Sensitive Method For Estimation Research Articles

Development and Validation of New Analytical Method for Estimation of Anthelmintic in Tablet Dosage Form

A rapid, sensitive and accurate method for Estimation of Anti- Histamine in Tablet Dosage Form by RP-HPLC. Mobile phase was Methanol: 0.1% Ortho phosphoric acid (80:20% v/v). Flow rate was 0.9 ml/min. The detection Wavelength was 227 nm. The injection volume was 20-µl. The proposed method was validated for selectivity, precision, linearity, and accuracy. All validation parameters were within the acceptable range. Linearity studies for Levamisole was performed (10-60µg/ml). The %RSD for accuracy found to be less than2%. Assay was found to be 99.17 to 101.65 respectively The range of 10-60µg /ml was selected for the linearity of a standard Levamisole. The 80%, 100% and 120% levels of recovery study were selected to perform the recovery study. Linearity studies for Levamisole was performed on (10-60µg /ml).

Development and Validation of New Analytical Method for Estimation of Anti-histamine in Tablet Dosage Form

A rapid, sensitive and accurate method for Estimation of Anti- Histamine in Tablet Dosage Form by RP-HPLC. Mobile phase was Methanol: 0.1%. Ortho phosphoric acid (80:20% v/v). Flow rate was 0.9ml/min. The detection Wavelength was 227nm. The injection volume was 20µl.The proposed method was validated for selectivity, precision, linearity, and accuracy. All validation parameters were within the acceptable range. Linearity studies for Rupatadine Fumarate were performed (10-60µg/ml). The %RSD for accuracy found to be less than 2%. Assay was found to be 99.17 to 101.65 respectively. The range of 10-60µg /ml was selected for the linearity of a standard Rupatadine Fumarate. The 80%, 100% and 120% levels of recovery study were selected to perform the recovery study. Linearity studies for Rupatadine Fumarate was performed on (10-60µg/ml).

Development and Validation of Stability Indicating RP-HPLC Method for Estimation of Levamisole HCl in Bulk and Tablet Dosage Form

A rapid, sensitive and accurate method for Estimation of Anti- Histamine in Tablet Dosage Form by RP-HPLC. Mobile phase was Methanol: 0.1% Ortho phosphoric acid (80:20% v/v). Flow rate was 0.9ml/min. The detection Wavelength was 227nm. The injection volume was 20-µl. The proposed method was validated for selectivity, precision, linearity, and accuracy. All validation parameters were within the acceptable range. Linearity studies for Levamisole was performed (10-60µg/ml). The %RSD for accuracy found to be less than2%. Assay was found to be 99.17 to 101.65 respectively The range of 10-60µg /ml was selected for the linearity of a standard Levamisole. The 80%, 100% and 120% levels of recovery study were selected to perform the recovery study. Linearity studies for Levamisole was performed on (10-60µg/ml).

RP-HPLC Method development and validation for simultaneous estimation of montelukast and ebastine in pharmaceutical dosage form

Combination therapy of Montelukast (MNK) and Ebastine (EBA) provide anti-asthmatic effector the maintain treatment of asthma and relieve symptoms of allergies. The objective of this study is development of a new simple, accurate, sensitive, and reproducible RP-HPLC method for simultaneous estimation of MNK and EBA in pharmaceutical formulation (tablet) using Ofloxacin (OFL) as an internal standard and validate the same as per ICH guidelines. The chromatogram separation was achieved on Qualisil-5 BDS C8 column (250 mm × 4.6 mm, 5µm) column with mobile phase acetonitrile: water (pH 2.8 with TFA) in the composition of 84:16 v/v at a flow rate of 1 mL/min using PDA detector at 254 nm at ambient column temperature, keeping the injection volume 20 μL. The retention time of OFL, MNK, and EBA was observed to be 2.107 min, 2.517 min, and 3.819 min, respectively. All the criteria for the validation (linearity, accuracy, precision, and robustness) were observed to be within the acceptation range. The calibration plots were obtained between 5-60 µg/mL for MNK and 5-60 µg/mL for EBA with r2 values of 0.999 in each case. The recovery of MNK and EBA was found to be 98.99% and 99.40%, respectively with a % RSD of <2. This RP-HPLC method was found to be rapid, specific, precise, and accurate and can be used for the routine analysis of MNK and EBA in bulk as well as in tablet dosage form. The separation was complete with a shorter analysis time along with well good resolved peak.

