Novel sequential immunocapture microflow LC/MS/MS approach to measuring PTH-Fc protein in human serum

The quantitation of PTH-Fc in circulation by ligand binding assay presented a significant challenge due to the extremely low doses of administration, interference from the endogenous. A robust LC–MS/MS method to quantify the extremely low concentration of PTH-Fc in human serum utilized sequential immunoaffinity enrichment at PTH and Fc domains in conjunction with microflow LC–MS/MS technology significantly improved the sensitivity and selectivity. The assay displayed a quantitation range of 0.025–5.0 ng/ml and acceptable intraday and interday precision (%CV ≤ 15%) and accuracy (%bias ≤ ±15%) and can be routinely used for pharmacokinetic measurement of the drug. The novel sequential immunocapture workflow described herein can be applied to the quantitation of other recombinant therapeutic proteins to support clinical studies.

Poly(4-vinylphenol) coated magnetic nanoparticles based dispersive solid-phase microextraction of the determination of mercury(II) in water

<p>The development of magnetic sorbent for dispersive solid-phase micro-extraction (DmSPE) often requires lengthy multi-step reactions. This research revealed a simplified method for preparing magnetic sorbent for the DmSPE using poly(4-vinylphenol) (PVP). The magnetic sorbent (PVP@MNP) was prepared by coating PVP on magnetic particles (MNP). The characterization and formation of PVP@MNP were confirmed using infrared spectroscopy, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The primary goal of this study is to develop a sensitive DmSPE method to analyze Hg2+ in water using PVP@MNP as a magnetic sorbent. The preparation of PVP@MNP was performed in a simple coating method at room temperature. Briefly, the PVP@MNP was prepared by sonicating the mixture of MNP and PVP. This sorbent was then used as a magnetic sorbent for the extraction of Hg2+ from water. The developed PVP@MNP based DmSPE reached a low method of detection limit (0.01 μg L-1) and limit of quantification (0.04 μg L-1). This method also showed a wide linearity range (100 - 2000 µg L-1) with a good correlation factor under optimized conditions. The developed method showed good recovery (72-90%) with good intraday and interday precision. This study also showed that the developed DmSPE method was effectively used to determine Hg2+ in drinking water, mineral water, and surface water. The result also demonstrated that PVP@MNP is reusable.</p>

RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF METFORMIN HCL AND CANAGLIFLOZIN IN PHARMACEUTICAL FORMULATION

A simple, specific, accurate, precise and stability-indicating RP-HPLC method was developed and validated for the simultaneous estimation of metformin HCl and canagliflozin in pharmaceutical formulation. The method was developed using the Altima C8 column (150 ×4.6 mm, 0.5 μm) with a mobile phase consisting of acetonitrile and 0.1 % orthophosphoric acid in water (62:38 %V/V) with a flow rate of 1 mL/min. Detection was carried out at 254 nm using a PDA detector. The retention time for metformin HCl and canagliflozin was found to be 2.282 and 3.339 min, respectively. The proposed method was validated for linearity, range, accuracy, precision, robustness, LOD and LOQ. Linearity was observed over a concentration range 15-225 μg/mL for metformin HCl (r2 =0.9995) and 5-40 μg/mL for canagliflozin (r2 =0.9988). The % RSD for intraday and interday precision was found to be 0.13 and 0.20 for metformin HCl and 0.18 and 0.20 for canagliflozin. The LOD and LOQ were found to be 0.16 μg/mL and 0.54 μg/mL for metformin HCl and LOD and LOQ were found to be 0.05 and 0.21 μg/mL for canagliflozin. Metformin HCl and canagliflozin were subjected to stress conditions of degradation including acidic, alkaline, oxidative, thermal and photolysis.

Pharmacokinetic and Bioavailability Studies of Galgravin after Oral and Intravenous Administration to Rats Using HPLC-MS/MS Method

This paper presents a new high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method with a rapid analysis of 6 min to determine the concentration of galgravin in rat plasma so as to study its pharmacokinetic features and bioavailability in vivo. Schisandrin was selected as the internal standard (IS). After extracting the analyte from plasma samples with ethyl acetate, methanol-H2O (0.1% formic acid) (85 : 15, v / v ) was used as mobile phase to achieve chromatographic separation on a C18 reversed phase column. The MS detection was performed in positive ion mode using electrospray ionization (ESI) source. This method showed good linearity over the range of 1~500 ng/mL ( R 2 > 0.999 ), and the lower limit of quantitation (LLOQ) was 1.0 ng/mL. The intraday precision and interday precision were both within 8.5%, whereas the accuracies were in the range of -2.6%–6.0%. The average recoveries of galgravin in rat plasma were between 92.3% and 99.3%. Moreover, galgravin was stable throughout storage and processing with all RSDs below 12.1%. After the successful application of this optimized method, the oral bioavailability of galgravin was determined to be 8.5%. This study will be helpful to the future research and development of galgravin.

