Repeatability RSD Research Articles

High-performance liquid chromatography determination of polyamine contents in poultry based on precolumn benzoyl chloride derivatization

Polyamines are widely present in animal cells and perform important physiological and biochemical functions. Moderate intake of polyamines contributes to good health. Poultry is one of the common sources of polyamines in daily life. However, different tissues from poultry contain different amounts of polyamine. In this study, an efficient and accurate method for the determination of polyamines was developed by high-performance liquid chromatography (HPLC) with precolumn benzoyl chloride derivatization. The linearity of the polyamines was good between 10–400 nmol/mL, with the limit of detection (LOD, S/N = 3) and limits of quantification (LOQ, S/N = 10) were 0.37 and 1.23 nmol/mL. The recoveries of the method ranged from 94.73 % to 106.58 % with high accuracy (RSD < 7 %) and no significant matrix effects or interferences. The RSD of intra-day, inter-day and inter-batch repeatability in the range of 0.07–1.57 %, 0.08–1.03 % and 1.46–4.57 %. The method was successfully used to detect polyamines in poultry tissue, with putrescine, spermidine and spermine levels ranging from 3.24 to 29.85 mg/kg, 0.46 to 164.11 mg/kg and 63.39 to 489.57 mg/kg, respectively. Polyamine levels were higher in the spleen, thymus and bursa of fabricius and lower in the heart and muscle. Furthermore, the method was employed to study the effect of exogenous spermine on polyamine deposition in different tissues of geese. In summary, the method is suitable for the detection of polyamine in animal tissues.

Method validation of an inductive measurement system (IMS) for nanoscale zero-valent iron (nZVI) particles determination in sand-packed columns

The purpose of this work was to develop and validate a rapid, non-destructive, real-time measurement system for nanoscale zero-valent iron (nZVI) particles determination in sand-packed columns. This aims to provide an approach to analyse for nZVI particle transport and nZVI induced contaminant degradation reactions in 1-dimensional aquifer experiments. The inductive measurement system (IMS) was developed and tested by measuring columns filled with varying portions of nZVI and sandy aquifer material. Method validation was conducted for this innovative approach in accordance with several guidelines in disciplinary areas. The linearity of ZVI concentration and measurement signal was confirmed. Calibration curves were determined to be linear over the range of 0.11–53.50 g/L for nZVI NANOFER STAR, 0.10–81.67 g/L for nZVI BASF 1, 0.12–58.26 g/L for nZVI Carbo-Iron, 0.12–69.70 g/L for nZVI NANOFER 25DS ORM, 0.12–50.69 g/L for nZVI NANOFER 25DS, and 0.21–1613.39 g/L for nZVI Höganäs 1* (dry). This method was determined to be sensitive in nZVI, accurate (101.63 % within-run recovery, 101.85 % between-run recovery covering 76 days), and precise (0.46 % repeatability RSD, 0.85 % intermediate precision RSD covering 76 days). LOQ was determined ranging from 0.10 to 0.21 g/L for nZVI used in experiments and regression through origins was selected as the calibration model. Quality control processes were performed to assure the reliability of the results and the long-term stability. Additional data processing steps allowed to compensate for measurement deviations resulting from different liquid phase compositions, e.g. dispersants used for nZVI suspensions. This method is now successfully validated in single-laboratory conditions.

Application of Iron Oxide Nanoparticles in the Surface-Assisted Laser Desorption and Ionization–Mass Spectrometry of Small-Molecule Compounds

