Novel Injectable Hydrogel Formulations and Gas Chromatography Analysis of the Residual Crosslinker in Formulations Intended for Pharmaceutical and Cosmetic Applications.

Novel hyaluronic acid (HA) crosslinked with pentaerythritol tetra-acrylate (PT) injectable hydrogels was invented. These injectable hydrogel/dermal filler formulations were synthesised using HA and the acrylate PT as a crosslinker under basic pH conditions using thermal crosslinking methods (oven heating), which provides a simple, safe, and eco-friendly method for crosslinking in 4 h under 45 °C. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses were conducted to represent the difference between the formulations in terms of peak formation and pore size, respectively. The crosslinking was partial as is considered to be typical for dermal injectable fillers. The rheological properties of these formulations showed that these novel dermal injectables are highly promising, and the newly developed fillers could be used with better results for dermal anti-wrinkle corrections, shaping, and volumising reasons. Furthermore, crosslinker (PT) residual analysis was carried out to state the formulations that are valid and acceptable for intradermal usage. The results from the GC method validation revealed it was a suitable method for this study. The GC analysis of all five injectable hydrogel/filler formulations demonstrated the formulations HA-PT 1, 2, 3 and 4 were formulated using (0.05-0.1)% w/w PT containing residual PT monomers within the safe limits that were determined to be below (0.008% w/w). This work has shown the development of a novel injectable hydrogel/filler formulation for pharmaceutical and cosmetic applications can be prepared in a more sustainable and simple way using pentaerythritol tetra-acrylate as a crosslinker agent, which holds great promise for the industry's future advancement.

Development and validation of a GC method for a key nemtabrutinib intermediate: Implementation of an in-situ free base sample preparation protocol.

A novel synthetic approach to nemtabrutinib (MK-1026) was recently developed in our laboratories. The chemistry goes through a cyrene amine intermediate which does not contain any chromophore. As a result, analysis of this key chiral intermediate by HPLC-UV is not feasible. Initial attempts to develop a HPLC-CAD method were unfruitful; therefore, a gas chromatography method was developed and optimized to effectively monitor the cyrene amine free base and related impurities generated during the process. As the synthetic process continued to be optimized, the toluene sulfonic acid salt (p-TsOH) of the cyrene amine intermediate was later identified by our process chemistry group to be beneficial in terms of ease of isolation and purity upgrade. However, repeated injections of the cyrene amine p-TsOH intermediate resulted in rapid GC column deterioration. After identifying p-TsOH as the main cause of the issue, we developed a straightforward and practical procedure that involves using a resin to remove the p-TsOH counterion in-situ, which converts cyrene amine salt to its neutral form in sample solutions. This protocol was successfully demonstrated and proven to be an efficient solution. This methodology may find applications with other analytes containing counterions that need to be neutralized prior to analysis.

Effect of relative humidity on the desorption of odour-active volatile organic compounds from paper and board: sensory evaluation and migration to Tenax®.

Paper and board are used for packaging of moist as well as dry food. According to Regulation (EC) No. 1935/2004, food contact materials (FCM) must not bring about a deterioration in the organoleptic characteristics of foodstuffs. For testing the transfer of off-flavour (taint) from packaging to food via the gas phase (DIN EN 1230-2), relative humidity (rH) has to be adjusted. In contrast, rH is neither taken into account when testing the odour (DIN EN 1230-1), nor in chemical migration of volatile organic substances (VOC) onto the adsorbent Tenax® (DIN EN 14338). In this work, effect of different rHs on the desorption of VOC from paper and board was investigated by GC-MS analysis as well as by human sensory tests. Raising humidity led to an increase in VOC transfer, which was observed by increasing peak areas as well as the detection of more substances in GC-MS. Analytical results were in line with human sensory tests. The odour profile of the paper at 33 and 58% rH was described as cardboard-like, sweet and smoky. Impact substances for these olfactory impressions were (E)-2-nonenal, vanillin and 2-methoxyphenol as identified by GC with an olfactory detection port (GC-ODP). The increase to 75 and 100% rH resulted in the additional perception of cheesy/sweaty and fatty/rancid impressions, which were primarily caused by short-chain fatty acids and di-unsaturated aldehydes.

The optimal combination of Nile red identification, colony polymerase chain reaction, and gas chromatography detection methods in screening for polyhydroxyalkanoicate-producing bacteria.

