Contact binaries at various stages of evolution unveil various operating mechanisms that drive them.We report the photometric and period variation analysis of two contact binaries EV Cnc and AH Cnc in open cluster M67...Contact binaries at various stages of evolution unveil various operating mechanisms that drive them.We report the photometric and period variation analysis of two contact binaries EV Cnc and AH Cnc in open cluster M67.We observed the cluster from the JCBT 1.3 m telescope and utilized TESS and Kepler observations.The photometric solutions of EV Cnc and AH Cnc revealed a mass ratio of q~0.41 and~0.15 with an inclination of i=42°and87°respectively.These solutions suggest that EV Cnc is probably a semi-detached and AH Cnc is a deep low-mass ratio contact binary.The study of O-C variation analysis indicates that for both systems,the period is increasing which suggests the mass transfer is occurring from secondary to primary.In the case of AH Cnc and based on simulations by randomly varying the time of minima to fit the LITE solution,we noted the third body orbital period to be around P_(3)=26.82±2.54 yr,which is different from earlier reported values and conclude that future observations are required to confirm this scenario.We compare these two systems with other similar contact binaries to get an estimate of the final configuration of the respective systems.展开更多
The mineralogical and geochemical characteristics of the K-rich granites from the Armoor granitic rocks in the northeastern portion of the Eastern Dharwar Craton(EDC) are presented.In order to understand its physicoch...The mineralogical and geochemical characteristics of the K-rich granites from the Armoor granitic rocks in the northeastern portion of the Eastern Dharwar Craton(EDC) are presented.In order to understand its physicochemical conditions,the petrogenesis of the granitoid was explained from biotite chemistry and geochemical systematics.Studies of mineral chemistry expose that compositionally,K-feldspar and plagioclase in Armoor granite rocks range from An0,Ab_(3-5.9),Or_(94-96.9) and An_(5-29,-Ab71.9-94.9),Or_(0-1.5),respectively.The mineral chemistry of biotite crystals exhibits composition that varies from primary to re-equilibrated primary biotites.Although biotites from the Armoor granites generally exhibit an I-type trend,with calc-alkaline parental magma in a subduction setting.Biotite chemistry of granites displays magnetite(oxidized)series nature,which has oxygen fugacity(fO_(2))=-15.1 to-16.7(log_(10) bar),under high oxidizing conditions.Temperature and pressure estimates for the crystallization of Armoor granites based on biotite composition are T=612-716 ℃ and 1.0-0.4 kbar,respectively.Geochemically,these rocks are metaluminous to slightly peraluminous and magnesian,with calc-alkaline potassiumrich granite.On the chondrite normalized REE diagram,the granites have positive europium anomalies;rich Sr/Y,(Dy/Yb)_(N) ratios and reduced Mg#,Rb/Sr,Rb,Sr indicate that the melting of earlier rocks,crystal accumulation and residual garnet source formed at high pressures.The examined granites show that they are produced from the melting of crustal sources.Thus,the extensive analyses of the described Armoor granite suggest that they were produced by crust sources and developed under oxidizing conditions in subduction setting.展开更多
Dysregulation of post-transcriptional regulation of gene expression has been found to influence various human disorders. Aberrant miRNA-based regulation of gene expression has been found to be associated with differen...Dysregulation of post-transcriptional regulation of gene expression has been found to influence various human disorders. Aberrant miRNA-based regulation of gene expression has been found to be associated with different cancers, including breast cancers. Very little information is available on the effect of dysregulation of miRNA-mediated regulation on luminal B breast cancer. This study was aimed at comprehending the regulation of gene expression through miRNA in luminal B breast cancers by comprehensive analysis of miRNA and mRNA expression data together. Negatively regulated miRNA-target gene pairs were identified, and the target genes were functionally enriched to identify critical pathways associated with luminal B breast cancer. Further, the prognostic significance of these miRNAs and target gene pairs was assessed to identify genes with prognostic value in luminal B breast cancer. A total of 266 differentially expressed miRNAs and 164 dysregulated miRNA-target gene pairs were identified. Four genes, including SRP9, DSN1, RACGAP1, and SLC10A6, and one miRNA, hsa-mir-421, showed significant influence on the prognosis of patients with luminal B breast cancer. Through additional experimental examination of these findings, a deeper comprehension of miRNA-based post-transcriptional regulation in luminal B breast tumors will be possible.展开更多
A novel, simple, and sensitive Ultra Performance Liquid Chromatography (UPLC) method was developed and validated for the quantification of process-related impurities and degradants, as well as the assay of Docetaxel. ...A novel, simple, and sensitive Ultra Performance Liquid Chromatography (UPLC) method was developed and validated for the quantification of process-related impurities and degradants, as well as the assay of Docetaxel. The stability-indicating capability of the method was demonstrated through forced degradation studies and a comprehensive mass balance evaluation. Chromatographic separation was achieved using an ACQUITY UPLC BEH C18 column (100 × 2.1 mm, 1.7 µm), with gradient elution. The mobile phase A comprised a mixture of water, methanol, and acetonitrile (500:300:200, v/v/v), while mobile phase B was acetonitrile and water (800:200, v/v). The flow rate was set at 0.4 mL/min, with detection at 232 nm using a photodiode array detector. The method exhibited excellent performance, with a tailing factor of 1.10 for Docetaxel. The method was rigorously validated for precision, accuracy, linearity, LOD, LOQ, ruggedness, specificity, and robustness. Forced degradation studies confirmed the method’s suitability for stability analysis. Stability testing on the drug substance was conducted following ICH guidelines.展开更多
A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chloride...A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.展开更多