Iron oxide nanoparticles were applied to the surface-assisted laser desorption and ionization–mass spectrometry (SALDI–MS) of small-molecule compounds, such as oligosaccharides, phytohormones, flavonoids, triglycerides, phospholipids, and amino acids. The spatial distribution of small-molecule compounds in soybean was further studied by using imaging mass spectrometry. After different preparation methods were compared, iron oxide nanoparticles calcined at 300 °C were selected. Results showed that in SALDI–MS analysis, iron oxide nanoparticles were characterized by good stability and low background noise. Analysis was performed in the positive ion mode at the laser energy of 70% with the average spectrum accumulated 30 times. The results showed that iron oxide nanoparticles had good repeatability and sensitivity in the analysis of the abovementioned small-molecule compounds. Four samples, namely, sucrose, abscisic acid, DL-aspartic acid, and 1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine, were analyzed via SALDI–MS. The spot-to-spot repeatability RSD was less than 2.8%, and the interpoint repeatability RSD was less than 5.2%. The linear correlation coefficient of the four samples was R2 &gt; 0.993 within the concentration range of 0.05–1.0 mg/mL. On the basis of these results, the distribution of small-molecule components in soybean cotyledon, radicle, and germ was analyzed through SALDI–MSI.

Rapid determination of 10 fat-soluble vitamins in health foods by ultra performance convergence chromatography

Fat-soluble vitamins are important efficacy indicators in health foods because they are essential for human physiological functions. The existing method for the simultaneous determination of fat-soluble vitamins has various problems, such as limited determination components, complex sample, pretreatment process, and high requirements for personnel operating ability. Therefore, establishing a fast, simple, and accurate method that can detect various common fat-soluble vitamins at the same time is necessary. In this study, a method for the simultaneous determination of 10 commonly used fat-soluble vitamins such as vitamin A acetate (VA acetate), vitamin A palmitate (VA palmitate), vitamin E acetate (VE acetate), vitamin K1 (VK1), α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, vitamin D2(VD2) and vitamin D3 (VD3) in health foods was established by ultra performance convergence chromatography (UPC2). First, the contents of about 1.0 g of capsule samples were accurately weighed. A grinder was used to grind tablet samples into powder. The powder mixture was then precisely weighed at 2.0 g. Both substances were placed in 50 mL brown stopper tubes. The test tube was then filled with 20 mL 75% dimethylsulfoxide (DMSO) aqueous solution for demulsification. The tubes were then sonicated before being extracted with n-hexane. The centrifuged supernatant was added to vials for detection. Viridis HSS C18 SB column (100 mm×3.0 mm, 1.8 μm) was applied and CO2 was used as the mobile phase A. After comparing the influence of acetonitrile, methanol, and their mixture on chromatographic peak separation, acetonitrile-methanol (85∶15, v/v) was used as the mobile phase B. The injection volume was 1 μL. Using simulator software, the optimal chromatographic conditions were obtained after a set of three-factor orthogonal experiments of flow rate, gradient slope, and column temperature. The flow rate and column temperature were both set at 1.9 mL/min and 30 ℃. Furthermore, the maximum absorption wavelength of these 10 fat-soluble vitamins was selected for detection. Ten vitamins were baseline separated after 7 min of gradient elution. The limits of detection (LODs) and quantification (LOQs) of capsule samples were 0.4-60 μg/g and 2-150 μg/g, respectively, whereas the results for tablet samples were 0.2-30 μg/g and 0.8-75 μg/g. The linear ranges of the 10 fat-soluble vitamins were 0.1-100 μg/mL. The recoveries of spiked samples ranged from 96.5% to 113.9%, with RSD values less than 4%. Precision, stability, and repeatability RSD values were all less than 2%. By comparison, the determination results of this method were basically consistent with the existing national food safety standards. This method is simple, rapid, sensitive, and accurate, and it can meet the detection requirements of the 10 fat-soluble vitamins in health foods. Simultaneously, this method lays the foundation for the rapid and simultaneous detection of fat-soluble vitamins in existing health foods.

