Regression Coefficient R2 Research Articles

Use of a Biopolymer for Road Pavement Subgrade

This paper presents an extensive series of laboratory works and a prediction model on the design of a road pavement subgrade with Xanthan Gum (XG) biopolymer. The experimental works were carried out using mixtures of conventional aggregate for road pavement construction and XG at the ratios of 0%, 1%, 2%, and 5%, by dry weight. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted during the experimental works at the end of the various curing periods (4, 8, 16, and 32 days). An example of an improvement in the UCS values for a specimen with 5% XG addition tested at the end of 4-daycuring yields about a 200% increment by the end of a 32-daycuring. The CBR values of clean aggregates were found to be increased by about 300% by 5% XG addition for all curing periods applied. Furthermore, the energy absorption capacity of the aggregates was observed to be increased significantly by both XG inclusion and curing period. Moreover, scaled conjugate gradient (SCG) training algorithm-based models developed for the prediction of CBR and UCS test results displayed a very high estimation performance with the regression coefficients of R2 = 0.967 and R2 = 0.987, respectively. Evidently, XG biopolymer is provably of use as an alternative inclusion in road pavement subgrades constructed with conventional aggregates.

THE DEVELOPMENT AND VALIDATION OF A FAST STABILITY INDICATING RP-HPLC METHOD FOR QUANTIFICATION OF LUMEFANTRINE AND ITS ORGANIC IMPURITIES USING CENTRAL COMPOSITE EXPERIMENTAL DESIGN

Objective: The objective of the present study was to develop and validate a stability indicating RP-HPLC method for Lumefantrine (LF) and its organic impurities using a central composite design (CCD). Methods: A specific, simple quality control friendly isocratic elution method using reverse phase HPLC was developed for quantification of Lumefantrine (LF) and its organic impurities at a wavelength of 265 nm. The chromatographic separation was achieved on the column of Thermo Hypersil ODS C18 (150x4.6 mm, 3µ) with a buffer containing 0.1percent formic acid and acetonitrile 10:90 v/v as a mobile phase with a flow rate of 1.6 ml/min at 35 °C with a run time of 10 min. Based on the preliminary trials, CCD was employed to check the effect of independent variables such as Acetonitrile ratio (A), Flow rate (B), and Column oven temperature (C). While resolution between Lumefantrine (LF) and Impurity-A (X1), Impurity-A and Impurity-B (X2), and Plate count of Lumefantrine (LF) (X3) were considered as dependent variables and statistical evaluation performed by using design expert software. The optimized conditions were validated as per ICH guidelines. Results: The retention time of LF and its organic impurities were 1.9 min, 3.0, 4.5, and 6.4 min, respectively. Design space was established and desirability was found. LOD and LOQ for the Lumefantrine (LF) and its impurities were established with respect to test concentration. The plotted calibration curves were linear with a regression coefficient of R2>0.99, indicating that the linearity was within the limit. As a part of method validation, the parameters like Specificity with forced degradation, Linearity, Precision, Accuracy, Ruggedness, and Robustness were determined and the results were found to be within the allowable limits. Conclusion: The method developed and validated was found to be suitable for routine analysis and to be used for the measurement of Lumefantrine and its impurities. Since there is no stability indicating the RP-HPLC method with design space was reported in the literature, there is a need to develop quantitative methods under different conditions to achieve improvement in specificity and selectivity.

Eco-Friendly Electroless Template Synthesis of Cu-Based Composite Track-Etched Membranes for Sorption Removal of Lead(II) Ions

This paper reports the synthesis of composite track-etched membranes (TeMs) modified with electrolessly deposited copper microtubules using copper deposition baths based on environmentally friendly and non-toxic reducing agents (ascorbic acid (Asc), glyoxylic acid (Gly), and dimethylamine borane (DMAB)), and comparative testing of their lead(II) ion removal capacity via batch adsorption experiments. The structure and composition of the composites were investigated by X-ray diffraction technique and scanning electron and atomic force microscopies. The optimal conditions for copper electroless plating were determined. The adsorption kinetics followed a pseudo-second-order kinetic model, which indicates that adsorption is controlled by the chemisorption process. A comparative study was conducted on the applicability of the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption models to define the equilibrium isotherms and the isotherm constants for the prepared composite TeMs. Based on the regression coefficients R2, it has been shown that the Freundlich model better describes the experimental data of the composite TeMs on the adsorption of lead(II) ions.

