High-throughput LC-MS/MS method with 96-well plate precipitation for the determination of arotinolol and amlodipine in a small volume of rat plasma: Application to a pharmacokinetic interaction study

Sensitive and effective method with 96-well plate for determination of levamlodipine in human plasma using LC-MS/MS

we developed an effective protein precipitation method for determination of levamlodipine in human plasma using LC-MS/MS. Sample extraction was carried out by using liquid-liquid extraction in 96-well plate format. (S)-Amlodipine-d4 was used as internal standard (IS). The chromatographic separation was achieved using Philomen Chiral MX (2) column (3 μm, 2.1 × 100 mm). Mobile phase A was comprised of Acetonitrile (ACN), Mono ethanol amine (MEA) and Iso-Propyl alcohol (IPA) (1000:1:10, v/v/v), Mobile phase B was IPA-ACN (2:1, v/v). The flow rate was 0.4 mL/min. The total run time of each sample was 4.0 min with gradient elution. LC-MS/MS spectra were generated in positive ion mode, and multiple reaction monitoring (MRM) was used to detect the following transitions: m/z 409.20 → 238.15 for levamlodipine and 415.25 → 240.20 for (S)-Amlodipine-d4 (the IS). The method was linear from 50 to 10000 pg/mL（R2＝0.9988489）,and the lower limit of quantification (LLOQ) was 50 pg/mL. This method was applied to a bioequivalence study of levamlodipine.

Rapid determination of polyethoxylated tallow amine surfactants in human plasma by LC-MSMS

The potential exposure to the widely used glyphosate-based herbicides, including attempted suicide by ingestion, is of world-wide concern. Whilst the major focus to date has been on managing exposure to the active ingredient glyphosate, it is now recognised that a common major 'inert' surfactant ingredient, polyethoxylated tallow amine (POEA) and related compounds, may be more toxic. However, the information on the toxicokinetics of POEA surfactants after exposure is limited, in part, due to the lack of suitable methods for their analysis in biological matrices. We therefore developed and validated a robust LC-MSMS method that allowed, for the first time, a rapid analysis of 11 POEA homologues in human plasma. Chromatographic separation was achieved on a Kinetex EVO C18 column under a 5 min gradient elution with mobile phase A containing water/acetonitrile/formic acid (95:5:0.1, v/v/v) and mobile phase B containing acetonitrile/water/formic acid (95:5:0.1, v/v/v). Amlodipine was chosen as the internal standard (IS) for this assay. Amlodipine-d4 would be an ideal alternative IS to expand the applicability of the established method especially in antihypertensive patients. Multiple reaction monitoring (MRM) methods were optimized for 11 POEA homologues and the IS. Sample pre-treatment was performed using simple protein precipitation with methanol at a ratio of 4:1, requiring only 20 μL plasma. The validated method showed good specificity, accuracy and precision with lower limits of quantification (LLOQ) ranging from 0.35 to 10.8 ng mL^-1 for all selected POEA homologues. The method was then used to measure concentrations of the various POEA surfactants in more than 600 human plasma samples from 151 patients admitted to hospital with acute glyphosate intoxication. The highest concentrations ranged from 1.07 ng mL^-1 for C₁₈u(EO)₄-362.70 ng mL^-1 for C₁₆s(EO)₂. The analysis of POEA surfactants plasma concentrations as described here underpins the assessment of POEA internal exposure and the relationships between POEA related glyphosate toxicity and the extent of poisoning.

Determination of 12 anti-obesity drugs in human plasma by a 96-well protein precipitation plate using HPLC-MS

