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Ester and amide derivatives of hydroxycinnamic acids are found in black cohosh (Actaea racemosa) and other Actaea plants. These two compound groups were evaluated for authentication of black cohosh dietary supplements. The hydroxycinnamic acid esters (HCAE) were profiled by ultra-performance liquid chromatography-photodiode array detection (UPLC-PDA). The hydroxycinnamic acid amides (HCAA) were acquired simultaneously by mass spectrometry-multiple reaction monitoring (UPLC-MRM) mode. In contrast with the traditional HCAE method using 8 compounds, profiles of HCAA using only 4 feruloyl dopamine-O-hexosides was more convenient for peak by peak comparison. Partial least square discriminant analysis (PLS-DA) was applied to both HCAE and HCAA datasets. Authenticated plant samples of five Actaea species were randomly divided into training and test sets to build and validate the two PLS-DA models. Both models provided reasonable estimates for the classification of A. racemosa and other Actaea plant samples. However, HCAA model performs better in sensitivity, specificity, and accuracy. Assessment of supplement samples provided quite different results for the solid and liquid dietary supplement samples, indicating the dosage form could affect the composition of marker compounds.

A novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core–shell nanocomposite of flower-like molybdenum disulfide (MoS 2 ) nanospheres and molecularly imprinted polymers (MIPs). The MoS 2 @MIP core–shell nanocomposite was prepared via the electrodeposition of a MIP layer on the MoS 2 modified electrode, using o-phenylenediamine as the monomer and favipiravir as the template. The selective binding of target favipiravir at the MoS 2 @MIP core–shell nanocomposite produced a redox signal in a concentration dependent manner, which was used for the quantitative analysis. The preparation process of the MoS 2 @MIP core–shell nanocomposite was optimized. Under the optimal conditions, the sensor exhibited a wide linear response range of 0.01 ~ 100 nM (1.57*10 −6  ~ 1.57*10 −2  μg mL −1 ) and a low detection limit of 0.002 nM (3.14*10 −7  μg mL −1 ). Application of the sensor was demonstrated by detecting favipiravir in a minimum amount of 10 μL biological samples (urine and plasma). Satisfied results in the recovery tests indicated a high potential of favipiravir monitoring in infectious COVID-19 samples. Graphical abstract

Innovative and sustainable synchronous spectrofluorimetric techniques were developed for the simultaneous assessment of favipiravir (FVP) and levofloxacin (LEV). Some COVID-19 treatment plans call for these drugs to be given together, so reliable approaches are needed to confirm that the studied drugs are of good quality. FVP and LEV are determined with high sensitivity in the nanogram per milliliter range, with high accuracy (recoveries of 99.34% ± 1.10 and 98.87% ± 0.44, respectively). Method validation was conducted in accordance with ICH guidelines. Moreover, several metric systems (Analytical Eco-Scale, GAPI, AGREE) are used to assess environmental sustainability, which confirms the greenness of the proposed method. Also, blueness and whiteness criteria (BAGI, RGB 12) were used to check the usefulness and analytical effectiveness of the established method. As this spectrofluorimetric method is simple, rapid, and inexpensive, it is preferred over other analytical techniques for the routine analysis of the drug combination in bulk powders and pharmaceutical formulations.

In the current work, a simple, economical, accurate, and precise HPLC method with UV detection was developed to quantify Favipiravir (FVIR) in spiked human plasma using acyclovir (ACVR) as an internal standard in the COVID-19 pandemic time. Both FVIR and ACVR were well separated and resolved on the C18 column using the mobile phase blend of methanol:acetonitrile:20 mM phosphate buffer (pH 3.1) in an isocratic mode flow rate of 1 mL/min with a proportion of 30:10:60 %, v/v/v. The detector wavelength was set at 242 nm. Maximum recovery of FVIR and ACVR from plasma was obtained with dichloromethane (DCM) as extracting solvent. The calibration curve was found to be linear in the range of 3.1–60.0 µg/mL with regression coefficient (r2) = 0.9976. However, with acceptable r2, the calibration data’s heteroscedasticity was observed, which was further reduced using weighted linear regression with weighting factor 1/x. Finally, the method was validated concerning sensitivity, accuracy (Inter and Intraday’s % RE and RSD were 0.28, 0.65 and 1.00, 0.12 respectively), precision, recovery (89.99%, 89.09%, and 90.81% for LQC, MQC, and HQC, respectively), stability (% RSD for 30-day were 3.04 and 1.71 for LQC and HQC, respectively at −20 °C), and carry-over US-FDA guidance for Bioanalytical Method Validation for researchers in the COVID-19 pandemic crisis. Furthermore, there was no significant difference for selectivity when evaluated at LLOQ concentration of 3 µg/mL of FVIR and relative to the blank.

