Based on the R2 and RMSE values of the models, we determined which models worked precisely even at low calibration, and in absolute terms, which model was the most efficient.

As a result of the comparison, it can be stated that under the soil conditions we examined, calibration with a sample number below 30% and above 70% caused significant fluctuations in the reliability of the sampling methods. Kennard-Stone sampling (KSS) gave the most precise results for calibration with 30% of all samples, thus it is considered the most economical method. The smallest error overall was given by K-means sampling after calibration of 90% of the samples.

It can be stated that the methodology used in this study was suitable to reduce the samples required for analysis - while maintaining representativeness - therefore reducing the costs of the field-level organic carbon survey.

Furthermore, the statistical analysis we used to compare the estimation efficiency of the sampling methods was also appropriate. The methodology we use may be the basis for similar research in the future, as well as for the production of table-level organic carbon maps. Prior to wider application, models also need to be tested for higher variance datasets.

Open access

Szennyvíziszap kihelyezés rövidtávú következményeinek értékelési lehetősége Sentinel-2 alapú szántóföldi vegetációmonitoring alapján

Evaluate the short-term effects of sewage sludge disposal based on Sentinel-2 vegetation monitoring

Agrokémia és Talajtan
Authors: Kovács Ferenc and Ladányi Zsuzsanna

Az iszapkihelyezések rövidtávú hatásainak megfigyelésére és igazolására több évre kiterjedő, nagy időfelbontású monitoringot terveztünk dél-alföldi, csernozjom talajokon folyamatosan művelt, gyakran évről-évre különböző növényzettel fedett szántóföldi parcellákon. A 14 db 50 m x 50 m-es kvadráton, a Sentinel-2 műholdfelvételezés alapú adatgyűjtést a legnagyobb idő- és térbeli felbontásban alkalmaztuk. Atmoszférikus korrekcióval előfeldolgozott, közel 100 db felhőmentes képből álló adatbázist LANDSAT OLI (Operational Land Imager) felvételekkel kiegészítve, vegetációs indexekkel (EVI, NDVI) értékeltük a nyári félév fotoszintetikus aktivitását és biomassza-produkció változásait térben és időben.

A spektrális index alapú vegetációs ciklus különbségek alapján meghatározhatók a területen termelt változatos növényfajok, a felszínfedettség különbségek és a területhasználati változások. A vizsgálatainkkal párhuzamosan, LADÁNYI et al., (2020) szerint értékelt talajtani eredményekhez hasonlóan az iszapkihelyezés által érintett, illetve nem érintett területek között kimutatható, EVI és NDVI-vel mért statisztikai és térbeli különbségek rövidtávon általánosan nem szignifikánsak. A vizsgált négy termény közül a napraforgó, kukorica biomassza produktuma esetén láthatók index különbségek, amelyek az iszapkihelyezés 1–3 éven belül tapasztalható hatásaként értékelhetők, de ennek igazolására folyamatos monitoring vizsgálat szükséges. A repce és az őszi búza esetén a rendelkezésre álló adatok alapján nem tapasztaltunk hasonlót, sőt esetenként a kihelyezés előtti VI értékek magasabbak. A parcellákat jellemző térbeli heterogenitáson – melyet a kvadrátok jól mintáznak – a szennyvíziszap kihelyezések a vizsgált időszakban nem változtattak.

A két különböző vegetációs index együttes alkalmazása hasznos. Az EVI általános előnyei mellett kiemelhető a dús vegetációs időszak értékelésének pontossága, az összehasonlító elemzésben tapasztalható alkalmazhatósága, míg az NDVI a csekélyebb vegetáció dinamikájában, a vegetációtípusok megkülönböztetésében, vagy a dús vegetációt jellemző változékonyság megfigyelésében lehet érzékenyebb. Érdekes, hogy az NDVI és EVI közötti különbség a szennyvíziszappal kezelt területeken kisebb. A várakozásnak megfelelően, a nagy felbontást igénylő vizsgálatban a LANDSAT adatok, a Sentinel alapú indexértékekkel általánosan szoros statisztikai kapcsolatban vannak és igazolják az értékelés eredményeit, de a parcellákon, adott időkben tapasztalt jelentős eltérések miatt önmagukban nem tudják kiegészíteni a vizsgálatot.

A gazdálkodásváltás ellenére kitűzött cél, a szignifikáns különbségek kimutatása indokolja az aktuális évek adatainak további vizsgálatba való bevonását, amely segít az adathiányos időszakok leszűkítésében is; 2020. év megfigyelése folyamatban van.

The agricultural use of sewage sludge is one of the means of refilling the soil nutrients and an effective tool for sustainable environmental management. In order to monitor and verify the short-term effects of sludge disposal (in parallel with other soil observations) we planned a multi-year, high-resolution data collection for monitoring the effects of disposal in some arable land parcels on 14 pieces of 50 m x 50 m quadrates in southeastern Hungary. Using free Sentinel-2, pre-processed satellite imagery, data acquisition was applied at the highest temporal and spatial resolution supplemented with LANDSAT-8 recordings, evaluating the vegetation period from 2016 to 2019 (almost 100 images). We evaluated the photosynthetic activity of the summer season and the changes in biomass production in space and time based on vegetation index (EVI, NDVI).

The difference in the vegetation cycle of the plants on the arable land and the difference in the land use and land cover (LU/LC) are clearly visible in the values of EVI and NDVI. The statistical and spatial index differences between the affected and non-affected areas of sludge disposal are generally not significant in the short term. It can be seen differences in the case of the sunflower and maize biomass products. These can be assessed as the effect of sludge disposal within 1–3 years, but continuous monitoring is required to verify this. In the case of colza and winter wheat (based on the available data) we did not find similar effects, and in some cases the pre-placement EVI/NDVI values were higher.

Vegetation indices heterogeneity among the parcels is also well patterned spatially in the quadrates. The spatial heterogeneity characteristic of the quadrates was not changed by the sewage sludge disposal over the study period. Geometric resolution and monitoring can be used to map a former alluvial form, which is an important factor in understanding parcel yield changes.

We can emphasize the accuracy of EVI evaluation in the dense vegetation period and its applicability in a comparative analysis. NDVI may be more sensitive in the dynamics of smaller or sparse vegetation, or sometimes in the observation of variability characteristic of rich vegetation. It is interesting, that the difference between NDVI and EVI is smaller in areas treated with sewage sludge. LANDSAT data are generally closely related to the Sentinel-based indices values and confirm the results of their evaluation, but they cannot supplement the study on their own due to the significant differences on the parcels at certain times.

In addition to the change of agricultural management, in the detection of significant differences, it is appropriate to measure the data for the following years, that can help to narrow down the data deficient periods; monitoring for 2020 is in progress.

Open access