Stability Indicating RP-HPLC-DAD Method For Simultaneous Estimation of Atorvastatin Calcium and Teneligliptin Hydrobromide Hydrate in Synthetic Mixture

RP-HPLC stability indicating specific, precise, accurate, cost-effective and isocratic method was developed and validated for quantitative analysis of Atorvastatin calcium and Teneligliptin hydrobromide hydrate in synthetic mixture with presence of its degradants. Separation was achieved by using Gemini, C18, using mobile phase composition [Methanol: 20 mM Ammonium acetate (70:30 v/v)] using a flow rate of 1.0 ml/min, injection volume 10µl with UV detection at 245 nm. Atorvastatin calcium and Teneligliptin hydrobromide hydrate were eluted with retention time 7.47min and 4.74min respectively. This method was validated as per ICH guideline Q2(R1). The calibration plots were over the concentration range of 10-100 μg/ml and 5-50 μg/ml for Atorvastatin calcium and Teneligliptin hydrobromide hydrate with correlation coefficient 1 and 0.9999 respectively. Percentage recovery was obtained between 98.00-100.51 % and 98.90-100.7 % for Atorvastatin calcium and Teneligliptin hydrobromide hydrate respectively. In case of Precision, Repeatability and Robustness RSD should be found less than 2. LOD were found to be 1.22 μg/ml and 0.54 μg/ml and LOQ were found to be 3.70 μg/ml and 1.64 μg/ml for Atorvastatin calcium and Teneligliptin hydrobromide hydrate respectively. The results showed that the developed method is appropriate for the routine analysis of Atorvastatin calcium and Teneligliptin hydrobromide hydrate in a synthetic mixture in presence of its degradants.

Effect of oximation reagents on gas chromatographic separation of eight different kinds of mono- and di-saccharides

The objective of this study was to investigate the effect of oximation reagents in simultaneous analysis of mono and di-saccharides using gas chromatography. Sugar oximation with O-ethylhydroxylamine separated all the mono- and di-saccharides while hydroxylamine and O-benzylhydroxylamine could make most of the saccharides separable except for xylose and arabinose. Resolution of xylose: arabinose, galactose: glucose, and fructose: galactose oximated by O-ethylhydroxylamine in DB-1ms column were 1.66, 2.15, and 6.19, respectively, which were above 1.5 and were officially acceptable for quantitative analysis according to the AOAC guideline. The applied method was then verified by the method validation parameters; LOD (0.011–0.02 mg/100 g), LOQ (0.032–0.061 mg/100 g), linearity (R2 = 0.9991–1.0000) and precision (repeatability RSD: 1.4–3.3%, reproducibility RSD: 1.7–7.6%). The greatest amounts of xylose (19.03 ± 0.38 mg/100 g), maltose (6,274.48 ± 173.59 mg/100 g) were found in the oyster sauce, and the contents of glucose (10,565.00 ± 125.31 mg/100 g), galactose (170.40 ± 4.62 mg/100 g) were greatest in soybean paste.

Simultaneous Estimation of Bilastine and Montelukast in Bulk by Rp-hplc and Assessment of Its Applicability in Marketed Tablet Dosage Form

Aim: This study proposes to develop and validate the RP-HPLC method for Bilastine and Montelukast and to substantiate the RP-HPLC analysis bestowing to ICH validation guideline Q2R1.&#x0D; Place and Duration of Study: Y. B. Chavan College of Pharmacy, Aurangabad, MS, India, between January 2020 and October 2021.&#x0D; Methodology: The mixture of drugs was subjected to optimization by trial runs with different chromatographic parameters, viz. flow rate, λ in nm, etc. The system suitability was performed by repeated injections of Bilastine (200µg/mL) and Montelukast (200µg/mL) to confirm the optimization. Furthermore, the demonstrated method was validated as per ICH Q2R1 recommendations for parameters like accuracy, precision, robustness, the limit of detection and quantitation, etc.&#x0D; Results: The outcomes of the method in terms of percent relative standard deviation (%RSD) of retention time (RT) and mean peak area were seen as 0.09, 0.35, and 0.35, 0.56 for Bilastine and Montelukast, respectively. The method was successful in achieving the qualifying criteria entrusted to ICH guidelines. The correlation coefficient, slope, and y-intercept were illustrated to be 0.9971, 17595, 217883, 0.998, 35458, and 17147, correspondingly for Bilastine and Montelukast, respectively. The range was seen in the order of 160-260µg/mL and 80-130µg/mL for Bilastine and Montelukast. The precision of the method was established with %RSD of repeatability and intermediate precision was &lt; 2 at three standard levels across the range. The %accuracy of the method was observed in the range of 96.95-101.41 %w/w and 97.37-101.89 %w/w in the order for Bilastine and Montelukast. The robustness of the method displayed the results within the prescribed boundaries. The recovered amount of Bilastine and Montelukast by spike method was observed to be 96.37-98.88 %w/w and 96.11-100.06%w/w.&#x0D; Conclusion: The author has accomplished the predefined goals by successful development and validation of the RP-HPLC method for the quantification of Bilastine and Montelukast as per ICH Q2R1 guidelines.