Chronic pancreatitis (CP) is a progressive inflammatory disorder of the pancreas. It is predominantly idiopathic (with an unknown cause) in India and mostly due to alcohol in the West. Diabetes that occur secondary to...Chronic pancreatitis (CP) is a progressive inflammatory disorder of the pancreas. It is predominantly idiopathic (with an unknown cause) in India and mostly due to alcohol in the West. Diabetes that occur secondary to chronic pancreatitis (T3c Diabetes) is often brittle, and is difficult to attain normoglycemia with conventional treatment requiring multiple doses of insulin. Mild and severe model of CP was induced in mice by repeated intraperitoneal injections of cerulein and L-arginine respectively with an intent to study islet dysfunction and develop therapeutic strategy in animal models of CP. Dietary intervention of epigallocatechin-3-gallate (EGCG) was tested in both the models of CP for its beneficial effects on insulin secretory functions. Pancreata collected upon euthanasia were used to study alterations in the morphology of pancreatic parenchyma and inflammation by staining with H&E and fibrotic changes by Masson’s trichrome and picrosirius staining. Insulin secretory functions of islets were evaluated to test the efficacy of the dietary intervention on β-cell functions. Intraperitoneal glucose tolerance test was performed to monitor the glucose homeostasis before and after the dietary intervention. Both the models resulted in CP with dispersed acini, inflammation and fibrosis. The loss of acini and extent of fibrosis was more in L-arginine model. 2-fold improvement in glucose-stimulated insulin secretory functions of islets was observed with 0.5% EGCG dietary intervention in cerulein model of CP and 1.6-fold in L-arginine model of CP. A further improvement in insulin secretion by 3.2-fold was observed with additional dietary supplements like N-acetyl cysteine, curcumin in combination with EGCG. Our results thus demonstrate and highlight the therapeutic potential of dietary green tea (EGCG) supplementation in reversing islet dysfunction and improving glucose homeostasis in experimental chronic pancreatitis in mice.展开更多
Magma produced by melting of continental crust and mantle at the Archean-Proterozoic boundary are compositionally variable and chemical compositions provide evidence for the mixing of two sources. Understanding the co...Magma produced by melting of continental crust and mantle at the Archean-Proterozoic boundary are compositionally variable and chemical compositions provide evidence for the mixing of two sources. Understanding the composition of hybrid magma is essential for determining the comparative infl uence of crust and mantle sources during orogenesis. The hybrid granites are less documented in Indian cratons, especially less in Dharwar Craton. Here we present petrographic and whole-rock geochemical data of Madgulapalli granitic rocks situated in the NE part of the Eastern Dharwar Craton(EDC), to elucidate their petrogenesis and role in crust formation. The Madugulapalli granites(MPG) are composed chiefl y of plagioclase, quartz, and alkali feldspar with associated biotite showing alteration and inter-granular textures. Geochemically, they are metaluminous to peraluminous in nature with calc-alkaline hybrid granite. The hybrid granites exhibit both negative and positive europium anomalies;the lower Rb/Sr, Rb, Sr, and higher Sr/Y,(Dy/Yb)N ratios suggest that the interaction of older rocks with residual garnet source melted at high pressures. We hypothesize that hybrid granites are formed by interaction(e.g., metasomatism, mingling, or mixing) between parental magmas and pre-existing rocks with the infl uence of sanukitoid melts(heat source) in a subduction environment. The genesis of the hybrid granites demonstrates the mixing coupled with diff erentiation in the petrogeny’s residue system in a syn-collision setting followed by continental crust stability in EDC during the Neoarchean period.展开更多
The first photometric,spectroscopic and period variation studies of neglected short-period eclipsing binary V2840Cygni are presented.High mass ratio contact binaries(HMRCBs),especially those in the weak-contact config...The first photometric,spectroscopic and period variation studies of neglected short-period eclipsing binary V2840Cygni are presented.High mass ratio contact binaries(HMRCBs),especially those in the weak-contact configuration,are vital when probing the evolutionary models of contact binaries(CBs) using stellar parameters.The photometric solutions reveal the weak-contact nature of V2840 Cygni with a high mass ratio(~1.36),motivating us to investigate the nature of such binaries.The period variation study of V2840 Cygni spanning 15 yr shows a secular period decrease at a rate of ~5.5 × 10^(-7) day yr^(-1),indicating mass transfer between the components.The superimposed cyclic variation provides a basic understanding of the possible third body(P_(3)- 8 yr,m_(3)- 0.51 M_(⊙)).Following the derived parameters,the evolution of the system is discussed based on the thermal relaxation oscillation(TRO) model.It is found that V2840 Cygni falls in a special category of HMRCBs,which validates TRO.To characterize the nature of HMRCBs,a catalog of 59 CBs with high mass ratios has been compiled along with their derived parameters from the literature.For all the HMRCBs in the study,a possible correlation between their contact configuration and observed period variations for relative log J_(rel) is discussed.The spectroscopic study of V2840 Cygni provides evidence of the presence of magnetic activity in the system and the existence of ongoing mass transfer which is additionally deduced from the period variation study.The LAMOST spectra of 17 HMRCBs are collected to interpret the stellar magnetic activity in such systems.展开更多
Marginal short-period contact binaries are important to understand as they pose a different physical scenario than the predicted theoretical model based on the thermal relaxation oscillation mechanism due to their sha...Marginal short-period contact binaries are important to understand as they pose a different physical scenario than the predicted theoretical model based on the thermal relaxation oscillation mechanism due to their shallow degree of contact.Here we present the optical and X-ray studies of a contact binary source RW Dor using the Transiting Exoplanet Survey Satellite(TESS)and XMM-Newton telescopes.For the first time we report the varying O'Connell effect and explain the asymmetry with a spot model.Based on the new times of minima,we make a robust estimate of the orbital period of the third body at 47.01~0.52 yr with an eccentricity e=0.21.We show that the period-decreasing trend observed in O-C variation can be explained by both conservative mass transfer from primary to secondary and AML via stellar wind.The X-ray luminosity exhibited by RW Dor did not vary significantly on three different occasions and was found to be about 3.34×10~(29)erg s~(-1).Assuming that the quiescent X-ray emission is emitted from an undisturbed loop structure,the loop size is estimated to be 0.6-1×10~(10)cm which is≤Alfvén radius r_A~8×10~(10)cm.展开更多
Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,an...Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,and contractors,completing building projects within the specified cost budget has become the most important and hard assignment.Since it is common for high-rise building projects to go over budget,the aim of this study is to find out the causes of cost overruns and provide effective measures.The study found 70 cost overrun factors based on a comprehensive literature review and expert opinions.A Google form questionnaire was distributed to 150 construction professionals across India.After following up,101 of the 150 responses were received.A five-point Likert scale was used and the acquired data was analyzed and ranked using the Relative Importance Index(RII)technique.According to the findings of RII,the top ten critical factors influencing cost overruns were frequent change orders during construction by the owner,delay in construction,escalation of material prices,market inflation or deflation,rework,frequent changes in design,inaccurate evaluation of the project timeline,unforeseen ground condition,inaccurate quantity take-off,and delay in progressive payment by the owner.Spearman’s rank correlation test revealed that there is a very significant relationship between the rankings of factors provided by the owner,the consultant,and the contractor.In addition,a factor analysis tool in the SPSS software was also used to categorize the seventy factors into sixteen core components.The top ten critical factors were presented to subject matter experts,and their suggestions were being compiled.These results are expected to help construction professionals minimize cost overruns,improve cost control measures,and initiate future research.展开更多
Marginal contact binary systems are an important class of binary systems in exploited by astronomers to understand various astrophysical phenomena as they bridge both semi-detached and overcontact stages.We studied th...Marginal contact binary systems are an important class of binary systems in exploited by astronomers to understand various astrophysical phenomena as they bridge both semi-detached and overcontact stages.We studied the photometric data of CW Aqr using the JCB 1.3 m telescope(JCBT),Kepler,and TESS to understand the period variations and constrain the light curve solutions.We noted that the period of CW Aqr is increasing with a mass transfer rate of m=7.53×10^(-8)M_(⊙)yr^(-1)from the secondary to the primary component.We also ascertained cyclic deviations along with a parabolic trend in the O-C diagram.The residuals displayed a sinusoidal trend which was fitted with an LTTE,indicating the presence of a third body with an orbital period of P_(3)~10 yr and e=0.10.We fitted the JCBT,Kepler,and TESS photometric normalized light curves and noted the mass ratio to be q~0.32 for both contact and semi-detached configurations.We identified a temperature difference between the primary and secondary components of~2500 K.No activity signatures were found in the observed light curves which were also evident from the Hαline studies where the filled-in effect was not seen.Overall our study suggests that CW Aqr is a marginal contact binary with a low mass ratio evolving toward a semi-detached configuration.However,it may merge if the period increases due to ongoing mass transfer accompanied by a lowering in the mass ratio and later oscillate back to the period-decreasing trend due to angular momentum loss over a few cycles of thermal relaxation oscillations followed by instability.展开更多
In this paper we explore the formation of bars and present the bulge and bar properties and their correlations for a sample of lenticular barred(SB0)and lenticular unbarred(S0)galaxies in the central region of the Com...In this paper we explore the formation of bars and present the bulge and bar properties and their correlations for a sample of lenticular barred(SB0)and lenticular unbarred(S0)galaxies in the central region of the Coma Cluster using HST/ACS data.In our sample,we identified bar features using the luminosity profile decomposition software GALFIT.We classified the bulges based on Sérsic index and Kormendy relation.We found that the average mass of the bulge in SB0 galaxies is 1.48×10^(10)M☉whereas the average mass of the bulge in S0 galaxies is 4.3×10^(10)M☉.We observe that SB0 galaxies show lower bulge concentration,low mass and also smaller B/T values compared to S0 galaxies.Using the Kormendy relation,we found that among the lenticular barred galaxies,82%have classical bulges and 18%have pseudo bulges.These classical bulges have low masses compared to the classical bulges of unbarred galaxies.S0,galaxies with massive classical bulges do not host bars.We also found that for all SB0s the bulge effective radius is less than the bar effective radius.SB0 galaxies with classical bulges suggest that the bar may have formed by mergers.展开更多
Sunflower is one of the most used commercial oilseed crops and suffers due to Powdery mildew. RNA sequence alteration occurs due to RNA editing which is a post transcriptional modification. It causes a deviation from ...Sunflower is one of the most used commercial oilseed crops and suffers due to Powdery mildew. RNA sequence alteration occurs due to RNA editing which is a post transcriptional modification. It causes a deviation from the genomic DNA sequence resulting in RNA-DNA differences. Accurate study of RNA editing events in diverse species is possible by NGS based methods. Here, we performed RNA sequencing of 12 leaf transcriptomes, which include three genotypes of Helianthus annuus (2023B, TX16R and ID25), H. debilis, H. niveus, and H. praecox along with their respective powdery mildew pathogen infected variants and systematically analysed the mitochondrial RNA editing events using computational reference-based mapping approach. We discovered 687 editing sites, 220 editing events in the protein-coding regions, among all species and genotypes considered in this study. These included “C to U” and “U to C” RNA editing events. On further analysis, we observed that these editing events include 14 different types of amino acid changes that involve the creation of two stop codon events. The conserved editing sites identified were 247 accounting for ~36% of all the editing sites identified. This study provides a detailed picture of the Helianthus species’ mitochondrial RNA editing status. We have identified and characterized for the first time, genotype-specific, species-specific, and stress-specific RNA editing events which may be useful as a potential source for stress-responsive studies in the future.展开更多
