Individual Mono Research Articles

Individual mono and co-interactions of butylated hydroxytoluene and its metabolite with pepsin: Multi-pronged research strategies

In this study, the interactions between butylated hydroxytoluene (BHT) and its metabolite 2,6-Di-tert-butyl-p-benzoquinone (BHT-Q) with pepsin (PEP) were explored using multispectral measurements and computer prediction techniques. UV–vis absorption spectra, fluorescence lifetime, and Stern-Volmer quenching analysis showed static fluorescence quenching of PEP by BHT/BHT-Q. Negative thermodynamic parameters indicated that the spontaneous formation of complexes was primarily driven by van der Waals (vdW) forces and hydrogen bonds (HB). Synchronous fluorescence and circular dichroism spectroscopy revealed conformational changes induced by BHT/BHT-Q on PEP. Furthermore, BHT and BHT-Q inhibited PEP's enzymatic activity, while PEP suppressed their antioxidant activity. Interestingly, BHT-Q weakened BHT's binding strength to PEP, affecting the enzyme inhibition rate. Computer predictions highlighted the integral role of hydrophobic interactions. Moreover, BHT and BHT-Q exhibited different effects on the stability and compactness of PEP, the residue environment of PEP became more flexible or rigid in the presence of BHT and BHT-Q. Changes in the hydrophobic solvent accessible surface area (SASA) elucidated that the microenvironment of hydrophobic residues of PEP was changed after binding with BHT and BHT-Q. Ultimately, BHT's stronger binding affinity to PEP than BHT-Q was attributed mainly to its larger negative surface area, facilitating interactions with more amino acid residues.

The relationship between clinical impairment and blood drug concentration: Comparison between the most prevalent traffic relevant drug groups

AimThe aim of the present study was to investigate the relationship between blood concentrations of four different drug classes; ethanol, benzodiazepines, amphetamines and tetrahydrocannabinol (THC) and driver impairment as assessed by a clinical test of impairment (CTI). MethodsData was retrieved from a national database on CTI assessments and accompanying blood drug concentrations from apprehended drivers. All drug concentrations in blood were quantified using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS), and compared to the results of the CTI which were categorized as either “not impaired”, “mildly impaired”, “moderately impaired”, or “considerably impaired”. ResultsA total number of 15 514 individual mono drug-cases collected over 9 years was included. 89 % were men and the median age was 34 years. In addition, 3 684 individual cases with similar age and gender distribution where no drugs were detected, were included as a reference group. For ethanol and benzodiazepines the percentage of clinically impaired cases increased markedly from lower to higher concentration windows, from 60 % to 97 % for ethanol and from 38 % to 76 % for benzodiazepines. The corresponding increase for amphetamines and THC was modest, from 43 % to 58 % for amphetamines and from 41 % to 55 % for THC. The correlation between drug concentration and degree of impairment was high for ethanol (Spearman´s rho=0.548, p<0.001) and relatively high for benzodiazepines (Spearman´s rho=0.377, p<0.001), but low for amphetamines (Spearman´s rho=0.078, p<0.001) and THC (Spearman´s rho=0.100, p<0.001). ConclusionThe percentage of impaired drivers increased with increasing blood drug concentration for all four drug classes, most pronounced for ethanol and benzodiazepines and much less for amphetamines and THC. The median blood drug concentration increased with increasing magnitude of impairment for ethanol and benzodiazepines, while this was much less pronounced for amphetamines and THC. The ranges of drug concentrations, however, were wide for all four drug classes in all impairment categories as assessed by individual clinical examination.