Development and validation of an analytical method to ensure quality requirements of hydrolysed proteins intended for agricultural use as biostimulants

Plant biostimulants, as defined by EU Reg.1009/2019, represent a promising solution to increase agricultural production, improving the efficiency of fertilizers and thus reducing their environmental impact. At present, protein hydrolysates are considered the main class of biostimulants as they increase yield and product quality of various crops. Several sources of proteins are used to produce protein hydrolysates, but in this context of environmental protection and green economy, the development of biostimulants from industry by-products is of great interest. Industry by-products of animal origin (ABPs) are classified into three categories based on the degree of risk for animal, human and environmental health, according to EU Reg. 1069/2009. In particular, tanneries are known to produce large quantities of Category 3 ABPs, which are associated with no health risk. According to EU Reg. 142/2011, ruminant proteins derived from ABPs Category 3 must be hydrolysed to a molecular weight below 10.000 Daltons (Da). This research aims to set up and validate an analytical method for a reliable determination of the high limit molecular weight of hydrolysed proteins derived from Category 3 ABPs. A gel filtration chromatography method was developed and validated by evaluation of linearity, repeatability, reproducibility (intermediate precision) and measurement uncertainty. The validation process was carried out according to Eurachem and ISO guidelines and performance characteristics were further verified by testing the method in a second and independent laboratory. Acceptance criteria of linearity R2>0.990, repeatability RSD%≤5, intermediate repeatability RSD%≤10 and uncertainty measurement U ≤ 20% were met. Therefore, the method was considered suitable to assess the compliance of the hydrolysed proteins to 10.000 Da limit in biostimulants from animal by-products.

HPLC quantitative analysis of protocatechuic acid contents in 11 Phellinus mushroom species collected in Thailand

Phellinus mushrooms have been traditionally used for various medicinal purposes. Protocatechuic acid, which was previously reported to be a component in some Phellinus mushrooms, has some pharmacological effects. This study aimed to validate a HPLC method for the quantitative analysis of the protocatechuic acid contents in the extracts from different Phellinus mushroom species collected in Thailand. HPLC was carried out using a C18 column and the gradient mobile phases of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Method validation was performed to assure the linearity, accuracy, precision, limit of detection and limit of quantitation of the analytical method. The linearity range of protocatechuic acid was 1 - 10 µg/ml. The average recovery was 104.16%. The method was shown to be precise with the RSD of repeatability and intermediate precision at less than 3%. The protocatechuic contents in 11 Phellinus mushrooms were in the range of less than 0.0099 - 0.4121 %w/w of the extract. The developed HPLC method was reliable and suitable for the quantitative analysis of protocatechuic acid content in Phellinus mushrooms.