An analytical method was developed and validated for the simultaneous determination of 12 anti-obesity drugs (methylephedrine (MER), amphetamine (AMP), fenfluramine (FEN), bupropion (BUP), fluoxetine (FLU), sibutramine (SIBU), bisacodyl (BISA), bumetanide (BUM), lovastatin (LOVA), simvastatin (SIM), rimonabant (RIMO), and fenofibrate (FENO)) in human plasma by a 96-well protein precipitation plate combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). The 96-well protein precipitation plate was chosen for simultaneous pretreatment of large sample volumes, making the whole process more efficient and faster. Drugs were separated on an Agilent Poroshell 120 EC-C18 column, and detected by MS/MS under multiple reaction monitoring (MRM) mode. The developed method was validated in terms of linearity, matrix effect, accuracy and precision. A good linearity was obtained in the range of 0.1-20.0 ng mL-1 for fenfluramine, bupropion, fluoxetine, sibutramine, bisacodyl, and rimonabant; and 0.5-20.0 ng mL-1 for methylephedrine, amphetamine, bumetanide, lovastatin, simvastatin, and fenofibrate with a correlation coefficient above 0.995. The method was fully validated with an acceptable accuracy of 75.63-108.21%, matrix effect of 80.41-117.71% except for fenofibrate (76.07% at low concentration levels), and precision of 0.32-13.12%. Owing to the advantages of simple operation, high accuracy and sensitivity, this method is suitable for the rapid and simultaneous detection of 12 anti-obesity drugs in human plasma, providing support for clinically monitoring the development of adverse reactions and guiding the rational and appropriate use of weight-loss drugs for obese people.

A Sensitive Spectrofluorimetric Method for Curcumin Analysis

Curcumin (CUR), a natural polyphenolic compound extracted from the rhizomes of Curcuma longa, is used as a pharmaceutical agent, spice in food, and as a dye. Currently, CUR is being investigated for cancer treatment in Phase-II clinical trials. CUR also possesses excellent activities like anti-inflammatory, anti-microbial, and anti-oxidant, therefore quality control is crucial. The present research work was to develop a new, simple, validated and time-saving rapid 96-well plate spectrofluorimetric method for the determination of CUR. The developed method was compared with routinely used high performance liquid chromatography (HPLC) technique. The developed method were found to be linear in the concentration range of 15 to 3900 ng/mL with R2 ≥ 0.9983 for spectrofluorimetric and 50-7500 ng/mL with R2 ≥ 0.9999 for HPLC method. Accuracy, intraday and interday precision was adequate, with RSD lower than the suggested limits. The limits for the detection and the quantification of CUR were 7 and 15 ng/mL for spectrofluorimetric, and 25 and 50 ng/mL for HPLC respectively. The Bland-Altman analysis demonstrated the similarities between the two methods. The 96-well plate method was successfully applied to determine CUR in solid lipid nanoparticles (SLNs) and chitosan nanoparticles (Chi-NPs). The developed spectrofluorimetric method can hence serve as a possible replacement for the HPLC method for the quantification of CUR in healthcare and food products.

Graphene quantum dot implanted supramolecular carbon nitrides with robust photocatalytic activity against recalcitrant contaminants

Graphene quantum dot implanted supramolecular carbon nitrides exhibit superior visible-light photocatalytic activity in the degradation of aqueous contaminants of emerging concern.

Detection of sivelestat and its metabolite in small volumes of plasma from Chinese ALI/ARDS patients with SIRS via high-throughput UPLC-MS/MS: A pharmacokinetic study

In this study, we developed a sensitive and efficient analytical approach combining a 96-well plate-based protein precipitation strategy with ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS/MS) in order to assess the pharmacokinetic (PK) properties of sivelestat and its metabolite XW-IMP-A in samples of plasma from ALI/ARDS patients with SIRS. The samples were separated via gradient elution with a C18 column (Phenomenex Kinetex, C18, 2.6 μm, 100 Å, 50 × 2.1 mm) using 0.1 % formic acid aqueous solution (A) and acetonitrile-methanol (1:1, V:V) (B) as a mobile phase at a 0.6 mL/min flow rate. UPLC-MS/MS spectra were generated in positive ion mode, and multiple reaction monitoring (MRM) was used to detect the following transitions: m/z 435.1 → 360.0 for sivelestat, m/z 469.0 → 394.0 for sivelestat-IS, m/z 351.0 → 276.0 for XW-IMP-A, and m/z 384.9 → 310.0 for XW-IMP-A-IS. This assay was run for 2.5 min in total, and achieved lowest limit of quantitation values of 2.0 ng/mL and 0.5 ng/mL for sivelestat and XW-IMP-A, respectively, while remaining highly linear from 2-500 ng/mL for sivelestat (r2 ≥ 0.9900) and from 0.5-125 ng/mL for XW-IMP-A (r2 ≥ 0.9900). These validated data were consistent with US Food and Drug Administration (FDA) and European Medicines Agency (EMA) acceptance criteria. In addition, this method was successfully applied to the steady-state PK evaluation of ALI/ARDS patients with SIRS.