The impact of ADHD genetic risk on educational achievement: a comparative cross-national study

Abstract Human capital accumulation is a key driver of economic development across countries. Although previous studies have shown that country-specific circumstances (e.g., cultural, health-related, and educational factors) are strongly related with the accumulation of human capital in society, few studies have explored the importance of innate ability factors in general and ADHD-related behavioral symptoms in particular for cognitive skill outcomes. This paper hypothesizes and empirically establishes the educational burden of the ADHD-related behavioral symptoms on aggregate cognitive achievement outcomes. We use a novel compilation of the 2- and 7-repeat allele variants of the human DRD4 exon III gene that candidate gene association studies have identified as an important biomarker in the etiology of childhood ADHD. We find that our indicator for the prevalence of ADHD genetic risk in society has a negative and statistically significant impact on educational achievement. Additional sensitivity tests and estimation methods further corroborate our main hypothesis.

Chemometrics-assisted development of a validated LC method for simultaneous estimation of temozolomide and γ-linolenic acid: Greenness assessment and application to lipidic nanoparticles

The described work entails the development of a simple, sensitive, green, and robust high-performance liquid chromatographic (HPLC) method for simultaneous estimation of temozolomide (TMZ) and γ-linolenic acid (GLA). The chemometric factor screening study helped identify the critical method parameters optimized using Box-Behnken design for improved understanding and enhancing the method performance. Chromatographic separation was performed on a Kinetex® C18 column (150 × 4.6 mm, 5 µm particle size) using methanol: water (pH adjusted to 3.5 using 0.5% v/v O-phosphoric acid) as the mobile phase at 0.5 mL/min flow rate and diode array detection between 210 and 360 nm. The linearity of the method was observed for concentrations of TMZ and GLA ranging between 1 and 100 µg.mL−1 (R2 = 0.999, p < 0.05). Accuracy evaluation showed good percent recovery within 97.9–100%, while intra- and inter-day precision showed RSD values within 0.37%-1.01%. The limit of detection and quantification for TMZ was found to be 0.75 and 1.0 μg.mL−1, respectively, while the values 0.55 and 1.0 μg.mL−1, respectively, were observed for GLA. System suitability (96.9–102.8%), its limits, and robustness evaluation indicated good percent recovery within, while RSD values were found to be within the acceptable limit of less than 2%. The method was specific for its ability to detect the analytes and their degradation products during forced degradation studies, which also indicated that TMZ was highly prone to alkaline conditions while GLA showed mild degradation in all the studied conditions. The estimation of both the analytes from lipid nanoparticles formulation showed good values for total drug content (82.6–85.3%), entrapment efficiency (95.4 to 98.7%), and drug loading (25.2 to 38.4%). Overall, the results indicated that the developed method was reliable for its accuracy, precision, sensitivity, and specificity for simultaneous estimation of the analytes. The method was found to be stability-indicating in nature and suitable for simultaneous estimation of TMZ and GLA from the developed nanoparticles formulation. Further, employing a greenness assessment approach established the method greenness.