Structure-activity relationships of dihydropyrimidone inhibitors against native and auto-processed human neutrophil elastase

BackgroundHuman neutrophil elastase (HNE) is a key driver of systemic and cardiopulmonary inflammation. Recent studies have established the existence of a pathologically active auto-processed form of HNE with reduced binding affinity against small molecule inhibitors. MethodAutoDock Vina v1.2.0 and Cresset Forge v10 software were used to develop a 3D-QSAR model for a series of 47 DHPI inhibitors. Molecular Dynamics (MD) simulations were carried out using AMBER v18 to study the structure and dynamics of sc (single-chain HNE) and tcHNE (two-chain HNE). MMPBSA binding free energies of the previously reported clinical candidate BAY 85–8501 and the highly active BAY-8040 were calculated with sc and tcHNE. ResultsThe DHPI inhibitors occupy the S1 and S2 subsites of scHNE. The robust 3D-QSAR model showed acceptable predictive and descriptive capability with regression coefficient of r2 = 0.995 and cross-validation regression coefficient q2 = 0.579 for the training set. The key descriptors of shape, hydrophobics and electrostatics were mapped to the inhibitory activity. In auto-processed tcHNE, the S1 subsite undergoes widening and disruption. All the DHPI inhibitors docked with the broadened S1′-S2′ subsites of tcHNE with lower AutoDock binding affinities. The MMPBSA binding free energy of BAY-8040 with tcHNE reduced in comparison with scHNE while the clinical candidate BAY 85–8501 dissociated during MD. Thus, BAY-8040 may have lower inhibitory activity against tcHNE whereas the clinical candidate BAY 85–8501 is likely to be inactive. ConclusionSAR insights gained from this study will aid the future development of inhibitors active against both forms of HNE.

Simple isocratic RP-UHPLC-MS methods for the determination of steviols and its glycosides: Quality control perspectives

Stevia is well-known for its unique non-caloric intense sweetness and recognising as one of the most acceptable sweeteners. Therefore, quality control and metabolite profiling perspectives, two isocratic reverse-phase UPLC-PDA-ELSD-MS methods were developed to determine nine diterpene glycosides (method A) and isomeric compounds (steviol and isosteviol; method B). Both the methods were validated and found as per the ICH guidelines for accuracy (recovery), precision (Intraday, interday, and intermediate precision), linearity, and regression coefficient (r2), ruggedness (eluent concentration ± 2 mM, column oven temperature ± 3 °C and retention time), and system suitability (theoretical plate count, asymmetric factor, injection precision and resolution). LOD for steviol and its glycosides were found between 0.92 and 5.22 μg/mL while LOQ were 2.78–18.29 μg/mL, respectively. Validated methods had shown only the presence of steviol glycosides in Stevia rebaudina samples while LC-ESI-MS/MS revealed the identification of 46 different class of molecules. These methods will be helpful to monitor quality in Stevia production and its derived products.

Removal of lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar adsorbent

Antiviral drugs such as lamivudine have been globally identified in the environment and marked as emerging pollutants of concern due to their bioactive extremity. Following therapeutic uses, approximately 70% of the oral dose of lamivudine is eliminated renally as the parent drug. Concerns has been raised for neighbouring aquatic bodies due to effluent produced from production plants containing high concentrations of antiviral drugs. Antiviral drugs, such as lamivudine, are extremely bioactive, prompting interest in their urgent removal from the environment. The purpose of the present study was to optimize the removal of lamivudine from the synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. The influence of sorption parameters such as pH, lamivudine concentration, adsorbent dosage, contact time, and calcination temperatures on the removal of lamivudine was investigated and optimized using a response surface methodology (SRM) based on optimal design. The results indicated that, a quadratic model best fits data with a model regression coefficient R2, adjusted R2, and predicted R2 of 0.9934, 0.9761 and 0.8340, respectively. The JS biochar calcined at 750 °C, at pH 8, initial lamivudine concentration of 10 ppm and contact time of 30 min indicated a maximum experimental removal efficiency of 84.9%. The residual standard error (RSE) value was 3.5% implying that the model was reliable. Isotherm data for the adsorption of lamivudine on JS biochar followed the Freundlich isotherm, with an R2 value of 0.9977 while R2 for the modified Langmuir model was 0.9852. These findings indicated that JS biochar is potentially useful for removal of lamivudine, and other organics from contaminated water and wastewater effluents. Therefore, this study presents an environmentally friendly remedy against lamivudine for a healthier ecology.