Understanding the variation of lags with respect to the X-ray flux is important to explore the geometry of the inner region of the accretion disk in AGNs.We performed frequency-lag,energy–lag and spectral studies for...Understanding the variation of lags with respect to the X-ray flux is important to explore the geometry of the inner region of the accretion disk in AGNs.We performed frequency-lag,energy–lag and spectral studies for two sets of observations,in order to investigate the variations in lags with respect to X-ray flux in the AGN source Mrk 704 using the XMM-Newton observatory.We divided one of the light curves into two sections which were noticed to exhibit a flux variation.The frequency-lag spectra in different energy domains revealed that reverberation(soft)lags varied along with the flux.For the first time,we show that the blurred reflection model can consistently explain the soft excess observed in the X-ray spectra for this source.The fluxes of soft(i.e.,reflection)and hard components were noted to vary by~18%and~9%respectively,across the sections.The soft lag amplitude was found to be larger at the high flux state than the amplitude at the low flux state.Most importantly,we found that both frequency-lag and energy–lag spectra do not display significant variation between two observational data sets despite a flux variation of 43%.This phenomenon cannot be explained by the reflection model because the soft lag amplitudes must be larger in the high flux state.The probable scenario is that,in the low flux state,the obscuring cloud delays the reflected soft photons which increases the soft lag amplitude.展开更多
AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: Polymerase chain reaction (PCR) amplification using Y-specific STS of azoospermia facto...AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: Polymerase chain reaction (PCR) amplification using Y-specific STS of azoospermia factor (AZF) regions i.e., SY 84 for AZFa, SY 127 for AZFb and SY 254 for AZFc. RESULTS: Of the 20 infertile subjects 3 (15 %), one azoospermic and two oligozoospermic, showed microdeletions in the AZF region of Y-chromosome. CONCLUSION: The frequency of deletions involving AZF region of the Y-chromosome is 15 % in azoospermic and severely oligozoospermic infertile men. PCR amplification of AZF locus is useful for the diagnosis of microdeletions in the Y-chromosome.展开更多
Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 ba...Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 bars of osmotic pressure) was studied. Brassinosteroids supplementation reduced the inhibitory effect of water stress on seed germination and seedling growth. The growth stimulation in radish seedlings by brassinosteroids under desiccation stress was associated with elevated levels of nucleic acids and soluble proteins and lowered activities of RNase. The mitigation of osmotic stress imposed by PEG was associated with increased scavenging of reactive oxygen species as reflected in elevated activities of superoxide dismutase, catalase and ascorbate peroxidase. Brassinosteroids also enhanced the accumulation of the osmolyte free proline in radish seedlings challenged with drought stress. The two brassinosteroids also maintained membrane integrity under water deficiency conditions as indicated by lowered lipid peroxidation reflecting in reduced MDA content. The results of present study demonstrate the protective role of brassinosteroids against PEG imposed water stress in radish seedlings.展开更多
The effect of dysprosium and strontium on the total ionic conductivity of ceria in the system Ce1-xDyx-ySryO2-δ was studied. In this system, few compositions were prepared with x=0.15, y=0.015, 0.03 and 0.045 by modi...The effect of dysprosium and strontium on the total ionic conductivity of ceria in the system Ce1-xDyx-ySryO2-δ was studied. In this system, few compositions were prepared with x=0.15, y=0.015, 0.03 and 0.045 by modified sol-gel process using maltose and pectin as organic precursors. Rietveld refinement of XRD patterns confirms the cubic structure with space group Fm3m . SEM images show relatively uniform grains with clean and distinct grain boundaries. Four probe AC impedance measurements were carried out to evaluate the total ionic conductivity in the temperature range of 150-500 ℃ and frequency range of 40 Hz-1 MHz. The composition Ce0.85Dy0.12Sr0.03O2-δshows higher electrical conductivity than single-doped ceria samples.展开更多
A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furo...A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furosemide was used as an internal standard.Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether.The reconstituted samples were chromatographed on a Zorbax SB-C;8 column by using a mixture of 5 mM ammonium acetate buffer and acetonitrile（20:80,v/v） as the mobile phase at a flow rate of 0.8 mL/min.The calibration curve obtained was linear（r≥0.99） over the concentration range of 0.50-600.29 ng/mL for pravastatin and 20.07-2012.00 ng/mL for aspirin.Method validation was performed as per FDA guidelines and the results met the acceptance criteria.A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day.The proposed method was found to be applicable to clinical studies.展开更多
Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good effic...Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.展开更多