Selective SGLT2 Inhibitor’s Estimation and Validation from Galenical Form by RP-HPLC Method

Aim: The recent analysis is required to do novel and simple, sensitive, precise, efficient, instant and reproducible reverse phase high performance liquid chromatography (RP-HPLC) method for estimation of antidiabetic drug in the unit dosage form. Validation of this method is also planned to make it suitable for the actual use.&#x0D; Study Design: Department of Pharmaceutical Chemistry, Datta Meghe Institute of Medical Sciences deemed to be university, Wardha in collaboration with Balkh university, Mazar-e-sharif, Afghanistan between August 2021 and December 2021.&#x0D; Methodology: In that article develop the method and validate it by estimation of antidiabetic drugs in solid dosage form by RP-HPLC, by using System suitability test, Repeatability, Precision studies (Intra-day and Interday/Intermediate), Linearity/Calibration studies, Robustness, Force degradation, Specificity, Drug recovery/accuracy studies.&#x0D; Results: as per ICH guidelines, the performance if system suitability in remogliflozin were achieved all guidelines; in that, tailing factor (T),separation factors(α),theoretical plates(N),capacity factor (k’), resolution (R) and RSD (%). The validated stress degradation studies under thermal, oxidative, alkali and acid, in few degradation products for remogliflozin (REM).&#x0D; Conclusion: From the results we conclude that, this novel technique which validated for exploration by reverse phase high performance liquid chromatography (RP-HPLC) should be used for routine quality control of remogliflozin (REM) prediction from developed formulation.

JOM-4S Overhauser Magnetometer and Sensitivity Estimation.

The Overhauser magnetometer is a scalar quantum magnetometer based on the dynamic nuclear polarization (DNP) effect in the Earth’s magnetic field. Sensitivity is a key technical specification reflecting the ability of instruments to sense small variations of the Earth’s magnetic field and is closely related to the signal-to-noise ratio (SNR) of the free induction decay (FID) signal. In this study, deuterated 15N TEMPONE radical is used in our sensor to obtain high DNP enhancement. The measured SNR of the FID signal is approximately 63/1, and the transverse relaxation time T2 is 2.68 s. The direct measurement method with a single instrument and the synchronous measurement method with two instruments are discussed for sensitivity estimation in time and frequency domains under different electromagnetic interference (EMI) environments and different time periods. For the first time, the correlation coefficient of the magnetic field measured by the two instruments is used to judge the degree of the influence of the environmental noise on the sensitivity estimation. The sensitivity evaluation in the field environment is successfully realized without electrical and magnetic shields. The direct measurement method is susceptible to EMI and cannot work in general electromagnetic environments, except it is sufficiently quiet. The synchronous measurement method has an excellent ability to remove most natural and artificial EMIs and can be used under noisy environments. Direct and synchronous experimental results show that the estimated sensitivity of the JOM-4S magnetometer is approximately 0.01 nT in time domain and approximately 0.01 nT/ in frequency domain at a 3 s cycling time. This study provides a low-cost, simple, and effective sensitivity estimation method, which is especially suitable for developers and users to estimate the performance of the instrument.

Analytical and bioanalytical HPLC method for simultaneous estimation of 5-fluorouracil and sonidegib.

Aim: To develop a new sensitive RP-HPLC method for simultaneous estimation of 5-fluorouracil (5-FU) and sonidegib (SDG). Materials & methods: Analytical and bioanalytical methods for simultaneous quantification of 5-FU and SDG in bulk, nanoformulations and in rat plasma were developed and validated using a gradient elution technique. Results: Separation of the analytes was effected on a Luna® C18 LC column using a mobile mixture comprising acetonitrile and acidified water. 5-FU and SDG were extracted from plasma matrix using liquid-liquid extraction. The applicability of the method was verified through single-dose oral pharmacokinetic study in Wistar rats. Conclusion: The developed methods allow a specific, sensitive and steady analytical procedure for the simultaneous estimation of 5-FU and SDG in nanoformulations and biological matrix.