Validation of a Novel RP-HPLC Technique for Simultaneous Estimation of Lignocaine Hydrochloride and Tibezonium Iodide: Greenness Estimation Using AGREE Penalties.

Herein, we reported an HPLC method for the simultaneous determination of tibezonium iodide (TBN) and lignocaine hydrochloride (LGN). The method was developed according to the International Conference for Harmonization guidelines (ICH) Q2R1 using Agilent® 1260 with a mobile phase consisting of acetonitrile and phosphate buffer (pH 4.5) in a volumetric ratio of 70:30 and flowing through a C8 Agilent® column at 1 mL/min. The results revealed that TBN and LGN peaks were isolated at 4.20 and 2.33 min, respectively, with a resolution of 2.59. The accuracy of TBN and LGN was calculated to be 100.01 ± 1.72% and 99.05 ± 0.65% at 100% concentration, respectively. Similarly, the respective precision was 100.03 ± 1.61% and 99.05 ± 0.48%. The repeatability for TBN and LGN was found to be 99.05 ± 0.48% and 99.19 ± 1.72%, respectively, indicating that the method was precise. The respective regression co-efficient (r2) for TBN and LGN was found to be 0.9995 and 0.9992. Moreover, the LOD and LOQ values for TBN were 0.012 and 0.037 µg/mL, respectively, while for LGN, they were 0.115 and 0.384 µg/mL, respectively. The calculated greenness of the method for ecological safety was found to be 0.83, depicting a green contour on the AGREE scale. No interfering peaks were found when the analyte was estimated in dosage form and in volunteers' saliva, depicting the specificity of the method. Conclusively, a robust, fast, accurate, precise and specific method was successfully validated to estimate TBN and LGN.

Development and validation of a modified QuEChERS method coupled with LC-MS/MS for simultaneous determination of difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole in brinjal collected from fields and markets places to assess human health risk

An effective and sensitive analytical method was developed to quantify the most common pesticide residues (difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole) used for brinjal cultivation in Bangladesh. The quantification of the analytes was done using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using a modified QuEChERS method and followed by purification with dispersive solid phase extraction (d-SPE) sorbents (PSA, GCB, and C18). Matrix-matched calibration with a regression coefficient R2 ≥ 0.9964 were used to minimize the brinjal matrix effect. The method was validated in quintuple (n = 5) at five different spiked levels (8–400 μg/kg) having recoveries in the range of 70.3–113.2% with relative standard deviations RSDs ≤6.8%, limits of detection (LOD) and limits of quantification (LOQ) was in the range of 0.15–0.66 μg/kg and 0.4–2.0 μg/kg, respectively, for the four analytes. A total 100 samples (50 samples directly from fields of Jessore district, Bangladesh and 50 samples from local market of Dhaka, Bangladesh) were collected to analyse the pesticides residue. The result showed that pesticides residue was found in both the field and market collected samples, 54% and 38%, respectively. The overall mean residue levels of four pesticides in field samples were significantly higher than those of market samples. Moreover, 20% of the field samples and 10% of the market samples had dimethoate residues, which were the most abundant among the four analytes and it ranged from 0.017 to 0.252 mg/kg. In terms of health risk assessments, dimethoate showed the highest estimated daily intake (EDI) and hazard quotient (HQ) values that are 3.02 × 10−5 mg/kg/day and 1.51%, respectively, in field samples. Till now, there have been no regulations or guidelines for the maximum admissible pesticide residue in Bangladesh. Therefore, the above findings will be an initial step for the regulatory authorities of Bangladesh to implement regulations and guidelines for pesticide usage.