The study devised a detection process combining Nile red-containing media, polymerase chain reaction (PCR), and gas chromatography (GC) to evaluate the possibility of microbes becoming polyhydroxyalkanoate (PHA) producers. The Nile red and PCR detection steps of designating PHA producers had true positive rates of 39.4% and 40%, respectively, and the use of GC analysis as the final step yielded accurate results for the production types and yields of PHAs. When the number of screening samples was up to 102, connecting all three inspection methods in tandem generated economic benefits. When up to 105 samples were screened, the use of all three detection methods reduced the cost to 3% of the cost and the time consumed 6% of using just Nile red plus GC or PCR plus GC. However, when the sum of samples exceeded 108, the cost of combining the three methods exceeds 1 million US dollars and was excessive; here, the combination of Nile red plus PCR could be considered, even though the true positive rate was only 30.7%.

Thymus vulgaris L. essential oils from Emilia Romagna Apennines (Italy): phytochemical composition and antimicrobial activity on food-borne pathogens.

Between Modena and Bologna Apennines (Italy), several agricultural farms have recently been dedicated to the cultivation of autochthonous aromatic plants as primary cultivation or to complement other crops. In this study, the chemical composition of Thymus vulgaris L. essential oils (EOs) from this region was evaluated by means of gas-chromatographic analysis. Three different mulching techniques, in particular, soil coverage with grass, mulch with plastic film and with straw were investigated. The results highlighted that mulching techniques influenced the composition of the analysed EOs. All the EOs exerted good antimicrobial activity against clinical and food strains of the pathogen Listeria monocytogenes, with differences related to the composition. The EO obtained from plants covered with grass showed the best results, having MIC ≤ 2.5 µL/mL, and being able to inhibit also antibiotic-resistant strains, thus confirming that soil coverage with grass influences the composition and also the biological activity of Thymus vulgaris EO.

Improving the sensitivity of estimating CBD and other xenobiotics in plasma samples: Oleamide-induced transient matrix effect.

The paper discusses the matrix effect evoked by oleamide (OLA), a compound frequently found in samples processed and/or stored in lab polypropylene vials or disposable syringes. In the case of many substances a higher response for their samples containing OLA than for net solutions is observed. The analyte signal gain resulting from OLA presence in the examined sample depends on the ratio of OLA concentration to analyte concentration. A characteristic feature of the matrix effect evoked by oleamide is its short duration, which makes the chromatographic data (retention value and signal magnitude of examined compound) repeatable and reproducible. The identified "transient matrix effect" may significantly increase the sensitivity of many analytical procedures employing GC. Evoking the transient matrix effect by means of OLA in the experimental analytical quantitation of cannabidiol in plasma allowed to lower its limit of detection (LOD) by more than 50 %.

Gas Chromatographic and Spectrophotometric Determination of Diclofenac Sodium, Ibuprofen, and Mefenamic Acid in Urine and Blood Samples.

OBJECTIVES: Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of acute to chronic pain. A simple, fast, and reliable gas chromatographic (GC) method with flame ionization detection has been developed for the determination of NSAIDs such as diclofenac sodium, ibuprofen, and mefenamic acid after derivatization with ethyl chloroformate. MATERIALS AND METHODS: The GC conditions were optimized as elution from a DB-1 column (30 mx0.32 mm id) at column temperature 150 °C for 3 min, followed by a heating rate of 20 °C/min up to 280 °C and a hold time of 5 min. The nitrogen flow rate was 2.5 mL/min. For spectrophotometric studies, the absorbance was measured against methanol at a wavelength of 200-500 nm. RESULTS: The calibration curves were linear within 2-10 µg/mL with limits of detection of 0.4-0.6 µg/mL of each drug. The derivatization elution, separation, and quantitation were repeatable (n=3) with relative standard deviation (RSD) within 3.9%. The method was applied for the analysis of the drugs from pharmaceutical formulations and the results of the analysis agreed with labeled values with RSDs within 0.5-3.9%. The results were also confirmed by standard addition method. The percent recovery was calculated with spiked deproteinized human blood serum and urine samples and % recovery of the drugs was obtained within 96-98% with RSDs within 3.1%. CONCLUSION: The validated method proved its ability for the assay of NSAIDs in bulk and dosage form in a short analysis time. The method was also useful for the analysis of biological samples.

A method for the highly accurate quantification of gas streams by on-line chromatography.

