Array Detection Method Research Articles

Comprehensive quality evaluation of processed Scrophulariae Radix from different regions of China using HPLC coupled with chemometrics methods.

Scrophulariae Radix (SR) has been extensively used in traditional Chinese medicine (TCM) for thousands of years. However, the processing methods and production areas of Scrophularia ningpoensis have undergone notable historic changes. Thus, their effects on the bioactive constituents of SR still need to be studied further. This study aimed to establish an objective and comprehensive method to identify the correlation of bioactive constituents of SR with variety, place of origin and processing method for evaluating their qualities. An accurate and rapid high-performance liquid chromatography-diode array detector (HPLC-DAD) method for the simultaneous determination of 11 marker components (aucubin, harpagide, 6-O-methyl-catalpol, harpagoside, verbascoside, isoverbascoside, angoroside C, cinnamic acid, l-tyrosine, l-phenylalanine, and l-tryptophan) was established to evaluate the quality of SR for the first time. In addition, the effects of different production areas and processed methods on the target compounds were studied by analysing 66 batches of SR samples with chemometrics methods, including similarity evaluation of chromatographic fingerprints of TCM, principal component analysis (PCA), and partial least squares-discriminant analysis (PLS-DA). Compared with "sweating", short-term "steaming" and "slice-drying" could largely preserve the bioactive constituents of SR. When using the model established through PLS-DA, five components were identified as the most significant variables for discrimination. Furthermore, the score plots of PCA and the similarity evaluation revealed that variety had a more notable influence on the quality of SR than the place of origin. An objective approach of HPLC fingerprint coupled with chemometrics analysis and quantitative assessment could be applied to discriminate different processed SR and evaluate the qualities of SR rapidly.

Preparation of Bioactive De-Chlorophyll Rhein-Rich Senna alata Extract.

Senna alata leaves display various biological activities as a result of their rhein and phenolic composition. The objective of this study was to develop bioactive de-chlorophyll rhein-rich S. alata extracts. The rhein content was quantified using a validated high-performance liquid chromatography-diode array detection (HPLC-DAD) method. The best process parameters for maximizing rhein were established using ultrasound-assisted extraction (UAE). The optimal conditions for the parameters were determined using the Box-Behnken design (BBD); 95% v/v ethanol was used as the extraction solvent at 59.52 °C for 18.4 min with a solvent-to-solid ratio of 25.48:1 (mL/g) to obtain the predicted value of rhein at 10.44 mg/g extract. However, the color of the rhein-rich extract remained dark brown. For the removal of chlorophyll, liquid-liquid extraction with vegetable oils and adsorption with bleaching agents were employed. The bleaching agents were significantly more effective at removing chlorophyll and had less of an effect on the reduction in rhein content than vegetable oils. The presence of rhein and phenolics in the de-chlorophyll extracts might be responsible for their antioxidant, anti-inflammatory, and antibacterial activities. These findings indicate that rhein-rich extract and its de-chlorophyll extracts possess sufficient biological activities for the further development of cosmeceuticals and pharmaceuticals.

High signal-to-noise-ratio ultrasonic imaging of crack defects in particles filled composite explosives