A Simple, Precise, and Sensitive RP-HPLC Method for Quantification of Teneligliptin Hydrobromide and Metformin Hydrochloride: Development and Validation

Simple, rapid, sensitive, robust, and validated reverse phase- high-performance liquid chromatography RP_(HPLC) was developed for the quantification of anti-diabetic drugs Teneligliptin hydrobromide (TH) and Metformin hydrochloride (MH) in bulk and in formulation. The RP-HPLC method was developed using an HPLC system with a PDA detector. A simple, accurate and cost-effective gradient approach is used by using C18 Inertsil ODS (150×4.6)mm, 5µ. A method was developed and validated as per ICH Q2 (R1) guideline. The efficient separation of both drugs was achieved using an optimised solvent mixture of Buffer: ACN (85:15% v/v) and Methanol: ACN (50:50% v/v) used as a gradient mobile phase, during this experiments flow rate was maintained 0.8 ml/min and at the end the detection of peak carried out by PDA detector at wavelength 249nm. The method has been validated for TH and MH for a range of 16-64μg/ml and 400 - 1600μg/ml with regression coefficient (r2) was 1 and 0.9979 respectively. The optimal approach has been validated in accordance with ICH guideline Q2(R1). The results demonstrated that the method’s accuracy (99.89–100.34 percent w/w and 99.91–100.01 percent w / w TH and MH, respectively) and method is precise as percentage of relative standard deviation <2.0. The proposed LC method used as qualitative as well as quantitative applications for simultaneous quantification of Teneligliptin hydrobromide and Metformin hydrochloride in bulk and tablet dosage form and also sufficient to apply regulatory purpose.

Validated high-performance thin-layer chromatographic method for quantification of gallic acid and ellagic acid in fruits of Terminalia chebula, Phyllanthus emblica, and Quercus infectoria.

A simple and rapid high-performance thin-layer chromatographic method for quantification of gallic acid and ellagic acid in dried fruits of Terminalia chebula, Phyllanthus emblica, and Quercus infectoria has been developed. The chromatographic development was carried out on precoated silica gel 60 F254 plates in a mixture of toluene:ethyl acetate:chloroform:formic acid (4:8:1:3 v/v/v/v). The plate was scanned densitometrically at a wavelength of 280nm. The retention factor value of gallic acid and ellagic acid was found to be 0.63±0.2 and 0.53±0.1, respectively. The developed method was validated in terms of linearity, precision, accuracy, sensitivity, robustness, specificity and stability as per the international conference of harmonization guidelines. The method showed good linear relationship over a range of 100-600ng/band (gallic acid) and 100-500ng/band (ellagic acid) with a regression coefficient (r2 ) of 0.997 (gallic acid) and 0.996 (ellagic acid). The method showed high accuracy (99.65%-100.85%). The percentage relative standard deviation of intra-day and inter-day precision studies was not more than 2%. The method is highly robust and has displayed high specificity. The developed method is new, simple, and accurate and can be successfully employed in routine analysis of raw materials and formulations containing gallic acid and ellagic acid.

A New Heart-Cutting Method for a Multiplex Quantitative Analysis of Steroid Hormones in Plasma Using 2D-LC/MS/MS Technique.

The aim of the current research was to develop a simple and rapid mass spectrometry-based assay for the determination of 15 steroid hormones in human plasma in a single run, which would be suitable for a routine practice setting. For this purpose, we designed a procedure based on the 2D-liquid chromatography-tandem mass spectrometry with a minimalistic sample pre-treatment. In our arrangement, the preparation of one sample takes only 10 min and can accommodate 40 samples per hour when tested in series. The following analytical run is 18 min long for all steroid hormones. In addition, we developed an independent analytical run for estradiol, significantly increasing the assay accuracy while taking an additional 10 min to perform an analytical run of a sample. The optimized method was applied to a set of human plasma samples, including chylous. Our results indicate the linearity of the method for all steroid hormones with squared regression coefficients R2 ≥ 0.995, within-run and between-run precision (RSD < 6.4%), and an accuracy of 92.9% to 106.2%. The absolute recovery for each analyzed steroid hormone ranged between 101.6% and 116.5%. The method detection limit for 15 steroid hormones ranged between 0.008 nmol/L (2.88 pg/mL) for aldosterone and 0.873 nmol/L (0.252 ng/mL) for DHEA. For all the analytes, the lowest calibration point relative standard deviation was less than 10.8%, indicating a good precision of the assay within the lowest concentration of interest. In conclusion, in this method article, we describe a simple, sensitive, and cost-effective 2D-LC/MS/MS method suitable for the routine analysis of a complex of steroid hormones allowing high analytical specificity and sensitivity despite minimal sample processing and short throughput times.