A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric （LC MS/ MS） assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and g.）im...A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric （LC MS/ MS） assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and g.）imepiride in human plasma. Carbamazepine was used as internal standard （IS）. The analytes were extracted from 200 μL aliquots of human plasma via protein precipitation using acetonitrile, The reconstituted samples were chromatographed on a Alltima HP C18 column by using a 60：40 （v/v） mixture of acetonitrile and 10 mM ammonium acetate （pH 3.0） as the mobile phase at a flow rate of 1.1 mL/min. The calibration curves obtained were linear （r2〉0.99） over the concentration range of 0.50-150.03 ng/mL for atorvastatin, 12.14-1207.50 ng/mL for metformin and 4.98-494.29 ng/mL for glimepiride. The API-4000 LC-MS/MS in multiple reaction monitoring （MRM） mode was used for detection. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. All the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 rain for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers.展开更多
基金support from the SRF INSPIRE(IF 170314)fellowship program,Government of Indiafinancial support from the SERB Core Research Grant project,the Government of India。
文摘Contact binaries at various stages of evolution unveil various operating mechanisms that drive them.We report the photometric and period variation analysis of two contact binaries EV Cnc and AH Cnc in open cluster M67.We observed the cluster from the JCBT 1.3 m telescope and utilized TESS and Kepler observations.The photometric solutions of EV Cnc and AH Cnc revealed a mass ratio of q~0.41 and~0.15 with an inclination of i=42°and87°respectively.These solutions suggest that EV Cnc is probably a semi-detached and AH Cnc is a deep low-mass ratio contact binary.The study of O-C variation analysis indicates that for both systems,the period is increasing which suggests the mass transfer is occurring from secondary to primary.In the case of AH Cnc and based on simulations by randomly varying the time of minima to fit the LITE solution,we noted the third body orbital period to be around P_(3)=26.82±2.54 yr,which is different from earlier reported values and conclude that future observations are required to confirm this scenario.We compare these two systems with other similar contact binaries to get an estimate of the final configuration of the respective systems.
文摘The mineralogical and geochemical characteristics of the K-rich granites from the Armoor granitic rocks in the northeastern portion of the Eastern Dharwar Craton(EDC) are presented.In order to understand its physicochemical conditions,the petrogenesis of the granitoid was explained from biotite chemistry and geochemical systematics.Studies of mineral chemistry expose that compositionally,K-feldspar and plagioclase in Armoor granite rocks range from An0,Ab_(3-5.9),Or_(94-96.9) and An_(5-29,-Ab71.9-94.9),Or_(0-1.5),respectively.The mineral chemistry of biotite crystals exhibits composition that varies from primary to re-equilibrated primary biotites.Although biotites from the Armoor granites generally exhibit an I-type trend,with calc-alkaline parental magma in a subduction setting.Biotite chemistry of granites displays magnetite(oxidized)series nature,which has oxygen fugacity(fO_(2))=-15.1 to-16.7(log_(10) bar),under high oxidizing conditions.Temperature and pressure estimates for the crystallization of Armoor granites based on biotite composition are T=612-716 ℃ and 1.0-0.4 kbar,respectively.Geochemically,these rocks are metaluminous to slightly peraluminous and magnesian,with calc-alkaline potassiumrich granite.On the chondrite normalized REE diagram,the granites have positive europium anomalies;rich Sr/Y,(Dy/Yb)_(N) ratios and reduced Mg#,Rb/Sr,Rb,Sr indicate that the melting of earlier rocks,crystal accumulation and residual garnet source formed at high pressures.The examined granites show that they are produced from the melting of crustal sources.Thus,the extensive analyses of the described Armoor granite suggest that they were produced by crust sources and developed under oxidizing conditions in subduction setting.
文摘Dysregulation of post-transcriptional regulation of gene expression has been found to influence various human disorders. Aberrant miRNA-based regulation of gene expression has been found to be associated with different cancers, including breast cancers. Very little information is available on the effect of dysregulation of miRNA-mediated regulation on luminal B breast cancer. This study was aimed at comprehending the regulation of gene expression through miRNA in luminal B breast cancers by comprehensive analysis of miRNA and mRNA expression data together. Negatively regulated miRNA-target gene pairs were identified, and the target genes were functionally enriched to identify critical pathways associated with luminal B breast cancer. Further, the prognostic significance of these miRNAs and target gene pairs was assessed to identify genes with prognostic value in luminal B breast cancer. A total of 266 differentially expressed miRNAs and 164 dysregulated miRNA-target gene pairs were identified. Four genes, including SRP9, DSN1, RACGAP1, and SLC10A6, and one miRNA, hsa-mir-421, showed significant influence on the prognosis of patients with luminal B breast cancer. Through additional experimental examination of these findings, a deeper comprehension of miRNA-based post-transcriptional regulation in luminal B breast tumors will be possible.
文摘A novel, simple, and sensitive Ultra Performance Liquid Chromatography (UPLC) method was developed and validated for the quantification of process-related impurities and degradants, as well as the assay of Docetaxel. The stability-indicating capability of the method was demonstrated through forced degradation studies and a comprehensive mass balance evaluation. Chromatographic separation was achieved using an ACQUITY UPLC BEH C18 column (100 × 2.1 mm, 1.7 µm), with gradient elution. The mobile phase A comprised a mixture of water, methanol, and acetonitrile (500:300:200, v/v/v), while mobile phase B was acetonitrile and water (800:200, v/v). The flow rate was set at 0.4 mL/min, with detection at 232 nm using a photodiode array detector. The method exhibited excellent performance, with a tailing factor of 1.10 for Docetaxel. The method was rigorously validated for precision, accuracy, linearity, LOD, LOQ, ruggedness, specificity, and robustness. Forced degradation studies confirmed the method’s suitability for stability analysis. Stability testing on the drug substance was conducted following ICH guidelines.