<sec>Polymer bonded explosive (PBX) is a kind of composite material with highly filled molding explosive particles (normally more than 95%) and a small quantity of binders (less than 5%). The effective detection of internal cracks in PBX is of great significance in evaluating structural integrity and safety reliability.</sec><sec>Ultrasonic phased array detection and imaging methods show great advantages and potential in detecting crack defects. But acoustic test results indicate that the PBX has unique characteristics with low longitudinal wave velocity (～3000 m·s<sup>–1</sup>) and strong attenuation (attenuation coefficient ～400 dB·m<sup>–1</sup> for 2.5 MHz ultrasound). When the defect is imaged by traditional ultrasonic total focusing method (TFM), the structural noises at the boundaries between particles lead to low signal-to-noise ratio (SNR) in the FMC signals and strong background noise in reconstructed image, which will disturb the detection of cracks.</sec><sec>To realize the high SNR imaging of crack defects in PBX, an ultrasonic imaging algorithm based on baseband nonlinear synthetic focusing (BB-NSF) is proposed. By utilizing the spatial coherence of the received signals in full matrix capture (FMC) data, the pixel intensity at defect position can be enhanced while the background noise can be drastically weakened. The delay rule of the algorithm is modified according to the characteristics of PBX surface configuration. In this way, the high SNR imaging of crack defects with different orientations of PBX surface configuration is realized, and the quality of the reconstructed images is compared and evaluated quantitatively. Meanwhile, the base band transformation in calculation process optimization could significantly reduce calculation burden and increase imaging efficiency.</sec><sec>Experimental results show that the proposed algorithm can effectively suppress background noise and significantly improve the ability to detect the PBX cracks. The effective suppression to background noise makes the defect more highlighting and distinguished easily. For the BB-NSF algorithm, spatial coherence coefficient <i>p</i> is a crucial parameter used for dynamically regulating the SNR of reconstructed image. When <i>p</i> value is more than 2.0, the SNR of the ultrasonic reconstructed image of PBX crack defect is improved by more than 10 dB compared with that of the traditional linear synthetic focusing imaging. With the increase of <i>p</i> value, the SNR is further improved, while the calculation efficiency for a single image is almost kept stable. Moreover, the increase of SNR to some extent will improve the far-field detect capability.</sec><sec>Besides, with the BB-NSF algorithm, flexible transducer inhibits different imaging characteristics of for cracks with different orientations and depths in curved PBX specimens. For defects with large orientation angle and buried depth, the tip, root and shape of cracks can be completely present. For defects with small orientation angle and buried depth, part of shape and contour features will be lost.</sec><sec>In conclusion, the BB-NSF algorithm shows the advantage of high SNR and calculation efficiency in imaging PBX cracks, and exhibits great application prospect in imaging internal defects of other strongly attenuated composites.</sec>

Development and optimization of natural deep eutectic solvent-based dispersive liquid-liquid microextraction coupled with UPLC-UV for simultaneous determination of parabens in personal care products: evaluation of the eco-friendliness level of the developed method.

Dispersive liquid-liquid microextraction (DLLME) combined with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD) method has been developed and validated for the determination of parabens in personal care products. In this study, a natural deep eutectic solvent (NADES) composed of menthol and formic acid at a molar ratio of 1 : 2 was prepared and used as an extraction solvent. The influencing variables on the extraction efficiency such as extraction solvent type and volume, composition of NADES, salt addition, vortex and centrifugation time were investigated. The proposed method exhibited good linearity with determination coefficients of ≥0.9992. The relative recoveries for the studied analytes ranged from 82.19 to 102.45%. Limits of detection and limits of quantification were in the range of 0.17-0.33 ng mL-1 and 0.51-0.99 ng mL-1, respectively. To evaluate the applicability of the developed method, it was successfully applied to determine four parabens in personal care products. Additionally, the eco-friendliness level of the presented method was evaluated using Eco-Scale Assessment, Green Analytical Procedure Index and Analytical GREEnness metric. The developed method is simple, environmentally friendly and cost effective and it could be employed for determination of parabens in personal care products without harming the environment.

Ultrasonic phased array detection method for butt fusion welding defects of HDPE pipes

The welding joint is the weak link of the high-density polyethylene pipeline. The continuous development of ultrasonic phased array technology is expected to replace traditional non-destructive testing methods. In this paper, ultrasonic phased array technology is used to detect the defects of butt fusion welding. The results show that the ultrasonic phased array can distinguish between metallic and non-metallic inclusions, and the inclusion size can be displayed. Besides, insufficient fusion defects have no obvious defect features in the sector scan results. The types of insufficient fusion defects can be judged from the end-face line scan results.