ULTRAVIOLET SPECTROPHOTOMETRIC METHOD DEVELOPMENT FOR ESTIMATION OF NEW ANTIVIRAL REPURPOSING DRUG FAVIPIRAVIR

Objective: A new, economical, precise, linear, sensitive, accurate, ultraviolet (UV) spectrophotometric method for the estimation of new antiviral repurposing drug favipiravir as there is no reported simple UV spectrophotometric method for estimation. The efforts were made for development and validation of favipiravir as per ICH guidelines, because drug has a wide scope for formulations to be developed for treating different viruses. Methods: This method was developed using ethanol and water as a solvent. Favipiravir showed the absorption maxima at 234 nm. A Shimadzu UV–visible spectrophotometer (UV JAPAN 1801) was used to carry out spectral analysis. Results: The developed method was linear for a range of 0–10 μg/ml and displayed a good correlation coefficient of 0.9995. Accuracy of the method was estimated using a recovery study. The amount of drug recovered was found to be in the range of 99.30–99.91%. The % relative standard deviation value of intraday precision was found to be 0.408% and interday precision was found to be in the range of 0.348–0.693%. The % relative standard deviation found to be <2 which are indicative of the precision and reproducibility of the method. Detection limit and quantitation limit were noticed as 0.095 and 0.290, respectively. Conclusion: The developed UV spectrophotometric method was validated statistically for linearity, accuracy, precision, and sensitivity and results proved that the method can be employed for routine analysis of favipiravir.

Microwave-Assisted Extraction Coupled with Mass Spectrometry for Determining Five Volatile Compounds from Soy Sauces

As a popular fermented condiment in oriental countries, soy sauce plays a more and more important role in modern food culture due to its unique smell and delicious taste. With the help of microwave extraction and gas chromatography-tandem mass spectrometry, the sample preparation method is aimed to determine the content of cyclohexane, benzene, toluene, chlorobenzene, and styrene in soy sauce. The method was validated by examining the linearity, accuracy, specificity, precision, the limit of detection, and quantitation. Meanwhile, three key factors have an impact on the efficiency and accuracy of the method including extracting solvent, temperature, and time which were optimized. The result shows that the recoveries of spiked analytes ranged from 80.86% to 105.71%, the relative standard deviation of intraday and interday precision was no more than 12.1% and 12.5%, and the limit of detection and quantitation were 0.25–1.00 ng/mL and 0.50–2.00 ng/mL, respectively. The results also indicated that the proposed method was a simple, reliable, and sensitive approach for the determination trace amount of five harmful volatile organic compounds from soy sauce.

Quantitative Determination of 7 Saikosaponins in Xiaochaihu Granules Using High-Performance Liquid Chromatography with Charged Aerosol Detection

Bupleuri Radix (Chaihu, in Chinese) is the principal drug in Xiaochaihu granules (XGs) that is a famous Chinese medicine preparation in China. Since previous analytical methods have not focused on the multiactive saikosaponins of Chaihu, it is difficult to effectively control the quality of XG on the market. In this manuscript, the simultaneous determination of 7 saikosaponins (saikosaponins C, I, H, A, B2, G, and B1) in XG by HPLC with charged aerosol detection (CAD) and confirmation by LC-Q-Orbitrap HRMS were described. The saikosaponins were purified on an SPE cartridge and determined on a Waters CORTECTS C18 column (4.6 mm × 150 mm, 2.7 μm) by gradient elution using 0.01% acetic acid aqueous solution and acetonitrile. The results showed good linearity with the r2 values higher than 0.998 for all analytes. The average recoveries at three different concentration levels ranged from 80% to 109% and the intraday and interday precision (relative standard deviations, RSD%) were in the range of 1.0%∼1.9% and 1.4%∼2.1%, respectively. The established HPLC-CAD method was subsequently applied to 15 batches of XG to investigate the batch-to-batch consistency and controllability. The proposed method could potentially be used for the quality control of XG and also be helpful in the quality evaluation of Chaihu and its related preparations.