The Development and the Validation of a Novel Dissolution Method of Favipiravir Film-Coated Tablets

The aim of this study was to develop and validate a dissolution test for favipiravir release in a tablet dosage form using ultra-high performance liquid chromatography (UHPLC). The dissolution method was developed by testing the solubility of favipiravir in media with different pH values. The results demonstrated that the best dissolution was achieved in phosphate buffer with a pH of 6.8. The amount of favipiravir that was released was about 100% after 30 min. The UHPLC method presented linearity (R = 1.000) in the concentration range of 0.044–0.44 mg/mL. The recovery parameter that was achieved ranged from 102.5% to 104.2%. The system suitability, repeatability, and intermediate precision RSD% results were found to be 0.36%, 1.99%, and 2.49%, respectively. In addition to these parameters and results, an F-test was performed using the Minitab 18 Statistical Software program for the intermediate precision and repeatability results. The standard and sample solutions were found to be stable for 2 days in their respective dissolution medium. This analytical method was also found to be selective for favipiravir. In conclusion, a simple and feasible dissolution method with a short run time of 2.5 min was developed and validated successfully. The obtained results demonstrated that the dissolution test developed here is adequate for its purpose and can be applied as the dissolution method for favipiravir in film-coated tablets for release analyses.

Development of an Analytical Method for Simultaneous Determinationof Quinolones and Tetracyclines in Livestock and Fishery Products

In this study, we developed an analytical method for simultaneous determination of 14 quinolones and 4 tetracyclines in livestock and fishery products using LC-MS/MS. The analytes were extracted from food samples with citrate buffer (containing EDTA)-methanol-acetonitrile (3 : 1 : 1, v/v/v) in the presence of n-hexane, and the extract was purified with an Oasis PRiME HLB cartridge column. It was suggested that this analytical method can also extract analytes from solid samples containing fat by using n-hexane. In addition, using methanol-acetonitrile (3 : 7, v/v) containing 0.1 vol% formic acid as an eluent from the cartridge column, the purification effect could be improved, while minimizing the impairment of the recovery rate. As a result of the validation using six types of food samples, trueness (accuracy) was 70.6%-113.8%, the RSD of repeatability was 9.0% or less, and the RSD of within-laboratory reproducibility was 15.5% or less. Using this approach, the standard values mentioned in the Japanese guideline were successfully met.

UV Spectrophotometric Methods to Quantify Alogliptin Benzoate and Pioglitazone Hydrochloride

Three new, precise, accurate and sensitive UV-Spectrophotometric methods namely Ratio Difference Spectroscopic Method (RDSM), First Derivative of Ratio Spectra Method (DR1) and Area Under Curve Method (AUC) were developed and validated for simultaneous assessment of alogliptin benzoate (ALO) and pioglitazone hydrochloride (PIO) in tablet dosage form. In RDSM, ratio spectra of both the drugs were recorded by dividing the mixtures using interfering drug as divisor. Then the difference between the amplitudes of obtained ratio spectra was measured at 288 and 291 nm for ALO and 236 and 245 nm for PIO. The second method DR1, where the first derivative of ratio spectra of both the drugs were recorded and the first derivative signal was measured at 290 nm for ALO and 276.8 nm for PIO. The scaling factor was fixed as 1 and wavelength interval (Δλ) as 2 for recording the first derivative of ratio spectra. In the third method (AUC), peak area of recorded zero order spectra was measured at 276 ± 10 nm for ALO and 267.8 ± 10 nm for PIO. All three proposed methods were validated according to “International Conference on Harmonization” (ICH) guidelines parameters. For all three methods, ALO and PIO obeyed Beer’s law in the range of 0.5-5 &amp; 1.8-18 µg/ml, respectively. The % RSD of repeatability of measurement, intra-day and inter-day precision were found to be less than 2 for all three methods. Limit of detection (LOD) and Limit of quantification (LOQ) of the drugs were calculated which proved the sensitivity of the methods. The accuracy ranged between 98-101% for all three methods. No interference from pharmaceutical excipients present in the formulation was observed. These proposed methods were found to be simple, sensitive, accurate and precise and can be applied to the simultaneous estimation of ALO and PIO in combined tablet formulation and also appropriate for routine quality control analysis.