Analytical Validation of a Reversed-Phase Ion Pairing HPLC-DAD Method for the Simultaneous Determination of Anthropogenic Pollutants

Caffeine, trigonelline, nicotinamide, and hippuric acid are potential organic markers of anthropogenic activities in the environment. In this work, a selective, precise, accurate, and robust reverse phase high performance liquid chromatography with a diode array detection method was developed for their simultaneous determination. Chromatographic analysis was achieved on GraceSmart RP C18 (150 mm x 4.6 mm, 5 μm) column. The mobile phase was 20 mM ammonium acetate buffer (pH 4.5) and methanol in gradient elution mode at a flow rate of 1.0 mL min-1, with 5 mM heptafluorobutyric acid as an ion pairing agent. Detection was performed at 275 nm for caffeine, 265 nm for trigonelline, 261 nm for nicotinamide, and 250 nm for hippuric acid. The method was validated as per the International Conference on Harmonization guidelines. Linear responses were found in the concentration range of 10-200 μg mL-1 with a correlation coefficient of at least 0.999. The percent relative standard deviation of intra-day precision, inter-day precision, and robustness was less than 2 %. The accuracy, expressed as percentage recovery ranged between 93.23 – 99.22%. Values for limits of detection and quantification were between 0.07-0.34 μg mL-1, and 0.21-1.04 μg mL-1, respectively. Lake samples from public parks were collected and subjected to analysis using the validated method

Comparison of Differences in Chemical Composition and Related Antioxidant Activity of Snow Lotus from Different Origins.

The snow lotus is an endangered traditional Chinese medicinal herb. Saussurea involucrata, Saussurea laniceps, and Saussurea medusa, the three main snow lotus species (five herbs and two S. involucrata cell cultures), were selected for this study. Snow lotus (XLs) was extracted using 75 % (v/v) ethanol. Two reversed phase-high performance liquid chromatography-diode array detector methods were developed and validated for the determination of 10 representative components in XLs. The antioxidant efficacy of XLs and their components was investigated using DPPH, ABTS free radical scavenging, and ROS inhibition experiments. The results showed that the IC50 for DPPH scavenging ranged from 0.06-0.29 mg/mL for XLs and from 0.13-0.63 mg/mL for ABTS, and could downregulate ROS to varying degrees. The results of the antioxidant activity showed that rutin, quercetin, and isochlorogenic acid A contributed to the antioxidant capacity of XLs. The high content and activity of the cell cultures indicate that they can serve as an effective alternative to snow lotus, thus providing a theoretical basis for the selection of herbs and cell cultures to fulfil various needs.

Simultaneous Analysis of Topotecan and Capsaicin by Micellar Liquid Chromatography

Objectives: This study aimed to develop a micellar liquid chromatography-based simultaneous estimation method for the analysis of topotecan and capsaicin. Materials and Methods: The Liquid chromatographic system consisted of the Shimadzu Prominence HPLC model (Shimadzu Corp., Kyoto, Japan) containing an LC-20AT isocratic pump, an autosampler SIL-20AC, and a diode array detector SPD-M20 A (190–800 nm) was used. The drugs were analyzed at a wavelength of 230 nm using sodium dodecyl sulfate, buffer salt (0.01 M sodium dihydrogen phosphate), and n-butanol (7%) as mobile phase. Results: The developed Micellar liquid chromatography-Photodiode Array Detection (MLC-PDA) method successfully eluted the topotecan and capsaicin with retention times of 6.2 min and 16.3, respectively. The developed method has displayed the limits of detection i.e. 0.05 and 0.98 μg/mL and limits of quantification i.e 0.08 and 1.25 μg/mL for topotecan and capsaicin, respectively. Statistical analysis further demonstrated that the developed method is linear, exact, accurate, and specific for the analysis of topotecan and capsaicin. The method was verified as per the ICH guidelines. Conclusion: The developed MLC-PDA method was found to be precise, simple, and reproducible. The developed MLC-PDA method successfully estimated the topotecan and capsaicin from the combination of drugs. Micellar chromatography is an accurate, rapid, cost-effective, and less hazardous method as compared to HPLC.

Ultra-high-performance liquid chromatography using a fused-core particle column for fast analysis of propolis phenolic compounds.