Interactions among microscopic planktonic organisms underpin the functioning of open ocean ecosystems. With few exceptions, these organisms lack advanced eyes and thus rely largely on chemical sensing to perceive their surroundings. However, few of the signaling molecules involved in interactions among marine plankton have been identified. We report a group of eight small molecules released by copepods, the most abundant zooplankton in the sea, which play a central role in food webs and biogeochemical cycles. The compounds, named copepodamides, are polar lipids connecting taurine via an amide to isoprenoid fatty acid conjugate of varying composition. The bloom-forming dinoflagellate Alexandrium minutum responds to pico- to nanomolar concentrations of copepodamides with up to a 20-fold increase in production of paralytic shellfish toxins. Different copepod species exude distinct copepodamide blends that contribute to the species-specific defensive responses observed in phytoplankton. The signaling system described here has far reaching implications for marine ecosystems by redirecting grazing pressure and facilitating the formation of large scale harmful algal blooms. Significance We report the chemical basis for a critical question in ocean science: how do single-celled algae, which are responsible for almost half of Earth's photosynthesis, sense their environment to respond appropriately to the lethal threat of predation? The increasing frequency of toxic algal blooms, with worldwide consequences to human health, fisheries, and marine ecosystem functioning, has garnered much attention in recent years, but it has remained unclear how algal toxicity is regulated. With the current paper, we show that substantial (20×) induction of toxicity occurs when one species of algae is exposed to a family of previously unknown chemical cues from predatory zooplankton (copepods). The copepodamides represent the first discovery, to our knowledge, of chemical cues mediating interactions between marine zooplankton and their prey.

Tissue pH is an indicator of altered cellular metabolism in diseases including stroke and cancer. Ischemic tissue often becomes acidic due to increased anaerobic respiration leading to irreversible cellular damage. Chemical exchange saturation transfer (CEST) effects can be used to generate pH-weighted magnetic resonance imaging (MRI) contrast, which has been used to delineate the ischemic penumbra after ischemic stroke. In the current study, a novel MRI ratiometric technique is presented to measure absolute pH using the ratio of CEST-mediated contrast from amine and amide protons: amine/amide concentration-independent detection (AACID). Effects of CEST were observed at 2.75 parts per million (p.p.m.) for amine protons and at 3.50 p.p.m. for amide protons downfield (i.e., higher frequency) from bulk water. Using numerical simulations and in vitro MRI experiments, we showed that pH measured using AACID was independent of tissue relaxation time constants, macromolecular magnetization transfer effects, protein concentration, and temperature within the physiologic range. After in vivo pH calibration using phosphorus (31P) magnetic resonance spectroscopy (31P-MRS), local acidosis is detected in mouse brain after focal permanent middle cerebral artery occlusion. In summary, our results suggest that AACID represents a noninvasive method to directly measure the spatial distribution of absolute pH in vivo using CEST MRI.

A rapid, sensitive, and selective reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous determination of five COVID-19 antiviral drugs: favipiravir, molnupiravir, nirmatrelvir, remdesivir, and ritonavir. The chromatographic separation was achieved on a Hypersil BDS C18 column (4.5 × 150 mm, 5 μm particle size) using an isocratic mobile phase consisting of water and methanol (30:70 v/v, pH 3.0 adjusted with 0.1% ortho-phosphoric acid) at a flow rate of 1 mL/min with UV detection at 230 nm. The optimized method demonstrated good chromatographic resolution with retention times of 1.23, 1.79, 2.47, 2.86, and 4.34 min for favipiravir, molnupiravir, nirmatrelvir, remdesivir, and ritonavir, respectively. The method was validated according to ICH guidelines, showing linearity in the concentration range of 10–50 µg/mL with correlation coefficients (r²) ≥ 0.9997 for all analytes. The limits of detection were 0.415–0.946 µg/mL, while the limits of quantification were 1.260–2.868 µg/mL. The method demonstrated high trueness (99.59-100.08%) and precision (RSD < 1.1%). The validated method was successfully applied to the determination of these drugs in their pharmaceutical formulations, with recovery values ranging from 99.98 to 100.7% and no significant interference from excipients. Comprehensive greenness and practicality evaluations using five assessment tools yielded favorable scores: AGREE (0.70), AGREEprep (0.59), MoGAPI (70%), BAGI (82.5), and CACI (79), indicating good environmental performance and excellent practical applicability for routine pharmaceutical quality control analysis. The multi-tool assessment confirmed the method’s environmental friendliness through strategic solvent selection and minimal sample preparation requirements, while demonstrating superior practical implementation characteristics including cost-effectiveness and accessibility in standard analytical laboratories.