Quantification of the gas streams from chemical systems such as catalytic reactors are routinely performed by on-line gas chromatography. Gas chromatographs used for this purpose are typically provided with a combination of thermal conductivity (TCD) and flame ionization (FID) detectors to be able to detect and quantify both permanent gases; COx, N2, H2, etc., and hydrocarbons. However, the accuracy of the quantification is hindered by the intrinsic limitations of each type of detector. Namely, TCD has low sensitivity and FID does not detect permanent gases. Therefore, modern gas chromatographs include methanizer units to partially overcome this shortcoming by converting COx to methane. However, as far as these authors know, the literature has not presented an analytical method to characterize gas streams with high accuracy by the simultaneous use of a combination of a TCD-FID detection system provided with a methanizer. This work is an attempt to solve this problematic; it consists of the formulation of a mathematical model for the well-known external and internal standard quantification methods in gas chromatography. The analysis of the gas stream from a catalytic reactor performing the combustion of methane was used to validate the developed method. The concentration ranges of the analysed gases were: 0.8-7.7 vol% of CH4, CO2, and CO, 7.7-38.5 vol.% of O2, and 46.2-90.8 vol.% of N2 at a total flow of 130 mL min-1. It was found that the commonly applied external standard method leads not only to inaccurate quantification but also to physically meaningless carbon balances and conclusions on the behaviour of the selected model system. In contrast, the internal standard method led to a highly accurate quantification with a physically meaningful carbon balance. Considering these findings, this contribution also draws attention to the need for a thoughtful application of chromatographic methods when studying the reactivity of gas systems.

New triacetic acid lactone glycosides from the fruits of Forsythia suspensa and their nitric oxide production inhibitory activity.

Three new triacetic acid lactone (TAL) glycosides, forsyphensides A-C (1-3) were isolated from the fruits of Forsythia suspensa. Their structures were elucidated by comprehensive spectroscopic techniques. The absolute configurations of their monosaccharides were determined by GC analysis. Notably, forsyphensides A-C were relatively rare TAL glycosides identified from plants. Compound 1 exhibited inhibitory activity against the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in microglia BV2 cells with the inhibition rate of 69.40%.

Essential oil composition and in vitro antibacterial activity of Chenopodium album subsp. striatum.

The objective of this study was to identify the bioactive compounds of essential oil and evaluate the antibacterial activity of the essential oil extracted from Chenopodium album subsp. striatum against multidrug-resistant bacterial strains (MDR) which were isolated from clinical specimens by conventional methods. Furthermore, eight different Gram-negative and Gram-positive multidrug-resistant bacterial strains were used to investigate the antibacterial potential of the essential oil. The antibacterial activity was tested using MIC and MBC microdilution method, well and disc diffusion in different concentration. The hydro-distillation of aerial parts powder yield was 0.466% (v/w). Essential oil showed bactericidal activity against both MDR Gram-negative and Gram-positive bacterial strains. MIC and MBC results were ranged from 0.31 to 2.5 and 0.62 to 5.0 mg/mL. The inhibition zones in well-diffusion method were ranged from 7 ± 0.6 mm to 15 ± 1.0 mm. Disc diffusion method was ranged from 7 ± 0.0 mm to 16 ± 0.6 mm depending on the type of bacteria strain and essential oil concentration. Essential oil of Ch. album had the greatest potential to be considered as an antibacterial agent against MDR bacteria strain. This potential was due to different biological and bioactive compounds like phytol, linalool, α-terpineol and linolenic acid in the plant.

Phenolic Compounds from Belamcanda chinensis Seeds.

Two new sucrose derivatives, namely, belamcanosides A (1) and B (2), together with five other known compounds (3-7), were isolated from the seeds of Belamcanda chinensis (L.) DC. Their structures were identified based on spectroscopic data. Especially, the absolute configurations of fructose and glucose residues in 1 and 2 were assigned by acid hydrolysis, followed by derivatization and gas chromatography (GC) analysis. Among the known compounds, (-)-hopeaphenol (3), (+)-syringaresinol (4), and quercetin (5), were isolated from B. chinensis for the first time. In addition, biological evaluation of 1 and 2 against cholesterol synthesis and metabolism at the gene level was carried out. The results showed that compounds 1 and 2 could regulate the expression of cholesterol synthesis and metabolism-associated genes, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), squalene epoxidase (SQLE), low density lipoprotein receptor (LDLR), and sortilin (SORT1) genes in HepG2 cells.

Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach.

Accurate determination of fatty acid contents is routinely required in microalgal and yeast biofuel studies. A method of rapid in situ fatty acid methyl ester (FAME) derivatization directly from wet fresh microalgal and yeast biomass was developed in this study. This method does not require prior solvent extraction or dehydration. FAMEs were prepared with a sequential alkaline hydrolysis (15 min at 85 °C) and acidic esterification (15 min at 85 °C) process. The resulting FAMEs were extracted into n-hexane and analyzed using gas chromatography. The effects of each processing parameter (temperature, reaction time, and water content) upon the lipids quantification in the alkaline hydrolysis step were evaluated with a full factorial design. This method could tolerate water content up to 20% (v/v) in total reaction volume, which equaled up to 1.2 mL of water in biomass slurry (with 0.05-25 mg of fatty acid). There were no significant differences in FAME quantification (p>0.05) between the standard AOAC 991.39 method and the proposed wet in situ FAME preparation method. This fatty acid quantification method is applicable to fresh wet biomass of a wide range of microalgae and yeast species.