Propolis is a bee product with a complex chemicalcomposition formed by several species from different geographical origins. The complex propolis composition requires an accurate and reproducible characterization of samples to standardize the quality of the material sold to consumers. This work developed an ultra-high-performance liquid chromatography with a photodiode array detector method to analyze propolis phenolic compounds based on the two key propolis biomarkers, Artepillin C andp-Coumaric acid. This choice was made due to the complexity of the sample with the presence of several compounds. The optimized method was hyphenated with mass spectrometry detection allowing the detection of 23 different compounds. A step-by-step strategy was used to optimize temperature, flow rate, mobile phase composition, and re-equilibration time. Reverse-phase separation was achieved with a C18 fused-core column packed with the commercially available smallest particles (1.3 nm). Using a fused-core column with ultra-high-performance liquid chromatography allows highly efficient, sensitive, accurate, and reproducible determination of compounds extracted from propolis with an outstanding sample throughput and resolution. Optimized conditions permitted the separation of the compounds in 5.50 min with a total analysis time (sample-to-sample) of 6.50 min.

A Validated HPLC-Diode Array Detection Method for Therapeutic Drug Monitoring of Thiopurines in Pediatric Patients: From Bench to Bedside.

Thiopurine drugs are part of the therapeutic armamentarium for pediatric patients suffering from inflammatory bowel disease (IBD) and acute lymphoblastic leukemia (ALL). The therapeutic drug monitoring of these drugs, consisting of measurements of the thiopurine metabolites thioguanine nucleotides (TGN) and methylmercaptopurine nucleotides (MMPN) are used to optimize the effectiveness of treatment and prevent adverse effects. In this context, we developed and validated a high-performance liquid chromatography-diode array detection (HPLC-DAD) method for the simultaneous quantification of thiopurine metabolites according to the most recent International Council for Harmonisation (ICH) guidelines. The calibration curves were built in the clinically relevant range of concentrations for TGN of 300-12,000 nM and for MMPN of 3000-60,000 nM. The limit of detection and the lower limit of quantification were 100 and 300 nM for TGN and 900 and 3000 nM for MMPN, respectively. The percentage of inter-day accuracy and precision (CV%) varied between 85 and 104% and 1.6 and 13.8%. Stability was demonstrated for both of the metabolites for at least 50 days at -20 °C. The proposed HPLC-DAD method showed an appropriate selectivity, specificity, linearity, accuracy, precision and good applicability to samples from patients with IBD and ALL undergoing thiopurine treatment.

Development of a High Performance Liquid Chromatography with Diode Array Detector (HPLC-DAD) Method for Determination of Biogenic Amines in Ripened Cheeses.

Biogenic amines (BAs) are organic, basic nitrogenous compounds formed during the decarboxylation of amino acids. A method for the determination of eight biogenic amines (tryptamine, 2-phenyletylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine) in ripened cheeses was developed and validated. Cheese samples with the addition of internal standards were extracted with 0.2 M perchloric acid and pre-column derivatized with dansyl chloride at 60 °C for 15 min, purified with toluene and dried under a stream of nitrogen. The samples were analyzed using high performance liquid chromatography with diode array detector (HPLC-DAD). The method was validated with the BAs at three concentration levels: 50, 100, and 200 mg/kg, respectively. The obtained values of correlation coefficient (R2) ranged at 0.9997−0.9998 for all of compounds. The limits of detection (LOD) and quantification (LOQ) were in ranges 1.53−1.88 and 5.13−6.28 mg/kg, respectively. The recovery for all of biogenic amines ranged from 70 to 120% and the precision (RSDr) value were <20%. The validated method was applied to analysis of 35 real ripened cheese samples purchased in Poland.

A validated eco-friendly, operation-safe, and cost-effective RP-HPLC method for the determination of dodine in their pesticide dosage forms using ethanol:water as mobile phase

ABSTRACT A validated simple reverse-phase high-performance liquid chromatographic – diode array detection (HPLC–DAD) method was optimised for the analysis of dodine in their pesticide dosage forms by replacing more hazardous acetonitrile and methanol with safe ethanol. The chromatographic analysis was achieved on the Waters, Symmetry C8 column (150 mm × 4.6 mm; 5 µm) using an eco-friendly isocratic eluent; ethanol: water (containing 0.1% v/v trifluoroacetic acid) (50:50, v/v) as the mobile phase with the flow rate of 1.0 mL/minute. The detector wavelength was set at 205 nm. The method was validated as per the SANCO (Directorate-General Health and Consumer Protection) and ICH (International conference on harmonisation) guidelines. The calibration curve showed a good correlation coefficient (0.9998) over the concentration range of 20.04 to 180.34 mg/L. The method was highly precise and robust with a relative standard deviation value of less than 2%. The limit of detection (LOD) and limit of quantification (LOQ) was between 0.80 and 2.40 mg/L, respectively. The extraction recovery of the analyte ranged from 99.38% to 102.00%. Assessment results proved that our analytical method is considered an eco-friendly alternative to conventionally reported methods regarding usage of safe solvents and chemicals, a minimal amount of waste production, and a short time of analysis. Accordingly, the proposed method could be readily applied for quality control purposes as an eco-friendly, simple, and efficient analytical tool.