文摘A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.
文摘Chronic pancreatitis (CP) is a progressive inflammatory disorder of the pancreas. It is predominantly idiopathic (with an unknown cause) in India and mostly due to alcohol in the West. Diabetes that occur secondary to chronic pancreatitis (T3c Diabetes) is often brittle, and is difficult to attain normoglycemia with conventional treatment requiring multiple doses of insulin. Mild and severe model of CP was induced in mice by repeated intraperitoneal injections of cerulein and L-arginine respectively with an intent to study islet dysfunction and develop therapeutic strategy in animal models of CP. Dietary intervention of epigallocatechin-3-gallate (EGCG) was tested in both the models of CP for its beneficial effects on insulin secretory functions. Pancreata collected upon euthanasia were used to study alterations in the morphology of pancreatic parenchyma and inflammation by staining with H&E and fibrotic changes by Masson’s trichrome and picrosirius staining. Insulin secretory functions of islets were evaluated to test the efficacy of the dietary intervention on β-cell functions. Intraperitoneal glucose tolerance test was performed to monitor the glucose homeostasis before and after the dietary intervention. Both the models resulted in CP with dispersed acini, inflammation and fibrosis. The loss of acini and extent of fibrosis was more in L-arginine model. 2-fold improvement in glucose-stimulated insulin secretory functions of islets was observed with 0.5% EGCG dietary intervention in cerulein model of CP and 1.6-fold in L-arginine model of CP. A further improvement in insulin secretion by 3.2-fold was observed with additional dietary supplements like N-acetyl cysteine, curcumin in combination with EGCG. Our results thus demonstrate and highlight the therapeutic potential of dietary green tea (EGCG) supplementation in reversing islet dysfunction and improving glucose homeostasis in experimental chronic pancreatitis in mice.
基金the UGC (New Delhi) for awarding RGNF-Research FellowshipsUGC-Emeritus Fellowship (#201718-Eme ritus-10196-1)。
文摘Magma produced by melting of continental crust and mantle at the Archean-Proterozoic boundary are compositionally variable and chemical compositions provide evidence for the mixing of two sources. Understanding the composition of hybrid magma is essential for determining the comparative infl uence of crust and mantle sources during orogenesis. The hybrid granites are less documented in Indian cratons, especially less in Dharwar Craton. Here we present petrographic and whole-rock geochemical data of Madgulapalli granitic rocks situated in the NE part of the Eastern Dharwar Craton(EDC), to elucidate their petrogenesis and role in crust formation. The Madugulapalli granites(MPG) are composed chiefl y of plagioclase, quartz, and alkali feldspar with associated biotite showing alteration and inter-granular textures. Geochemically, they are metaluminous to peraluminous in nature with calc-alkaline hybrid granite. The hybrid granites exhibit both negative and positive europium anomalies;the lower Rb/Sr, Rb, Sr, and higher Sr/Y,(Dy/Yb)N ratios suggest that the interaction of older rocks with residual garnet source melted at high pressures. We hypothesize that hybrid granites are formed by interaction(e.g., metasomatism, mingling, or mixing) between parental magmas and pre-existing rocks with the infl uence of sanukitoid melts(heat source) in a subduction environment. The genesis of the hybrid granites demonstrates the mixing coupled with diff erentiation in the petrogeny’s residue system in a syn-collision setting followed by continental crust stability in EDC during the Neoarchean period.
基金Funding for the project has been provided by the National Development and Reform Commission。
文摘The first photometric,spectroscopic and period variation studies of neglected short-period eclipsing binary V2840Cygni are presented.High mass ratio contact binaries(HMRCBs),especially those in the weak-contact configuration,are vital when probing the evolutionary models of contact binaries(CBs) using stellar parameters.The photometric solutions reveal the weak-contact nature of V2840 Cygni with a high mass ratio(~1.36),motivating us to investigate the nature of such binaries.The period variation study of V2840 Cygni spanning 15 yr shows a secular period decrease at a rate of ~5.5 × 10^(-7) day yr^(-1),indicating mass transfer between the components.The superimposed cyclic variation provides a basic understanding of the possible third body(P_(3)- 8 yr,m_(3)- 0.51 M_(⊙)).Following the derived parameters,the evolution of the system is discussed based on the thermal relaxation oscillation(TRO) model.It is found that V2840 Cygni falls in a special category of HMRCBs,which validates TRO.To characterize the nature of HMRCBs,a catalog of 59 CBs with high mass ratios has been compiled along with their derived parameters from the literature.For all the HMRCBs in the study,a possible correlation between their contact configuration and observed period variations for relative log J_(rel) is discussed.The spectroscopic study of V2840 Cygni provides evidence of the presence of magnetic activity in the system and the existence of ongoing mass transfer which is additionally deduced from the period variation study.The LAMOST spectra of 17 HMRCBs are collected to interpret the stellar magnetic activity in such systems.