Introduction of an Innovative approach for Bioanalytical Method Development and Validation of Febuxostat by using LC-ESI-MS/MS in Human Plasma

The aim of the present work is to develop and validate an accurate, sensitive, rapid, precise, and simple bioanalytical method for estimation of Febuxostat in human plasma by using LC-ESI-MS/MS. The method was developed by gradient elution technique with the combination of the mobile phase as 0.1% Formic Acid in Milli-Q water and 0.1% Formic Acid in Acetonitrile at a flow rate of 0.5ml/min. The Analyte and IS (Tolbutamide) were separated by a C18 Phenomenex Kinetex (50x3mm, 5µ) column. The chromatographic run time was 7.0 minutes. The plasma extraction was done by a simple protein precipitation technique (PPT). The LOD and LLOQ were found to be 6.25ng/ml and 125ng/ml, respectively. The extraction recovery of the drug from plasma was more than 90%. The validation parameters were found within the range, as mentioned by USFDA and EMA guidelines.

Evaluation and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method

A Novel, accurate, precise and sensitive reversal indirect spectrophotometric method for estimation of Atorvastatin Calcium (ATOR) has been proposed. The method is based on an oxidation of (ATOR) with of excess of KIO4 as oxidant agent. Where, the remaining of oxidant KIO4 reacts with the Para – Anisidine (P-ANS) in acidic medium, the resulting yellowish dye complex exhibit a maximum absorption at 538.0 nm, this spectrum generated revers pack at 428 nm was certified for reverse estimation. Beer's law is obeyed over the concentration range from (5-170 µg/ml) by applying univarate techniques, tow model of multivariate techniques has been applied; Central Composite Design (CCD) and Box-Benhken Design (BBD). By using multivariate techniques, ATOR was obeyed Beer's law at concentration range from (5-185µg/ ml) and (3-188µg/ ml) for (CCD) and (BBD) techniques, respectively. This method had a good accuracy (relative error RE % in the range of (±2.386%, ±2.202% and ± 0.688) good precision (relative standard deviation RSD% is better than ±2.5833%, ±2.0522% and ±1.4177), and the limit of detection (LOD) is (0.14384, 0.12617 and 0.10588 µg/ml) and the limit of quantitation (LOQ) is (0.43590, 0.38235 and 0.32085µg/ml) for univarate, (CCD) and (BBD) techniques, respectively. The method has been applied successfully for assay of Atorvastatin Calcium in pure forms and pharmaceutical preparation forms. How to Cite this Article Pubmed Style Hasan MA, Hasan RO, Al-Rawi KF. and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. SRP. 2020; 11(9): 248-259. doi:10.31838/srp.2020.9.41 Web Style Hasan MA, Hasan RO, Al-Rawi KF. and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. http://www.sysrevpharm.org/?mno=6466 [Access: March 30, 2021]. doi:10.31838/srp.2020.9.41 AMA (American Medical Association) Style Hasan MA, Hasan RO, Al-Rawi KF. and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. SRP. 2020; 11(9): 248-259. doi:10.31838/srp.2020.9.41 Vancouver/ICMJE Style Hasan MA, Hasan RO, Al-Rawi KF. and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. SRP. (2020), [cited March 30, 2021]; 11(9): 248-259. doi:10.31838/srp.2020.9.41 Harvard Style Hasan, M. A., Hasan, . R. O. & Al-Rawi, . K. F. (2020) and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. SRP, 11 (9), 248-259. doi:10.31838/srp.2020.9.41 Turabian Style Hasan, Marwan A., Rebwar O. Hasan, and Khalid F. Al-Rawi. 2020. and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Reviews in Pharmacy, 11 (9), 248-259. doi:10.31838/srp.2020.9.41 Chicago Style Hasan, Marwan A., Rebwar O. Hasan, and Khalid F. Al-Rawi. Evaluation and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. Systematic Reviews in Pharmacy 11 (2020), 248-259. doi:10.31838/srp.2020.9.41 MLA (The Modern Language Association) Style Hasan, Marwan A., Rebwar O. Hasan, and Khalid F. Al-Rawi. Evaluation and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Method. Systematic Reviews in Pharmacy 11.9 (2020), 248-259. Print. doi:10.31838/srp.2020.9.41 APA (American Psychological Association) Style Hasan, M. A., Hasan, . R. O. & Al-Rawi, . K. F. (2020) and Comparison of the Optimization Parameters Based on Univariate and Multivariate Techniques for Estimation Atorvastatin Calcium with Novel Reverse Indirect Spectrophotometric Reviews in Pharmacy, 11 (9), 248-259. doi:10.31838/srp.2020.9.41

Developing a Validated HPLC Method for Quantification of Ceftazidime Employing Analytical Quality by Design and Monte Carlo Simulations.