Discovery of conversion driven by β-glucuronidase from flavone glycoside to aglycone and application in identifying the raw Scutellariae Radix

Scutellariae Radix (SR), the dried root of Scutellaria baicalensis Georgia, is a famous Chinese materia medica that has been widely employed. Raw Scutellariae Radix (RSR), steamed Scutellariae Radix (SSR), and wine Scutellariae Radix (WSR) are adopted for use in clinical practice. Because of their easily confused appearance, they are always misused. Aiming at this problem, an ultra performance liquid chromatography coupled with photodiode array detector (UPLC-PDA) method was established to survey misuse of the RSR and the processed SR (SSR and WSR) in the market by employing baicalin (BC), wogonoside (WS), baicalein (BN), and wogonin (WN) as quality indicators. Fortunately, β -glucuronidase, which mediates conversion from flavone glycoside to aglycone, was identified in the RSR samples by the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The significant production of BN and WN was witnessed in the RSR samples, which did not occur in the SSR and WSR samples in virtue of the inactivated β -glucuronidase. Besides, the different capacities of β -glucuronidase were evaluated in the tested samples. In general, we provided the first evidence to scientifically identify RSR from SSR and WSR.

A New Ultra-Performance Liquid Chromatographic Method for the Quantification of Vitamin C in Fresh and Dried Goji Berries (Lycium barbarum L.) Cultivated in Turkey.

The potential background of the study is related to comprehensive detection of the content of vitamin C with an actual chromatographic method. Vitamin C is of vital importance in terms of human life and health due to its polyfunctional activity such as antioxidant activity and antiviral effect with other biological functions. In this regard, it may be necessary to update analytical methods or develop up-to-date analytical methods to accurately estimate the amount of vitamin C in natural samples. In this study, a new ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA) method has been developed for the determination of vitamin C content in fresh and dried goji berries (Lycium barbarum L.), which are cultivated in Turkey. The chromatographic elution of vitamin C in natural fruit samples was achieved on an ACQUITY UPLC BEH C18 (1.7 µm, 2.1 mm × 100 mm) column using methanol and 0.1 M H3PO4 pH 2.15 (20:80, v/v), which are mobile phase. UPLC determination was done at the 242.8 nm. Flow rate was 0.20 mL/min at a column temperature of 30°C. Linearity range of the calibration graph was found to be at 5-30 µg/mL. The validity of the newly developed UPLC method was tested by analyzing individual test samples and added samples. Applicability of the validated UPLC method was verified by the quantitative analysis of vitamin C content in both fresh and dried goji berries. We believe that the newly developed and validated UPLC method would be a useful and promising approach for simple quantitative analysis of goji berry samples for vitamin C. In previous studies, no UPLC-PDA method was reported for the analysis of vitamin C in goji berries. The method provided a good repeatability for the analysis of real samples.

Characterization of complex photosynthetic pigment profiles in European deciduous tree leaves by sequential extraction and reversed-phase high-performance liquid chromatography.