Sugary solutions

Sugary solutions

Development of Measurement Procedures for the Characterization of Reference Materials for Carbohydrate Composition of Dairy Products

This article studies the development of measurement procedures based on various methods for a comprehensive analysis of the carbohydrate composition of food systems. The basis of the primary reference measurement procedure (PRMP) is the method of iodometric titration based on the ability of iodine to oxidize aldosaccharides to the corresponding uronic acids in an alkaline medium. The accuracy of the PRMP was improved by optimizing the measurement parameters, including the method of high-performance liquid chromatography with refractometric detection (HPLC/RD), and by establishing their possible variation limit based on a multifactorial experiment. The application of the PRMP made it possible to measure the mass fraction of carbohydrates (total sugar) as the sum of the mass fractions of reducing and non-reducing sugars in milk and dairy products, grain and milk products, low-lactose and lactose-free products, including those used for preparing baby food. In order to further detail the carbohydrate composition, highly selective methods were developed for measuring the mass fractions of lactose and galactose by the spectrophotometric (enzymatic) method, and the mass fractions of mono- and disaccharides by the HPLC/RD method in milk and dairy products. It was found that the measurement results of both the total content of carbohydrates and individual mono- and disaccharides in the samples of milk and dairy products obtained by various methods (iodometric titration, HPLC/RD, enzymatic method, refractometry, IR spectroscopy, calculation method) are consistent with each other subject to the stated uncertainties. Thus, the applicability of the developed PRMP in combination with other methods for conducting an in-depth analysis of the carbohydrate composition of milk and dairy products was confirmed. The developed procedures were used to characterize reference materials for the composition of dairy products (3 types), mono- and disaccharides (9 types).

​Effect of Inter and Sequential Cropping of Pulses in Little Millet (Panicum sumatranse L.) based Cropping System

Background: Small millets and pulses are world’s renowned crops for their nutritional significance. Being an underutilized species; rainfed farmers solely depend on them for their livelihood; which would be enhanced in a planned and efficient cropping system. The current study aimed to the identify suitable inter and sequential crops for rainfed little millet. Methods: In this study, four cropping patterns with two different row proportions for intercropping [viz., (4:1), (6:1)] were used with little millet as a main crop. The cropping systems include - little millet + pigeonpea [(4:1), (6:1)] followed by a sequential horsegram; little millet + pigeonpea followed by moth bean and little millet + lablab [(4:1), (6:1)] followed by Horsegram and little millet + lablab followed by mothbean. Result: Among them; a higher grain equivalent yield was observed in little millet + pigeonpea (6:1); followed by horsegram. However, higher dry matter, grain weight and higher individual crop yield was obtained in little millet + pigeonpea (6:1) followed by mothbean. Although individual mono cropping yields of these crops were higher; the pattern with little millet - pigeonpea (6:1) followed by horsegram could be recommended as a methodology to aid higher economic returns in shorter period.

Light Intensity and Temperature Effect on Salvia yangii (B. T. Drew) Metabolic Profile in vitro.

Plant in vitro culture is a feasible system for the testing influence of an environmental factor on the accumulation and chemodiversity of specialized metabolites, especially in medicinal plants. Light and temperature are among the most important factors affecting the physiology of plant organisms but their influence on specific metabolic pathways is not completely understood. Here, we examined the morphogenetic response, photosynthetic pigments content, lipid peroxidation level, DPPH radical scavenging activity, and the production of volatile and non-volatile constituents in Salvia yangii B. T. Drew (syn. Perovskia atriplicifolia Benth.) in vitro cultures kept under different light intensities (70, 130, and 220 μmol m−2 s−1) and at two selected temperatures (25 and 30°C). The experiment was continued for 7 months to monitor the changes in the treatment response in time. Phytochemical analysis was performed using chromatographic (GC-MS and UHLPC) and spectrophotometric techniques. The light intensity significantly influenced metabolic response in a non-linear manner, whereas temperature-induced adaptive modifications varied within the long cultivation. Significant differences were noted in the content of carnosic and rosmarinic acid, as well as in several sesquiterpenes (alloaromadendrene, β-caryophyllene, α-humulene). At elevated (30°C) temperature, a trend of differently modulated content of two major antioxidants—rosmarinic acid (RA, a phenylpropanoid pathway derived phenolic acid) and carnosic acid (CA, an abietane diterpenoid) was observed, where RA, but not CA, was depending on the light intensity. At 25°C, both compounds depended on light but in various ways. Among the volatile terpenoid compounds, the influence of light was pronounced, leading to modulation of proportions between individual mono- and sesquiterpenes as well as between hydrocarbon and oxygenated compounds. The study provided new information on the metabolic profile plasticity in S. yangii and added to the existing knowledge on the chemical adaptations in plant species from severe habitats.