Ceftazidime, a third-generation cephalosporin, is widely used in the treatment of lung infections, often given as "off-label" nebulization. There is a need to develop a sensitive and robust analytical method to compute aerodynamic properties of ceftazidime following nebulization. The current study entails development of a simple, accurate, and sensitive HPLC method for ceftazidime estimation, employing the principles of analytical quality-by-design (AQbD) and Monte Carlo simulations. Selection of critical material attributes (CMAs) affecting method performance was accomplished by factor screening exercises. Subsequently, the influential CMAs, i.e., mobile phase ratio and flow rate, were systemically optimized using a face-centered cubic design for the chosen critical analytical attributes (CAAs). The factor relationship(s) between CMAs and CAAs was explored employing a 3 D-response surface and 2 D-contour plots, followed by numerical as well as graphical optimization, for establishing the optimal chromatographic conditions. The obtained method operable design region was validated by Monte Carlo simulations for defect rate analysis. The optimized HPLC conditions for estimating ceftazidime were acetonitrile to acetic acid solution (75:25) as mobile phase at a flow rate of 0.7 mL/min, leading to Rt of 4.5 min and peak tailing ≤2. Validation studies, as per International Conference on Harmonization Q2(R1) guidance, demonstrated high sensitivity, accuracy, and efficiency of the developed analytical method with an LOD of 0.075 and LOQ of 0.227 µg/mL. Application of this chromatographic method was extrapolated for determining aerodynamic performance by nebulizing ceftazidime at a flow rate of 15 L/min using a next-generation impactor. The study indicated superior performance, sensitivity, and specificity of the developed analytical system for quantifying ceftazidime. Application of an AQbD approach, coupled with Monte Carlo simulations, aided in developing a robust HPLC method for estimationof ceftazidime per se and on various stages of impactor. (i) QbD-enabled development of robust RP-HPLC method for ceftazidime quantification, (ii) Analytical method optimization employing Risk Assessment and Design of Experiments, (iii) Design space verification and defect rate analysis using Monte Carlo simulations, (iv) Chromatographic method validation as per ICH Q2 R1 guidelines and (v) Quantitative estimation of ceftazidime on various stages of impactor.

Simple RP-HPLC method for Aceclofenac quantitative analysis in pharmaceutical tablets

A reverse phase liquid chromatographic method for estimation of Aceclofenac in bulk drug and tablet dosage form was developed and validated. The chromatographic conditions to achieve the highest performance parameters using octylsilyl column with guard filter were optimized. The separation was carried out using a mobile phase containing 10 mM Phosphate Buffer, pH 2.1 and methanol (30:70% v/v) pumped at a flow rate of 1.0 mL/min with detection at 272 nm. The method was shown to be linear in 19.8–148.5 μg/mL concentration range (regression coefficient of 0.999). The limit of detection (LOD) and limit of quantification (LOQ) was found to be 0.0692 μg/mL and 0.2076 μg/mL, respectively. The accuracy of the method was assessed by adding fixed amount of pre-analyzed sample to different standard solutions (80%, 100%, and 120% of the tested concentration) in triplicate. The percentage mean recoveries were 97.91% to 100.39% with %RSD values of 0.64–0.79. The method was found to be precise with %RSD value of 1.13 and 1.60 for intraday and interday precision study, respectively. The method specificity and robustness were also established. New and sensitive HPLC method for estimation of Aceclofenac has been developed, in respect to the reviewed analytical methods.