Leaf pigments, including chlorophylls and carotenoids, are important biochemical indicators of plant photosynthesis and photoprotection. In this study, we developed, optimized, and validated a sequential extraction and liquid chromatography-diode array detection method allowing for the simultaneous quantification of the main photosynthetic pigments, including chlorophyll a, chlorophyll b, β-carotene, lutein, neoxanthin, and the xanthophyll cycle (VAZ), as well as the characterization of plant pigment derivatives. Chromatographic separation was accomplished with the newest generation of core–shell columns revealing numerous pigment derivatives. The sequential extraction allowed for a better recovery of the main pigments (+25 % chlorophyll a, +30 % chlorophyll b, +42 % β-carotene, and 61% xanthophylls), and the characterization of ca. 5.3 times more pigment derivatives (i.e., up to 62 chlorophyll and carotenoid derivatives including isomers) than with a single-step extraction. A broad working range of concentrations (300–2,000 ng.mL−1) was achieved for most pigments and their derivatives and the limit of detection was as low as a few nanograms per milliliter. The method also showed adequate trueness (RSD < 1%) and intermediate precision (RSD < 5%). The method was developed and validated with spinach leaves and their extracts. The method was successfully performed on leaf pigment extracts of European deciduous tree species. Within a case study using Fagus sylvatica L. leaves, pigment derivatives revealed a high within-individual tree variability throughout the growing season that could not be detected using the main photosynthetic pigments alone, eventually showing that the method allowed for the monitoring of pigment dynamics at unprecedented detail.

Determination of nitroimidazole antibiotics based on dispersive solid-phase extraction combined with capillary electrophoresis.

For a long time, the detection of nitroimidazole antibiotics (NIABs) has been a research focus in environmental analytical chemistry. In this work, a novel technique for the analysis of nitroimidazoles was established based on capillary electrophoresis (CE). UiO-66, synthesized using a solvothermal method, was utilized as an adsorbent in the dispersive solid-phase extraction (DSPE) of five different NIABs. The separation and detection of NIABs in environmental water samples were accomplished using the CE diode array detection method. The optimal extraction conditions were obtained after systematically studying the effects of adsorption time, the amount of extractant, and elution solvent on extraction efficiency. According to the results of the study, the limit of detections of the five NIABs were between 16 and 97ng/mL, the relative standard deviations were between 0.32% and 0.55%, and the spike recoveries were between 87.43% and 104.8%. This study presents a novel technique for measuring NIABs in complex water samples.

Polyphenols in Different Plant Parts of Inula grandiflora Collected from Two Habitats of Uttarakhand Himalayas

ABSTRACT The phytoconstituent analyses have been undertaken for the first time from the different plant parts of Inula grandiflora Willd. collected from two habitats (open dry slopes and moist places) of Govind Pashu Vihar National Park and Wildlife Sanctuary, Uttarakhand, India. The total phenolic and flavonoid contents and antioxidant activity have been estimated from the methanolic extracts. Ten phenols and five flavonoids were quantified in the different parts using High Performance Liquid Chromatography-Photodiode Array Detection (HPLC-PDA) method. Among the plant parts, the trend of accumulation of total phenols and flavonoids was as follows: roots > flowers > stems > leaves in both populations. It has been observed that Kalkati Dhar germplasm has the highest phenolic content in the roots (16.42 ± 0.12 mg g−1 DW), while accession collected from Renugaad has the highest flavonoid content in the flowers (4.34 ± 0.024 mg g−1 DW). Eight bioactive compounds (caffeic acid, resorcinol, p-coumaric acid, ferulic acid, veratric acid, myristicin, coumarin, and quercetin) were found dominant in the Kalkati Dhar germplasm (3200 m asl, high altitude). Significantly, seven compounds, viz; vanillic acid, vanillin, cinnamic acid, epicatechin, catechol, luteolin, and rutin, were found predominate in the Renugaad germplasm (2750 m asl, low altitude). Overall, root part accumulates most of the bioactive polyphenolic compounds as compared to the aerial parts; therefore, it has the highest antioxidant potential.

A Validated HPLC Multichannel DAD Method for the Simultaneous Determination of Amoxicillin and Doxycycline in Pharmaceutical Formulations and Wastewater Samples