An LC-MS/MS Method for Determination of Triple Drugs Combination of Valsartan, Amlodipine and Hydrochlorothiazide in Human Plasma for Bioequivalence Study

Background:

Current guidelines for the treatment of hypertension recommend combination therapy, which intends to control blood pressure and enhance cardiovascular protection.

Materials and Methods:

A sensitive, reliable and selective tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous quantification of amlodipine (AML), valsartan (VAL) and hydrochlorothiazide (HCTZ) in human plasma. The chromatographic system was equipped with ACE 5 C8 (50 X 2.1 mm) column and utilized a mobile phase composition of 0.5 mM Ammonium Chloride & 0.04% FA-Methanol (45:55% v/v). The method used three internal standards; AML-D4, HCTZ-D2 C13 and VAL-D3 with 10% intra- and inter-day precision, and 6% bias for all the analytes.

Results:

The assay was found to be linear with R-2 > 0.998, and the limits of quantification for AML, VAL and HCTZ were 0.2, 50.0 and 2.0 ng/mL, respectively. The analytes were found to be stable in plasma samples over short and long term storage.

:

The developed method is rapid with a run time of 3.5 min and cost-effective since the simple sample preparation method is adopted. This method was successfully applied for the bioequivalence study of AML, VAL, and HCTZ in human plasma after administration of the fixed-dose combination tablet of (10/160/25 mg). Pharmacokinetic parameters (Cmax and AUC0-72) for AML and (Cmax, AUC0-t, AUC0-∞) for VAL and HCTZ were used for bioequivalence assessment. These were determined by noncompartmental analysis of concentration data.

Conclusion:

The result showed 90% confidence intervals (obtained by ANOVA) which were within the predefined ranges. As a consequence, this method can be successfully applied for measuring and quantifying a large number of samples.

High-throughput quantification of drugs of abuse in biofluids via 96-solid-phase microextraction-transmission mode and direct analysis in real time mass spectrometry

RATIONALE

The workload of clinical laboratories has been steadily increasing over the last few years. High-throughput (HT) sample processing allows scientists to spend more time undertaking matters of critical thinking rather than laborious sample processing. Herein we introduce a HT 96-solid-phase microextraction (SPME) transmission mode (TM) system coupled to direct analysis in real time (DART) mass spectrometry (MS).

METHODS

Model compounds (opioids) were extracted from urine and plasma samples using a 96-SPME-TM device. A standard voltage and pressure (SVP) DART source was used for all experiments. Examination of SPME-TM performance was done using high-resolution mass spectrometry (HRMS) in full scan mode (100-500 m/z), whereas quantitation of opioids was performed using triple quadrupole MS in multiple reaction monitoring mode and by using a matrix-matched internal standard correction method.

RESULTS

Thirteen points (0.5 to 200 ng mL^-1 ) were used to establish a calibration curve. Low limits of quantitation (LOQ) were obtained (0.5 to 25 ng mL^-1 ) for matrices used. Acceptable accuracy (71.4-129.4%) and repeatability (1.1-24%) were obtained for validation levels tested (0.5, 30 and 90 ng mL^-1 ). In less than 1.5 hours, 96 samples were extracted, desorbed and processed using the 96-SPME-TM system coupled to DART-MS.

CONCLUSIONS

A rapid HT method for detection of opioids in urine and plasma samples was developed. This study demonstrated that ambient ionization mass spectrometry coupled to robust sample preparation methods such as SPME-TM can rapidly and efficiently screen/quantify target analytes in a HT context.