Immunosuppressant Monitoring - Performance of the First Mass Spectrometry-Based Automated Clinical Analyzer Cascadion.

Automatic analyzers simplify processes and may help improve standardization. The first automated analyzer based on mass spectrometry is available and offers a panel for monitoring cyclosporin A, tacrolimus, sirolimus, and everolimus. Method comparisons and evaluation tests are presented to verify the capability of the Cascadion system for use in a clinical laboratory. Sample preparation and measurements were performed using the Cascadion clinical analyzer. More than 1000 measurement values of patient samples were compared with an in vitro diagnostic (IVD)-certified assay run on a liquid chromatography tandem mass spectrometry (LC-MS/MS) instrument. Precision and accuracy were determined using commercial quality control and external quality assessment (EQA) samples. A good correlation between the two instruments was observed (Pearson's correlation r = 0.956-0.996). Deming regression revealed 95% confidence intervals of slopes and intercepts covering the values 1 and 0, for sirolimus and everolimus, respectively, indicating equivalence of both measuring systems. However, for cyclosporin A, a bias was observed and confirmed using a Bland-Altman plot (-9.1%). Measurement repeatability and intermediate measurement precision were appropriate showing coefficients of variation of 0.9-6.1% and 2.0-5.3%, respectively. Accuracy according to internal quality controls was 85-111% and 81-100% in the EQA samples of RfB (Reference Institute of Bioanalytics) and LGC (Laboratory of the Government Chemist), respectively. High robustness was found with regard to the linearity of the calibration lines (linear regression coefficient r2 > 0.99). Carry-over was negligible (0.1%). The Cascadion automatic analyzer produced convincing results in the measurement of patient, control, and EQA samples. The throughput was sufficient for routine use. Overall, it can be used as an alternative to open LC-MS/MS instruments for immunosuppressant monitoring, simplifying processes without the need for specially trained personnel.

Estimation of uniaxial compressive and indirect tensile strengths of intact rock from Schmidt hammer rebound number

Abstract A number of destructive and non-destructive tests were conducted on rock samples collected from various zones in northern Iraq. So far, for Iraqi rocks, few studies have correlated Schmidt hammer rebound (R) with both unconfined compressive strength (UCS) and Brazilian tensile strength (BTS). In this study, the objective is to develop a relationship between the rebound number of Schmidt hammer surface hardness (rebound number) and both the BTS and the unconfined compressive strength (UCS) of different types of northern Iraqi rocks. The required relationship should be based on measured values of the UCS, BT, and Schmidt hammer hardness. To determine the relationship between R and both the UCS and BTS, 120 intact rock samples were prepared and tested using a uniaxial compressive test machine, a Brazilian test apparatus, and an L-type Schmidt hammer test (BTS). Three different types of rock samples (sandstone, claystone, and limestone) were collected from several locations in northern Iraq (Domeez, Baadra, and Zawita). For the three types of rocks, a new linear correlation with a high value of the regression coefficient R 2 is presented, linking the UCS and BTS separately versus R. For the three types of rocks studied, the correlation between UCS and R is better than the correlation between Brazilian tensile strength (BTS) and R.

Quantitative determination of the content of venlafaxine and its active metabolite in human plasma using liquid chromatography-mass spectrometry

A validated method for the quantitative determination of venlafaxine, O-desmethylvenlafaxine in human plasma by tandem liquid chromatographymass spectrometry (HPLC/MS/MS) has been proposed. Sample preparation was carried out by liquid-phase extraction with support (SLE, from «supported liquid extraction») using HyperSEP cartridges and washing with 3-methylbutyl ether. The measure of the target analytes was carried on a triple quadrupole mass spectrometer under multiple-reaction monitoring (+MRM) mode with the electrospray ionization. The calibration curves were linear with regression coefficient r2 &gt; 0.999. The method validation was showed high sensitivity, specificity, accuracy and reproducibility, as well as stability of analytes after freeze/thaw cycles and storage at –20 °C. The method is developed for using in therapeutic drug monitoring.