Implementing Analytical Quality by Design (AQbD) Approach for Simultaneous Estimation of Tadalafil and Macitentan by RP-HPLC Method

The principle motive behind this work is to develop robust, low cost, and regulatory flexible method for Tadalafil and Macitentan by RP-HPLC using Analytical Quality by Design principles. Failure Mode and Effects Analysis was performed and the risk priority number was calculated, from this analysis independent variables were selected. Optimization of chromatographic condition was performed using Central Composite Design. The separation was achieved using phenomex gemini C18 (150 mm, 4.6 mm, 5μm) column using mobile phase as methanol: 10 mM ammonium formate (74.1 : 25.9 % v/v) (pH: 6.8) at a flow rate 0.94 ml/ min with detection wavelength at 260 nm and 40°C column oven temperature. This method was validated according to ICH Q2 (R1) guideline. Analytical Quality by Design method was numerically optimized with a desirability of 1.0. ANOVA result shows that model was significant for all responses. The method was found to be linear in the range of 0.1-25 μg/ml for Macitentan and 0.4-100 μg/ml for Tadalafil. Percentage recovery was found in the range of 98.6-101.7 % for Macitentan and 98.8-101.8 % for Tadalafil. The RSD of precision and repeatability was found beneath 1 %. AQbD driven method can be highly suitable for analysis of Tadalafil and Macitentan without interference.

Establishment and Validation of an ICP-MS Method for Simultaneous Measurement of 24 Elemental Impurities in Ubenimex APIs According to USP/ICH guidelines

Background: To control the potential presence of heavy metals in pharmaceuticals, the United States Pharmacopeia (USP) and International Conference on Harmonization (ICH) have put forth new requirements and guidelines. USP &lt;232&gt; and ICH Q3D specify 24 elemental impurities and their concentration limits in consideration of the permitted daily exposure (PDE) of different drug categories (oral, parenteral and inhalation). while USP &lt;233&gt; describes more information about sample preparation and method validation procedure. Objective: To establish and verify an ICP-MS method for the determination of 24 elemental impurities (Cd, Pb, As, Hg, Co, V, Ni, Tl, Au, Pd, Ir, Os, Ph, Ru, Se, Ag, Pt, Li, Sb, Ba, Mo, Cu, Sn, Cr) in ubenimex APIs according to USP/ICH guidelines. Method: Samples were analyzed by ICP-MS after direct dissolution in diluted acid solution. All elements were detected in He/HEHe mode (except for Li, which was in No gas mode). Results: The spiked recoveries were within 80-120% except Hg (79.4% at 0.5J level in HEHe mode) and Cd (121.9% at 0.5J level in HE mode). The RSD of repeatability (N = 6) for all elements were &lt; 7.0% and intermediate precision (N = 12) were &lt; 9.0%. The correlation coefficients of linear (R) for 24 elements were all &gt; 0.998. The limits of detection (LOD) were &lt; 1 ng/mL except that Ni was 1.23 ng/mL in HEHe mode. The contents of 24 elements in 3 batches of samples were significantly lower than the actual target limit of ICH, while the highest content of Pd did not exceed 10 μg/g. Conclusion: The established method was proved to be simple, sensitive and accurate. It successfully applied to the elemental impurity determination in 3 batches of ubenimex APIs from different manufactories. This method also provided technical guidance for determination of multiple elements in pharmaceutical products.

Development and optimization of a quantitative analysis of main odorants causing off flavours in cork stoppers using headspace solid-phase microextraction gas chromatography tandem mass spectrometry.