The implementation of quality by design offer quality and safety product to patients, efficient processes for continuous improvements to manufacturers, negligible amount of batch failures and robust product quality attributes. This study was designed to establish a simple, specific, precise, and accurate reverse phase-high performance liquid chromatographic (RP-HPLC) method for the quantitative determination of remdesivir and favipiravir in Capsule dosage forms. The RP-HPLC method was performed on a Kromasil 100A C18 column (250 mm x 4.6 mm, 5 μm particle size) with a mobile phase containing (50 mL of acetonitrile, 350 mL methanol, 100ml of water and 0.5 mL of Phosphoric acid). The flow rate was 1.0 mL/min. The ultraviolet (UV) detection wavelength was 300 nm, and the column temperature was set at ambient. Linearity and range stock solutions were prepared as 50% to 150%. The calibration curves showed a good linear response ranged from 0.02 to 0.06 mg/ml (r=1.0000) for favipiravir and 0.022 to 0.066 mg/ml (r=1.0000) for remdesivir, and the average recoveries were 99.9% for favipiravir and 99.8% for remdesivir in assay test. The retention time of favipiravir was RT 11.5 minutes and remdesivir 20.95 minutes, tailing factor was not more than 1.5 and resolution of more than 2.0 respectively. The extended run time was supported by high concentration of favipiravir and uneven peak behavior of remdesivir in single run, which disturb resolution, retention times, injection repeatability. Reducing runtime on HPLC will lead to coelution of peaks, poor resolution, and loss of sensitivity during degradation profiling. This issue may be overcome with future UHPLC technique. The method was validated in accordance to International Council for Harmonization of Technical Requirements of Pharmaceuticals for Human Use (ICH) guidelines. The limit of detection (LOD) for Favipiravir was 0.104mg/ml and Remdesivir was 0.052mg/ml and limit of quantification (LOQ) for Favipiravir was 0.316mg/ml and Remdesivir was 0.158mg/ml respectively. In stress conditions, this product undergoes degradation and was considered sensitive to Acid, Alkali, Oxidation, reduction, hydrolysis, high temperature and humidity. The assay methods was simple, rapid, sensitive, repeatable, eco-friendly, stability indicating and can be used cost-effectively for the testing of these two drug substances in capsule dosage form. Due to the emergent need of antivirals for flu management, this coloaded combination was considered as dire need of society. Also, we reported that the product must be stored under ambient temperature, low humidity, and protected from light exposure.

Recent analyses conducted by German official food control reported detection of the aromatic amides N -(2,4-dimethylphenyl)acetamide (NDPA), N -acetoacetyl-m-xylidine (NAAX) and 3-hydroxy-2-naphthanilide (Naphthol AS) in cold water extracts from certain food contact materials made from paper or cardboard, including paper straws, paper napkins, and cupcake liners. Because aromatic amides may be cleaved to potentially genotoxic primary amines upon oral intake, these findings raise concern that transfer of NDPA, NAAX and Naphthol AS from food contact materials into food may present a risk to human health. The aim of the present work was to assess the stability of NDPA, NAAX and Naphthol AS and potential cleavage to 2,4-dimethylaniline (2,4-DMA) and aniline during simulated passage through the gastrointestinal tract using static in vitro digestion models. Using the digestion model established by the National Institute for Public Health and the Environment (RIVM, Bilthoven, NL) and a protocol recommended by the European Food Safety Authority, potential hydrolysis of the aromatic amides to the respective aromatic amines was assessed by LC–MS/MS following incubation of the aromatic amides with digestive fluid simulants. Time-dependent hydrolysis of NDPA and NAAX resulting in formation of the primary aromatic amine 2,4-DMA was consistently observed in both models. The highest rate of cleavage of NDPA and NAAX was recorded following 4 h incubation with 0.07 M HCl as gastric-juice simulant, and amounted to 0.21% and 0.053%, respectively. Incubation of Naphthol AS with digestive fluid simulants did not give rise to an increase in the concentration of aniline above the background that resulted from the presence of aniline as an impurity of the test compound. Considering the lack of evidence for aniline formation from Naphthol AS and the extremely low rate of hydrolysis of the amide bonds of NDPA and NAAX during simulated passage through the gastrointestinal tract that gives rise to only very minor amounts of the potentially mutagenic and/or carcinogenic aromatic amine 2,4-DMA, risk assessment based on assumption of 100% cleavage to the primary aromatic amines would appear to overestimate health risks related to the presence of aromatic amides in food contact materials.

Many COVID-19 sufferers have a history of cardiovascular illnesses, which makes them more likely to develop severe COVID-19. Such patients were advised by experts to prioritize drug therapies based on their doctor’s commendations to avoid exacerbating their basic illnesses. Therefore, developing an analytical methodology for the concurrent estimation of medications prescribed for co-treating cardiovascular and COVID-19 illnesses is becoming critical in both bioavailability hubs and QC units. Herein, an inventive, rapid, and affordable HPTLC approach was developed, and its conditions were optimized employing the full factorial design approach for the concurrent estimation of aspirin, atorvastatin, atenolol, losartan, remdesivir, and favipiravir as co-administered medications, either with salicylic acid or not. Using the desirability function, the experimental design approach could forecast the best eluent system for optimal resolution results. On HPTLC-silica plates, the above-mentioned medications were separated utilizing an eluent system of ethyl acetate, methylene chloride, methanol, and ammonia (6:4:4:1 by volume), and their spots were detected at 232 nm. The proposed methodology was evaluated following ICH prerequisites and applied successfully to the medications’ dosage forms, human plasma, and buffered dissolution media with superb recovery proportions and no intrusiveness from formulations’ additives or plasma matrices. Five metrics were employed to appraise the suggested technique’s greenness: AGREE, eco-scale, Raynie and Driver, GAPI, and NEMI. The sensitivity, large sample capacity, and short run duration (15 min) of the proposed methodology confirm its appositeness for regular estimation of the above-mentioned medications.