A Simple and Sensitive LC-MS/MS for Quantitation of ICG in Rat Plasma: Application to a Pre-Clinical Pharmacokinetic Study

A selective, sensitive, and rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitation of ICG in rat plasma. The chromatographic separation was achieved using an ACE excel C18 (3 µm, 50 × 3.0 mm) column, with a mobile phase composition of 0.1% formic acid and 0.1% formic acid in acetonitrile, using a gradient flow at a rate of 0.3 mL/min. The MS was operated at a unit resolution in the multiple reaction monitoring mode, using the precursor ion → product ion combinations of 753.3 → 330.2 m/z (ICG) and 747.45 → 717.50 (Cy7.5 amine) with a run time of 5 min. The assay was linear over a concentration range of 1–1000 ng/mL with a regression coefficient (r2) of 0.998 or better. The inter and intra-batch precision (% relative standard deviation, %RSD) was lower than 13.5%, with accuracy (%Bias) between −10.03% and 11.56%. The ICG was stable under laboratory storage and handling conditions. The validated method was successfully applied to preclinical pharmacokinetic (PK) studies of ICG at a dose of 0.39 mg/kg in rats. PK parameters suggested the highest plasma concentration within 2 min of intravenous dosing with restricted systemic distribution and rapid clearance.

Use of response surface methodology approach for development of sustainable Jojoba biodiesel diesel blend with CuO nanoparticles for four stroke diesel engine

This study focuses primarily on the optimization of performance parameters, namely Brake thermal efficiency (BTE), Brake power (BP) and emission characteristics, namely Hydrocarbon (HC), carbon monoxide (CO) and oxides of nitrogen (NOX) emissions of a diesel engine fuelled with jojoba biodiesel-diesel blend with copper oxide (CuO) nanoparticles dispersed into it with different concentrations of 25, 50, 75 and 100 ppm. Variables such as blend (%), nanoparticles concentration (ppm), fuel injection pressure (bar) and Load (kg) are considered as input parameters. A series of experiments are designed under the central composite rotatable design (CCRD) approach considering 4 input factors each with 5 levels. A nonlinear RSM model is developed between the response and input variables based on the interaction plots. The model is validated by regression coefficient of R2, Adj. R2and Pred. R2which shows satisfactory results.Based on the desirability approach the model retrieve the best combination of input factors as 7.45 kg engine load, 16.76 % mixing of jojoba biodiesel with diesel, 209.89 bar fuel injection pressure, and CuO nanoparticles concentration of 76.76 ppm. After RSM optimization, target values of engine responses (BTE, BP, CO, HC, and NOx) are 27.18 %, 2.5582 kW, 0.1981 % volume, 24.5720 ppm, and 710.9470 ppm, respectively. When the results of the optimization process were compared to the experimental results, the deviations were found to be within the acceptable range of errors which establish the robustness of RSM model.

Method Development And Validation Of Ubrogepant In Bulk And Pharmaceutical Dosage Form By Using Rp-Hplc

The current investigation was pointed at developing and progressively validating novel, simple, responsive and stable RP-HPLC method for the measurement of active pharmaceutical ingredients of Ubrogepant and their related substances. A simple, selective, validated and well-defined stability that shows gradient RP-HPLC methodology for the quantitative determination of Ubrogepant. The chromatographic strategy utilized Column of Dikma Diamsil (4.6 x 150mm, 3mm), using isocratic elution with a mobile phase of 0.1 percent orthophosphoric acid and Acetonitrile (70:30). A flow rate of 1 ml/min and a detector wavelength of 283 nm utilizing the 2487 Uv detector was given in the instrumental settings. Using the impurity-spiked solution, the chromatographic approach was streamlined. Validation of the proposed method was carried out according to an international conference on harmonization (ICH) guidelines. LOD and LOQ for the two active ingredients and their impurities were established with respect to test concentration. The calibration charts plotted were linear with a regression coefficient of R2=0.999, which means the linearity was within the limit. Recovery, specificity, linearity, accuracy, robustness, ruggedness was determined as a part of method validation and the results were found to be within the acceptable range. The proposed method to be fast, simple, feasible and affordable in RS condition. During stability tests, it can be used for routine analysis of production samples and to verify the quality of drug samples during stability studies.