Analysis of the essential oil components from different Carum copticum L. samples from Iran.

BACKGROUND: The family Apiaceae is defined with the diversity of essential oil. Fruits of Ajwain (Carum copticum), a famous herb of Apiaceae, accumulate up to 5% essential oil which is remarked as important natural product for food and flavoring industry, as well as pharmacological approaches. It is believed that differences in essential oil profile in a certain plant are resulted from various cultivation situations and locations, time of cultivation and also different extracting method. OBJECTIVE: Present study aimed to evaluate major components of ten different collected Ajwain samples from random cultivation locations of Iran. MATERIALS AND METHODS: Samples were individually subjected to hydrodistillation using a Clevenger-type apparatus for the extraction of essential oil. GC/MS analysis for samples was carried out using Agilent technologies model 7890A gas chromatograph with a mass detector. RESULTS: The yield of extracted essential oil was calculated as 2.2 to 4.8% (v/w) for ten samples. Major oil components were thymol, para-cymene and gamma-terpinene. Five of ten samples have thymol as the main component with amount of 35.04 to 63.31%. On the other hand, for four samples, para-cymene was major with amount of 40.20 to 57.31% and one sample had gamma-terpinene as main constituent containing 37.43% of total oil. Accordingly, three different chemotypes, thymol, para-cymene and gamma-terpinene can be speculated from collected samples. CONCLUSION: While these components possess pharmacological effect, screening of different chemotypes not only represent the effect of cultivation situations and locations but also can be beneficial in further investigation.

Waxy fraction containing long-chain aliphatic aldehydes in virgin olive oils.

Long-chain aliphatic aldehydes are natural minor components occurring in the cuticle of numerous plant species and also evidenced in virgin olive oils. The fraction containing these compounds can be isolated from the oil samples by using a solid-phase extraction silica-gel cartridge and then directly analysed by GC on a 5% diphenyl-95% dimethylsiloxane capillary column, using an on column-injection system. The proposed methodology showed that extra virgin olive oils contain long-chain aliphatic aldehydes, with even carbon-atom numbers from C22 to C30. Quantitative results, using the synthesised aldehyde C21 as internal standard, give concentrations of total long-chain aliphatic aldehydes in a variable range below 116mgkg-1, being hexacosanal (C26-al) the most abundant aldehyde. The different experimental conditions utilised during olive oil extraction processes influence the total aldehydes concentration. Besides contribution to the knowledge of the minor-component composition present in olive oil, their interest and relationship with wax esters, aliphatic alcohols and n-alkanes are discussed.

Smashing Tissue Extraction and GC Analysis of Active Fatty Acids from Oil Cake of Perilla Seeds / 中草药·英文版

Objective To optimize the extraction technology of perilla seeds oil from the oil cake of perilla seeds (OCPS) by using the contents of active fatty acids as evaluation standard. Methods The fatty acids were extracted from OCPS,the residue of perilla seeds after cold-press, by smashing tissue extraction (STE), the new technology selected through comparing with classical leaching extraction (LE), Soxhlet extraction (SE), ultrasonic extraction (UE), and supercritical-CO2 fluid extraction (SFE). For optimized condition of STE, orthogonal test was designed and completed. The contents of five fatty acids in extracted oil and OCPS were determined by GC. Results The optimized extraction parameters were smashing for 1.5 min under extraction power of 150 W and 1:6 of the material/solvent ratio. The contents of five fatty acids in the oils extracted by five techniques from OCPS and determined by GC were as follows:a-linolenic acid (41.12%-51.81%), linoleic acid (15.38%-16.43%), oleic acid (18.93%-27.28010), stearic acid (2.56%-4.01%), and palmitic acid (7.38%-10.77%). Conclusion The results show that STE is the most efficient technology with the highest yield (LE:0.57%; SE:1.03%; UE:0.61%; SFE:0.8(r; STE:1.17%) and shortest time (LE:720 min; SE:360 min; UE:30 min; SFE:120 min; STE:1.5 min) among five tested extraction technologies. It is fast reported using STE to extract herbal oil enriched with active fatty acids.