A simple and sensitive method was developed and validated to simultaneously separate and determine the 2-Methoxy-3,5-dimethylpyrazine, 2-Isopropyl-3-methoxypyrazine, guaiacol, 2-Isobutyl-3-methoxypyrazine, 2-Methylisoborneol, geosmin, 2,4,6-Trichloroanisole, 2,3,4,6-Tetrachloroanisole, 2,4,6-Tribromoanisole and Pentachloroanisole in cork stoppers via headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography tandem mass spectrometry (GC-MS/MS). The influence of the fibre coating used, the extraction times and temperatures, the sodium chloride additions and the desorption temperatures were investigated. Once done, the optimial HS-SPME conditions established were divinylbenzene/carboxenpolydimethylsiloxane/polydimethylsiloxane (DVB/CAR/PDMS) fibres, a 50°C extraction temperature, 60-min extraction time, an ionic strength of 3-g sodium chlorid and a 290°C desorption temperature. The method showed a good linearity (R2 ≥ 0.994) within the tested range (from 0.1 to 50 ng L-1 ) for all the compounds. Using TCA-d10 and MIB-d3 as internal standards the precision, expressed as repeatability and reproducibility RSD, was <10% in both. Note that the limits of quantifications (LOQs) are below the sensory threshold levels for such compounds in water and wine. Good recoveries were obtained for cork macerates (from 100.4% to 126%) and when compared with other reported methods using HS-SPME in water and cork stopper samples, the present method had more analytes with the lowest limit of detection for most of the targeted compounds, along with good precision and recovery.

Evaluation of physicochemical stability and degradation kinetics of bedaquiline in hydrolytic solutions of different pH

BackgroundTuberculosis is an infection that has high mortality rate in human as well as in animals if it remains unattained for long time. Scientists are always desirous to discover new molecules against Mycobacterium tuberculosis; one of them is bedaquiline which was recently approved to treat multidrug resistance TB. During the clinical study of new molecule stability and impurity are the key aspects to develop formulation. Stability issues in bulk drug are dangerous to drug safety and needs careful attention in formulation development. Bedaquiline stability study was completed with reversed-phase high-performance liquid chromatography (HPLC) and utilized in degradation kinetic study of bedaquiline in aqueous condition under different pH, temperature, and concentrations of degradant.ResultsLinearity was obtained in 50.0-250.0μg/ml, correlation coefficient, and regression line equation were 0.998 and Y=18528x + 7E+06 respectively. Intraday, inter day precision, and repeatability RSD were less than 2.0%. Average recovery in accuracy study was more than 98.0% showed that good recovery was obtained. Degradation kinetics parameters like activation energy (Ea), half-life (t50), rate constant (k), and shelf life (t90) were calculated under different condition for bedaquiline. Entropy and enthalpy of reaction was studied to gather knowledge about energy of system.ConclusionThe result explained that bedaquiline degradation was pH-dependant, as increase in concentration of degradant and temperature, there was increase in degradation rate of bedaquiline. Bedaquiline was stable in neutral aqueous condition and at lower temperatures, shows that drug is hydrophobic in nature. Kinetic data showed that bedaquiline followed first order kinetics in acidic and alkaline pH.

HPLC Method for the Determination Content of 5-HMF in Zishen Yutai Pill

Objective: During the preparation of Zishen Yutai Pills, 5-Hydroxymethylfurfural may be used. To establish a HPLC method for determination of 5-HMF in Zishen Yutai pill and to provide the potential quality control standard of it. Methods: RP-HPLC method was applied with the chromatographic condition as follows: the chromatographic column was Phenomenex Gemini C18 column (250×4.6mm, 5μm), methanol-water (10:90) as the mobile phrase, the flow rate was 0.8mL/min, the detection wavelength was 284nm, the column temperature was 30°C, and the injection volume was 10μL. Results: The calibration curve was linear in the range of 2.16~43.27μg. mL^-1 for 5-HMF (r²=0.9993). The RSD of the method repeatability was 0.97% (n=6) and the average recovery was 99.4% (RSD=0.58%). What’s more, the specificity, precision and stability results were also good. Conclusion: The method for HPLC is not only sensitive and accurate. It is also easy to operate which can be used as the determination method for 5-HMF and has a guiding role for the quality control of the Zishen Yutai pill.