COMPARING THE MOLECULAR PROPERTIES OF ENVIRONMENTAL HORMONES WITH HEARTBEAT CHANGES IN DAPHNIA MAGNA

Rationale: Environmental hormones (EH) disrupt the integrity of the endocrine system. Many chemical compounds act as endocrine disruptors, such as insecticides, herbicides, plasticizers. If these chemical compounds spread outside their area of intended use, they can stay in the environment and flow down into local bodies of water and wreak havoc upon ecosystems in the area. So, understanding the underlying relationship of the EHs with the physiology of an organism may be important for the design of chemical structures that could minimize the adverse effects for the future compounds.&#x0D; Methods: For this study, we chose 10 environmental hormones of BFR, DMT, LCH, DMA, TTS, MLT, ANN, CFT, GPS and GCH to examine the acute cardiac effects for 30 minute incubation in 1:10 serial dilution solutions. The heartbeat rates and their differences were evaluated at pre- and post-incubation, which was then converted into their heartbeat change% based on the pre-heartbeat rates. Then, the heartbeat change % for the individual EH was put on a regression analysis with molecular properties such as molecular weight, XlogP, topological polar surface area (TPSA), complexity, solubility and heavy atom count.&#x0D; Results: The leading coefficient of polynomial function showed relationship with those molecular properties with regression coefficient R2 from 0.1163 to 0.3182. The study should be significantly recognized in that the relationship of acute cardiac effects to the molecular properties were able to quantify as a unique attempt to elucidate. More study might be needed for in-depth clarification in the constants of the polynomial relationship.

Development of QuEChERS clean-up based on EMR-lipid for simultaneous analysis of 9 mycotoxins, acaylamide and 5-Hydroxymethylfurfural in biscuit by UHPLC-MS/MS

A robust and sensitive analytical method for the simultaneous determination of 9 mycotoxins, AA, and 5-HMF by UHPLC-MS/MS was developed. Clean-up of the extracts was achieved by d-SPE with EMR-lipid. A new column phase (C18-PFP) was selected for HPLC separation after comparison with the C18 column. Finally, the method gave good linear relations with regression coefficients R2 > 0.99. The recovery of all the tested compounds was within the range of 70.67 to 104.88%, and the intraday and interday relative standard deviations (RSD) were lower than 12.49. The proposed method was then applied to investigate the mycotoxins, AA and 5-HMF in 20 food samples sold in the retail market. AA and 5-HMF were widely detected, and half of the samples were found to contain at least one mycotoxin contamination. Therefore, this method is potential to be used as a convenient and effective method for the cookies product quality control in the future.

Related Substances Method Development and Validation of Axitinib, Zanubrutinib and Upadacitinib Using RP-HPLC and its Degradation Products were Characterized by Using LC-MS/MS

Background: Axitinib was used to treat carcinoma of renal cells and Upadacitinib was used to treat rheumatoid arthritis and Zanubrutinib used as an anti cancer medication for mantle cell lymphoma. In the current application, Zanubrutinib, Upadacitinib and Axitinib and their associated substances will be developed and validated. Materials and Methods: The optimised method includes the Zanubrutinib, Upadacitinib and Axitinib gradient elution and associated flow rates with dimensions of 1 mL/min and phenyl column X-bridge (150 x 4.6 mm, 3.5 μ). A mobile phase was employed with 1.2 g of Hexane sulphonic acid of pH-2.5 adjusted with ortho-phosphoric acid (buffer) and acetonitrile. Zanubrutinib, Upadacitinib and Axitinib were separated from their associated substances for a total run time of 60 min. The approach developed has been validated in accordance with the ICH guidelines. Results: The test concentration LOD and LOQ were established for both drugs and for their impurities. The diagrams that were drawn were straightforward with an R2 regression coefficient &gt; 0.999. As part of the method validation, recovery, specificity, linearity, accuracy, robustness was determined and the results were found to be within an acceptable range. Conclusion: HPLC was used to validate the method in terms of accuracy, linearity, method precision, accuracy, limit of detection, limit of quantification, robustness, and degradation, and LC-MS/MS was used to characterise the degradation products. The system was validated in all of these aspects.