Spectrophotometric Determination of Ampicillin with Sulfanilic Acid by Oxidative Coupling Reaction

Sensitive, economic, simple and accurate spectrophotometric method for estimation of ampicillin in bulkand dosage form is described. Ampicillin was oxidized by sodium hypochlorite and coupling with sulfanilicacid in the presence of sodium hydroxide to obtain a stable yellow colored chromogen which exhibit amaximum absorption (?max) at 400 nm. The optimum conditions were carefully evaluated .Plot of absorbance against concentration was linear over the range (50-300 µg.ml-1). This method was applied tothe estimation of ampicillin in pure drug and commercial formulations successfully.

A Novel Validated Eco-friendly RP-UHPLC Method for Assay and Related Substances in Meropenem

A simple, rapid, sensitive, specific, eco-friendly and stability-indicating linear gradient liquid chromatographic method (RP-UHPLC) for simultaneous estimation of assay and its related compounds in Meropenem API samples is developed and validated. Chromatographic separation was achieved on Zorbax Eclipse plus C18, (100 x 4.6) mm, 3.5 µm RRLC short column and 10 mM potassium dihydrogen orthophosphate is used as buffer, buffer solution used as eluent A and buffer and acetonitrile combination 30: 70 v/v ratio used as eluent B and Agilent RRLC (UHPLC) system is used for analysis. The mobile phase flow rate was 1.0 ml/min, and the eluted compounds were monitored at 220 nm for related substance method and 290 nm for assay method. Excellent resolution was obtained between Meropenem and its related compounds which were eluted within 10 min. The correlation co-efficient(r) is > 0.995 for both the methods from linearity data and percentage of recovery is 98.0 to 102.0 and 80.0 to 120.0 % for assay method and for related substance method respectively. Sensitivity of the method is found to be less than 0.316 µg/ml. Peak homogeneity data for Meropenem in the chromatograms from the stressed samples were obtained by using photodiode array detector demonstrated the specificity of the method for analysis of Meropenem in presence of the degradation compounds. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, and robustness.

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE SIMULTANEOUS ESTIMATION OF CEFOPERAZONE AND SULBACTAM IN RAT PLASMA AND ITS IMPORTANCE IN THERAPEUTIC DRUG MONITORING

Objective: To study the Therapeutic drug monitoring and pharmacokinetics of marketed antibiotics formulation by developing a sensitive and specific Bioanalytical Chromatographic method.&#x0D; Methods: In the present study, we developed a rapid, sensitive and selective chromatographic method for simultaneous estimation of Cefoperazone (CEF) And Sulbactam (SAL) in male Wistar rat plasma. A novel liquid phase extraction method has adopted the preparation of plasma sample preparation. The CEF and SAL were eluted on a peerless Basic C18 (25 cm; 4.6 mm x 5 µm) column maintained at controlled environmental conditions. The gradient mobile phase comprised of 10 mmol ammonium acetate and acetonitrile. A UV detector was set at 250 nm and retention times for CEF and SAL were approximately 5.6 and 14.2 min, respectively. The proposed HPLC method was validated according to the US FDA guidelines with respect to the linearity, accuracy, precision, detection and quantitation limits, robustness and specificity.&#x0D; Results: Calibration curves of CEF and SAL were linear across the concentration range of 600-1000 and 6-10 µg/ml, with correlation coefficients (r2)&gt;0.9977 and (r2)&gt;0.9987, respectively. The limits of detection for CEF and SAL were 70.48 and 0.35 µg/ml, respectively. Additionally, CEF and SAL were stable in plasma for at least 24 h when stored at room temperature and 2-8 °C. &#x0D; Conclusion: The developed chromatographic method was effectively utilized to measure the plasma CEF and SAL concentrations in a pharmacokinetics study after intravenous injection to the healthy male Wistar rats.