The quality of marketed pharmaceutical formulations must be guaranteed to attain better remedial effects and lower toxicity. The wide exploitation of antibiotics may lead to their presence as residues in body fluids and wastewaters, potentially toxic to human health. Consequently, determining antibiotics in pharmaceutical formulations and water samples is of significant importance. This paper aims to explore the possibilities of a high-performance liquid chromatography coupled with diode array detection (HPLC-DAD) method to obtain a simple, fast, and efficient analytical tool for the simultaneous determination of antibiotics in pharmaceutical formulations and environmental samples. The method was completely validated with regard to specificity, linearity, detection and quantification limits, precision, accuracy, and robustness according to the requirements of existing guidelines, and was proven to be reliable and suitable for the envisioned application. The linearity study was conducted for the calibration curves in the range of 10–100 μg/mL. The limits of detection and quantification were found to be 0.2 and 0.7 μg/mL for amoxicillin and 0.3 and 1.0 μg/mL for doxycycline, respectively. The high recovery of drugs from their commercial pharmaceutical formulations (93%) and from wastewater samples (98%) indicated good accuracy and precision. The method is robust for small or deliberate changes to the chromatographic parameters, and it was successfully applied for the quantitative determination of amoxicillin and doxycycline in wastewater and commercial tablets. The obtained results proved that the validated method is appropriate for its intended use in the routine quality control and assay of both antibiotics studied.

Integrating pharmacokinetics and network analysis to investigate the mechanism of Moutan Cortex in blood-heat and blood stasis syndrome

BackgroundRaw Moutan Cortex (RMC) has been used in China and other Asian countries for thousands of years. Its medical application is the treatment of cooling blood and promoting blood circulation. However, its therapeutic mechanism is still undefined.MethodsIn this study, the pharmacokinetics strategy that integrated network analysis was employed to explore the mechanism of RMC in blood-heat and blood stasis syndrome (BHS) model rats. Firstly, Ultra-High performance Liquid Chromatography coupled with Diode Array Detector (UHPLC-DAD) method was developed to determine nine absorbed compounds in rat serum in BHS and normal rats after oral administration of RMC extract respectively. Then the pharmacology network was established based on the relationship between nine compounds absorbed into the blood and BHS targets. Finally, the predicted hub targets were validated experimentally in human umbilical vein endothelial cells (HUVECs).ResultsPharmacokinetic study showed that the pharmacokinetic parameters of nine absorbed compounds had significant differences between BHS and normal groups (p < 0.05). Network analysis showed that 8 target genes, namely, F2, F10, F7, PLAU, MAPK14, MAPK10, AKT1, and NOS3 may be the primary targets regulated by RMC for the treatment of BHS. Among them, targets (F2, F10, F7 and MAPK14, MAPK10, AKT) and 4 active ingredients (paeonol, paeoniflorin, quercetin and oxypaeoniflorin) were selected for evaluating the reliability in vitro experiments, which revealed that the mechanism of RMC against BHS syndrome may inhibit inflammatory pathways and regulate coagulation cascades pathway for cooling and promoting blood circulation.ConclusionThe proposed pharmacokinetics study integrated network analysis strategy provides a combination method to explore the therapeutic mechanism of RMC on BHS.Graphical

Content and stability of B complex vitamins in commercial cosmetic products.

Individual B vitamins have many favorable effects on the skin and are common cosmetic ingredients. However, their formulation is demanding due to stability issues, which consequently affect the products' quality. We aimed to determine the quality (labeling accuracy, content determination, and content-related quality control) and stability under long-term and accelerated storage conditions of a representative sample of commercial cosmetics containing the most common B vitamins - nicotinamide, dexpanthenol, pyridoxine, and cyanocobalamin. Cyanocobalamin was determined by a previously published stability-indicating HPLC- diode array detector (DAD) method for the simultaneous determination of all hydrophilic vitamins. This method was additionally simplified and adjusted for the time-effective analysis of nicotinamide, dexpanthenol, and pyridoxine. Both methods were properly validated. All labeled B vitamins were present in the 36 tested products, mostly in contents, reported effective on the skin. Thus, a straightforward correlation between vitamin contents and product prices were not observed. The content-related quality control of eight products, which quantitively specify their content, revealed significantly lower nicotinamide contents (47% and 57%) in two products and appropriate or higher nicotinamide (102%-112%) and dexpanthenol (100%-104%) contents than declared in the remaining products. The 6-month long-term and accelerated stability studies demonstrated the products' physical stability, but also revealed dexpanthenol, pyridoxine, and cyanocobalamin degradation, while nicotinamide was mostly stable in the tested products. The obtained results provide an inside into the quality of commercial vitamin B cosmetics and highlight the importance of stability testing in the formulation of quality, efficient, and safe cosmetics.