基金financial support from the SERB Core Research Grant project,the Government of Indiasupport from the SRF INSPIRE(IF 170314)fellowship program,Government of India。
文摘Marginal short-period contact binaries are important to understand as they pose a different physical scenario than the predicted theoretical model based on the thermal relaxation oscillation mechanism due to their shallow degree of contact.Here we present the optical and X-ray studies of a contact binary source RW Dor using the Transiting Exoplanet Survey Satellite(TESS)and XMM-Newton telescopes.For the first time we report the varying O'Connell effect and explain the asymmetry with a spot model.Based on the new times of minima,we make a robust estimate of the orbital period of the third body at 47.01~0.52 yr with an eccentricity e=0.21.We show that the period-decreasing trend observed in O-C variation can be explained by both conservative mass transfer from primary to secondary and AML via stellar wind.The X-ray luminosity exhibited by RW Dor did not vary significantly on three different occasions and was found to be about 3.34×10~(29)erg s~(-1).Assuming that the quiescent X-ray emission is emitted from an undisturbed loop structure,the loop size is estimated to be 0.6-1×10~(10)cm which is≤Alfvén radius r_A~8×10~(10)cm.
文摘Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,and contractors,completing building projects within the specified cost budget has become the most important and hard assignment.Since it is common for high-rise building projects to go over budget,the aim of this study is to find out the causes of cost overruns and provide effective measures.The study found 70 cost overrun factors based on a comprehensive literature review and expert opinions.A Google form questionnaire was distributed to 150 construction professionals across India.After following up,101 of the 150 responses were received.A five-point Likert scale was used and the acquired data was analyzed and ranked using the Relative Importance Index(RII)technique.According to the findings of RII,the top ten critical factors influencing cost overruns were frequent change orders during construction by the owner,delay in construction,escalation of material prices,market inflation or deflation,rework,frequent changes in design,inaccurate evaluation of the project timeline,unforeseen ground condition,inaccurate quantity take-off,and delay in progressive payment by the owner.Spearman’s rank correlation test revealed that there is a very significant relationship between the rankings of factors provided by the owner,the consultant,and the contractor.In addition,a factor analysis tool in the SPSS software was also used to categorize the seventy factors into sixteen core components.The top ten critical factors were presented to subject matter experts,and their suggestions were being compiled.These results are expected to help construction professionals minimize cost overruns,improve cost control measures,and initiate future research.
基金the Core Research Grant of SERB,India for the financial support。
文摘Marginal contact binary systems are an important class of binary systems in exploited by astronomers to understand various astrophysical phenomena as they bridge both semi-detached and overcontact stages.We studied the photometric data of CW Aqr using the JCB 1.3 m telescope(JCBT),Kepler,and TESS to understand the period variations and constrain the light curve solutions.We noted that the period of CW Aqr is increasing with a mass transfer rate of m=7.53×10^(-8)M_(⊙)yr^(-1)from the secondary to the primary component.We also ascertained cyclic deviations along with a parabolic trend in the O-C diagram.The residuals displayed a sinusoidal trend which was fitted with an LTTE,indicating the presence of a third body with an orbital period of P_(3)~10 yr and e=0.10.We fitted the JCBT,Kepler,and TESS photometric normalized light curves and noted the mass ratio to be q~0.32 for both contact and semi-detached configurations.We identified a temperature difference between the primary and secondary components of~2500 K.No activity signatures were found in the observed light curves which were also evident from the Hαline studies where the filled-in effect was not seen.Overall our study suggests that CW Aqr is a marginal contact binary with a low mass ratio evolving toward a semi-detached configuration.However,it may merge if the period increases due to ongoing mass transfer accompanied by a lowering in the mass ratio and later oscillate back to the period-decreasing trend due to angular momentum loss over a few cycles of thermal relaxation oscillations followed by instability.
文摘In this paper we explore the formation of bars and present the bulge and bar properties and their correlations for a sample of lenticular barred(SB0)and lenticular unbarred(S0)galaxies in the central region of the Coma Cluster using HST/ACS data.In our sample,we identified bar features using the luminosity profile decomposition software GALFIT.We classified the bulges based on Sérsic index and Kormendy relation.We found that the average mass of the bulge in SB0 galaxies is 1.48×10^(10)M☉whereas the average mass of the bulge in S0 galaxies is 4.3×10^(10)M☉.We observe that SB0 galaxies show lower bulge concentration,low mass and also smaller B/T values compared to S0 galaxies.Using the Kormendy relation,we found that among the lenticular barred galaxies,82%have classical bulges and 18%have pseudo bulges.These classical bulges have low masses compared to the classical bulges of unbarred galaxies.S0,galaxies with massive classical bulges do not host bars.We also found that for all SB0s the bulge effective radius is less than the bar effective radius.SB0 galaxies with classical bulges suggest that the bar may have formed by mergers.
文摘Sunflower is one of the most used commercial oilseed crops and suffers due to Powdery mildew. RNA sequence alteration occurs due to RNA editing which is a post transcriptional modification. It causes a deviation from the genomic DNA sequence resulting in RNA-DNA differences. Accurate study of RNA editing events in diverse species is possible by NGS based methods. Here, we performed RNA sequencing of 12 leaf transcriptomes, which include three genotypes of Helianthus annuus (2023B, TX16R and ID25), H. debilis, H. niveus, and H. praecox along with their respective powdery mildew pathogen infected variants and systematically analysed the mitochondrial RNA editing events using computational reference-based mapping approach. We discovered 687 editing sites, 220 editing events in the protein-coding regions, among all species and genotypes considered in this study. These included “C to U” and “U to C” RNA editing events. On further analysis, we observed that these editing events include 14 different types of amino acid changes that involve the creation of two stop codon events. The conserved editing sites identified were 247 accounting for ~36% of all the editing sites identified. This study provides a detailed picture of the Helianthus species’ mitochondrial RNA editing status. We have identified and characterized for the first time, genotype-specific, species-specific, and stress-specific RNA editing events which may be useful as a potential source for stress-responsive studies in the future.