Development and Validation of Zero and First Order Derivative Area Under Curve Spectrophotometric Methods for Pyrazinamide in Bulk Material and Pharmaceutical Formulation

Introduction: The aim of this work is to establish a novel, simple, precise and sensitive UV-AUC spectrophotometry method for estimation of Pyrazinamide from bulk and in-Pharmaceutical formulation and validate it according ICH guidelines. Pyrazinamide is used for the treatment of tuberculosis.

Quantitation of RNA by a fluorometric method using the SYTO RNASelect stain

Quantitation of even trace amounts of RNA has biological significance. However, existing methods of RNA estimation are not capable of eliminating the interference of other impurities, especially DNA. In this study, we developed a rapid and sensitive method for fluorometric estimation of RNA using an RNA-specific dye, SYTO RNASelect. A good linear correlation between the fluorescence intensity and RNA concentration was observed using this method. The maximal fluorescence intensity of DNA was only 2.9% of the fluorescence intensity of 40 μg/mL RNA, demonstrating the high RNA specificity of the SYTO RNASelect method.

A sensitive RP-HPLC method for estimation of artemether from polymeric nanoparticles after pre-column acid treatment using UV-visible detector

Artemether; a sesquiterpene lactone is widely used for the treatment of malaria as artemisinin-based combination therapy (ACT). The present work involves the development and validation of sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method for quantification of artemether (ART) in polymeric nanoparticles. ART was transformed to α, β-unsaturated decalones by pre-column acid treatment to enhance the sensitivity of chromophoric group lacking ART for quantification by HPLC-UV. Waters Spherisorb® 5 µm ODS(C18) column (4.6*250 mm) with gradient elution by mobile phase comprising of ACN and PBS (10 mM; pH 6.0) was used to separate acid-treated ART. The analysis was carried at λmax of 253 nm with 20 min and 20 µL run time and injection volume, respectively. The method was found to be linear in the concentration range of 0.5–10 µg mL−1 with 0.09 µg mL−1 and 0.27 µg mL−1 as LOD and LOQ respectively. Further, the method was also found to be specific for ART in presence of blank polymeric nanoparticles, accurate (% average recovery rate 101.7 ± 1.68%), precise (RSD <2%), and robust. The method was successfully used to determine % entrapment efficiency and in vitro release of ART-loaded polymeric nanoparticles with HPLC using a UV-visible detector.

Assessing the performance of climate change simulation results from BESM-OA2.5 compared with a CMIP5 model ensemble

Abstract. The main features of climate change patterns, as simulated by the coupled ocean–atmosphere version 2.5 of the Brazilian Earth System Model (BESM), are compared with those of 25 other CMIP5 models, focusing on temperature, precipitation, atmospheric circulation, and radiative feedbacks. The climate sensitivity to quadrupling the atmospheric CO2 concentration was investigated via two methods: linear regression (Gregory et al., 2004) and radiative kernels (Soden and Held, 2006; Soden et al., 2008). Radiative kernels from both the National Center for Atmospheric Research (NCAR) and the Geophysical Fluid Dynamics Laboratory (GFDL) were used to decompose the climate feedback responses of the CMIP5 models and BESM into different processes. By applying the linear regression method for equilibrium climate sensitivity (ECS) estimation, we obtained a BESM value close to the ensemble mean value. This study reveals that the BESM simulations yield zonally average feedbacks, as estimated from radiative kernels, that lie within the ensemble standard deviation. Exceptions were found in the high latitudes of the Northern Hemisphere and over the ocean near Antarctica, where BESM showed values for lapse rate, humidity feedback, and albedo that were marginally outside the standard deviation of the values from the CMIP5 multi-model ensemble. For those areas, BESM also featured a strong positive cloud feedback that appeared as an outlier compared with all analyzed models. However, BESM showed physically consistent changes in the temperature, precipitation, and atmospheric circulation patterns relative to the CMIP5 ensemble mean.