Simultaneous determination of acetaldehyde, ethyl acetate, methanol, iso butanol, and iso almyacol concentrations in white alcol in some areas in Hai Duong province in 2018 - 2019

The research has developed a method for simultaneous determination of acetaldehyde, ethyl acetate, methanol, isobutyl alcohol, isoamyl alcohol in white alcohol. Validation results show that the method has satisfactory accuracy with recovery in the range of 105 - 108%, repeatability RSD &amp;lt; 1.57%, detection limit below 3 mg/L for all compounds. Proficiency test results in 2020 were satisfactory with Z-scores of all substances below 2. The method has been applied to analyze 200 distilled alcohol samples and 50 blended alcohol samples taken in Hai Duong city during the period from 2018 to 2020. Three of 200 distilled alcohol samples have the methanol content higher than the maximum limit. The relationship between methanol content in proportion to content of acetaldehyde, ethyl acetate, isobutyl alcohol, and isoamyl alcohol in the same sample has been evaluated to distinguish between blended alcohol and distilled alcohol.

Near-infrared spectroscopy to determine cold-flow improver concentrations in diesel fuel

The properties of diesel fuels must be controlled during industrial production. Significant diesel additives are cold-flow improvers that affect fuel properties at low temperature properties of diesel fuels. Improvers are added to fuels during processing in order to lower their cold filter plugging point (CFPP). In order to meet the European standard (EN 590), large quantities of cold-flow improvers may be required, increasing the cost of processing.In this study, near-infrared (NIR) spectroscopy was used for the rapid determination of cold-flow improver concentration. Our predictive models included 150 calibration standards and predictions were verified using 15 validation standards. The concentration of cold-flow improvers ranged from 41 to 325 mg/kg in the partial least squares (PLS) and from 60 to 325 mg/kg in the principal component regression (PCR) algorithm. The RSD of repeatability was 5.89% for the PLS algorithm and the RSD of 3.51% for the PCR algorithm of the model. Thus, NIR spectroscopy provides a fast and accurate tool for the determination of cold-flow improver concentrations in diesel fuel.

Study on the chemical constituents of nut oil from Prunus mira Koehne and the mechanism of promoting hair growth

Ethnopharmacological relevancePrunus mira Koehne (P. mira, Tibetan name: ཁམབུ།) is a kind of medicinal plant commonly used in Tibetan areas. The classic Tibetan medicine book Jingzhu Materia Medica records that “the nut oil from P. mira is used to cure loss of hair, eyebrows, beards, etc.” but the clinical experience has not been explored. Hair loss (alopecia) is a skin disease that becomes a common concern in Chinese society since it affects the appearance of a person. This paper studies the effectiveness of nut oil from P. mira in promoting hair growth and its working mechanism. Materials and methodsThe content of different components in the nut oil from P. mira was determined by HPLC. Two hair removal methods (sodium sulfide and hair removal cream) were used to study the effect of different doses on hair growth in KM mice. Then select the effective group, and use C57BL/6 mice to determine the number of hair follicles, dermal thickness, β-catenin, GSK3β and Wnt10 b mRNA and protein expression. ResultsThe contents of α-tocopherol, β-sitosterol, Vitamin E, Oleic acid and linoleic acid in nut oil from P. mira growing in 12 different regions were determined by HPLC. The linearity reached 0.999. The RSD of precision, stability, repeatability, and sample recovery was less than 3%. The dose-effect relationship suggested that 30.13 and 14.07 mg medicinal material·(cm2·d)−1 oil promoted hair growth and the dose effect was positively correlated. 30.13 mg medicinal material·(cm2·d)−1 nut oil from P. mira can accelerate hair follicles into the anagen, increasing Wnt 10 b mRNA expression, β-catenin mRNA and protein expression, and GSK-3 β protein expression. ConclusionThis study improved the quality control of nut oil from P. mira and found that it has the effect of promoting hair growth in mice. The working mechanism may be related to Wnt/β-catenin signaling pathway.