基金K.S.acknowledges the financial support from the Indian Space Research Organisation(ISRO),Government of India。
文摘Understanding the variation of lags with respect to the X-ray flux is important to explore the geometry of the inner region of the accretion disk in AGNs.We performed frequency-lag,energy–lag and spectral studies for two sets of observations,in order to investigate the variations in lags with respect to X-ray flux in the AGN source Mrk 704 using the XMM-Newton observatory.We divided one of the light curves into two sections which were noticed to exhibit a flux variation.The frequency-lag spectra in different energy domains revealed that reverberation(soft)lags varied along with the flux.For the first time,we show that the blurred reflection model can consistently explain the soft excess observed in the X-ray spectra for this source.The fluxes of soft(i.e.,reflection)and hard components were noted to vary by~18%and~9%respectively,across the sections.The soft lag amplitude was found to be larger at the high flux state than the amplitude at the low flux state.Most importantly,we found that both frequency-lag and energy–lag spectra do not display significant variation between two observational data sets despite a flux variation of 43%.This phenomenon cannot be explained by the reflection model because the soft lag amplitudes must be larger in the high flux state.The probable scenario is that,in the low flux state,the obscuring cloud delays the reflected soft photons which increases the soft lag amplitude.
文摘AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: Polymerase chain reaction (PCR) amplification using Y-specific STS of azoospermia factor (AZF) regions i.e., SY 84 for AZFa, SY 127 for AZFb and SY 254 for AZFc. RESULTS: Of the 20 infertile subjects 3 (15 %), one azoospermic and two oligozoospermic, showed microdeletions in the AZF region of Y-chromosome. CONCLUSION: The frequency of deletions involving AZF region of the Y-chromosome is 15 % in azoospermic and severely oligozoospermic infertile men. PCR amplification of AZF locus is useful for the diagnosis of microdeletions in the Y-chromosome.
文摘Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 bars of osmotic pressure) was studied. Brassinosteroids supplementation reduced the inhibitory effect of water stress on seed germination and seedling growth. The growth stimulation in radish seedlings by brassinosteroids under desiccation stress was associated with elevated levels of nucleic acids and soluble proteins and lowered activities of RNase. The mitigation of osmotic stress imposed by PEG was associated with increased scavenging of reactive oxygen species as reflected in elevated activities of superoxide dismutase, catalase and ascorbate peroxidase. Brassinosteroids also enhanced the accumulation of the osmolyte free proline in radish seedlings challenged with drought stress. The two brassinosteroids also maintained membrane integrity under water deficiency conditions as indicated by lowered lipid peroxidation reflecting in reduced MDA content. The results of present study demonstrate the protective role of brassinosteroids against PEG imposed water stress in radish seedlings.
基金the UGC for providing financial assistance under DSKPDF, BSR project No. F.4-2/2006(BSR)/13-389/2010 (BSR)
文摘The effect of dysprosium and strontium on the total ionic conductivity of ceria in the system Ce1-xDyx-ySryO2-δ was studied. In this system, few compositions were prepared with x=0.15, y=0.015, 0.03 and 0.045 by modified sol-gel process using maltose and pectin as organic precursors. Rietveld refinement of XRD patterns confirms the cubic structure with space group Fm3m . SEM images show relatively uniform grains with clean and distinct grain boundaries. Four probe AC impedance measurements were carried out to evaluate the total ionic conductivity in the temperature range of 150-500 ℃ and frequency range of 40 Hz-1 MHz. The composition Ce0.85Dy0.12Sr0.03O2-δshows higher electrical conductivity than single-doped ceria samples.
文摘A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furosemide was used as an internal standard.Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether.The reconstituted samples were chromatographed on a Zorbax SB-C;8 column by using a mixture of 5 mM ammonium acetate buffer and acetonitrile（20:80,v/v） as the mobile phase at a flow rate of 0.8 mL/min.The calibration curve obtained was linear（r≥0.99） over the concentration range of 0.50-600.29 ng/mL for pravastatin and 20.07-2012.00 ng/mL for aspirin.Method validation was performed as per FDA guidelines and the results met the acceptance criteria.A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day.The proposed method was found to be applicable to clinical studies.
文摘Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.
文摘A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric （LC MS/ MS） assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and g.）imepiride in human plasma. Carbamazepine was used as internal standard （IS）. The analytes were extracted from 200 μL aliquots of human plasma via protein precipitation using acetonitrile, The reconstituted samples were chromatographed on a Alltima HP C18 column by using a 60：40 （v/v） mixture of acetonitrile and 10 mM ammonium acetate （pH 3.0） as the mobile phase at a flow rate of 1.1 mL/min. The calibration curves obtained were linear （r2〉0.99） over the concentration range of 0.50-150.03 ng/mL for atorvastatin, 12.14-1207.50 ng/mL for metformin and 4.98-494.29 ng/mL for glimepiride. The API-4000 LC-MS/MS in multiple reaction monitoring （MRM） mode was used for detection. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. All the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 rain for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers.