A VALIDATED STABILITY INDICATING UV-SPECTROPHOTOMETRIC SIMULTANEOUS ESTIMATION OF ROSUVASTATIN CALCIUM AND FENOFIBRATE IN BULK AND PHARMACEUTICAL FORMULATION

Objective: The present work deals with the development and validation of the absorbance ratio method for the estimation of rosuvastatin calcium and fenofibrate in bulk and pharmaceutical formulation. Studied forced degradation characteristics of bulk and pharmaceutical formulation as per stability guidelines. Methods: The bulk and pharmaceutical formulation studied by the absorbance ratio method. It is the ratio of absorbances at two selected wavelengths. One wavelength is the isoabsorptive point and another wavelength is λ max of one of the components. From the overlay spectra of the two drugs, ROS and FEN showed the isoabsorptive point at 249.5 nm. The second wavelength used was 287 nm, which was the λ max of FEN. Results: The drugs obeyed Beer's law and showed a good correlation. The correlation coefficient for the ROS was 0.999 and for FEN 0.999. The RSD for intraday precision was 0.57 for ROS and 0.057 for FEN. The interday precision was 0.05 for ROS and 0.03for FEN, respectively. The detection limit and quantification limit were found to be 0.048 and 0.14 μg/ml for ROS and 0.069 and 0.21μg/ml for FEN, respectively. More degradation was found in acid hydrolysis and photostability degradation. Conclusion: A simple, precise, accurate, validated, stability-indicating method for simultaneous estimation of rosuvastatin calcium and fenofibrate in bulk and pharmaceutical formulation has been developed.

Simultaneous Determination of Ropivacaine and 3-Hydroxy Ropivacaine in Cerebrospinal Fluid by UPLC-MS/MS

In this paper, a UPLC-MS/MS method was developed for the determination of ropivacaine and its metabolite 3-hydroxy ropivacaine in cerebrospinal fluid. The cerebrospinal fluid was processed by ethyl acetate liquid-liquid extraction. The multiple reaction monitoring (MRM) mode was used for quantitative analysis by monitoring the transitions of m/z 275.3 → 126.2 for ropivacaine, m/z 291.0 → 126.0 for 3-hydroxy ropivacaine, and m/z 290.2 → 198.2 for the internal standard. Standard curves for ropivacaine and 3-hydroxy ropivacaine in cerebrospinal fluid were conducted over the concentration range of 0.2–2000 ng/mL, demonstrating excellent linearity, and the lower limit of quantification was 0.2 ng/mL. The intraday precision of ropivacaine and 3-hydroxy ropivacaine was less than 11%, while the interday precision was less than 7%. The accuracy ranged between 87% and 107%, the average extraction efficiency was higher than 79%, and the matrix effect was between 89% and 98%. The developed method was then applied to a case of suspected poisoning of ropivacaine.

Direct sample introduction GC-MS/MS for quantification of organic chemicals in mammalian tissues and blood extracted with polymers without clean-up

Solvent extracts of mammalian tissues and blood contain a large amount of co-extracted matrix components, in particular lipids, which can adversely affect instrumental analysis. Clean-up typically degrades non-persistent chemicals. Alternatively, passive sampling with the polymer polydimethylsiloxane (PDMS) has been used for a comprehensive extraction from tissue without altering the mixture composition. Despite a smaller fraction of matrix being co-extracted by PDMS than by solvent extraction, direct analysis of PDMS extracts was only possible with direct sample introduction (DSI) GC-MS/MS, which prevented co-extracted matrix components entering the system. Limits of quantitation (LOQ) ranged from 4 to 20 pg μL−1 ethyl acetate (PDMS extract) for pesticides and persistent organic pollutants (POPs). The group of organophosphorus flame retardants showed higher LOQs up to 107 pg μL−1 due to sorption to active sites at the injection system. Intraday precision ranged between 1 and 10%, while the range of interday precision was between 1 and 18% depending on the analyte. The method was developed using pork liver, brain, and fat as well as blood and was then applied to analyze human post-mortem tissues where polychlorinated biphenyls (PCBs) as well as dichlorodiphenyltrichloroethane (DDT) and DDT metabolites were detected.