EVALUATION OF ANTIOXIDANT POTENTIAL AND REDUCING POWER OF CALLUS INDUCED FROM LEAVES OF ASYSTASIA GANGETICA (L.) T.ANDERSON

Objective: Neuropathic pain arises from demage, or pathological changes in the peripheral or central nervous system. The pain is difficult to treat as standard treatment with conventional analgesics doesn`t typically provide effective relief of pain.&#x0D; Methods: It was a one year study of utilization and analysis of prescriptions for PNDs (Painful neuropathic disorders). The parameters evaluated were demographic profile of the patient (age and gender), type and etiology of PNDs, drug data (name of the group of drugs with individual drugs, mono or polytherapy, number of drugs per prescription, formulation) and associated adverse drug reactions (ADR) with the prescribed drug.&#x0D; Results: Maximum number of patients of PNDs resides in the age group of 18 – 35 y (41.2%) &amp; more common in females. The most common PND encountered was painful diabetic neuropathy (43.9%) followed by cervical and lumbar radiculopathy, postherpetic neuralgia. 2942 drugs were prescribed in 1020 prescriptions, out of which 96.8% were oral and 3.2% were topical formulations. Most frequently prescribed group of the drug was tricyclic antidepressants (27.3%) followed by anticonvulsants (25.3%). Polypharmacy was seen 89.7% as compared to monotherapy (10.3%). Only 132 ADRs of various types were seen. The most common organ system affected was central nervous system followed by gastrointestinal systems. The most common drugs implicated for ADRs were TCAs (24.4%), anticonvulsants (16.6%), and Pregabeline (9.8%). There were no fatal adverse events. Mild to moderate ADRs included constipation, nausea, vomiting, drowsiness, dryness of mouth.&#x0D; Conclusion: The choice of drug depends on etiology of neuropathic pain, drug efficacy and availability and also on ADR profile.

PATTERNS OF PRESCRIPTION AND ADR MONITORING OF DRUGS IN THE MANAGEMENT OF NEUROPATHIC PAIN IN A TERTIARY CARE TEACHING HOSPITAL

Objective: Neuropathic pain arises from damage or pathological changes in the peripheral or central nervous system. The pain is difficult to treat as standard treatment with conventional analgesics doesn`t typically provide effective relief of pain.&#x0D; Methods: It was a one-year study of utilization and analysis of prescriptions for PNDs (Painful neuropathic disorders). The parameters evaluated were demographic profile of the patient (age and gender), type and etiology of PNDs, drug data (name of the group of drugs with individual drugs, mono or polytherapy, number of drugs per prescription, formulation) and associated adverse drug reactions (ADR) with the prescribed drug.&#x0D; Results: Maximum number of patients of PNDs resides in the age group of 18 – 35 yrs (41.2%) &amp; more common in females. The most common PND encountered was painful diabetic neuropathy (43.9%) followed by cervical and lumbar radiculopathy, postherpetic neuralgia. 2942 drugs were prescribed in 1020 prescriptions out of which 96.8% were oral and 3.2% were topical formulations. Most frequently prescribed group of the drug was tricyclic antidepressants (27.3%) followed by anticonvulsants (25.3%). Polypharmacy was seen 89.7% as compared to monotherapy (10.3%). Only 132 ADRs of various types were seen. The most common organ system affected was the central nervous system followed by gastro intestinal systems. The most common drugs implicated for ADRs were TCAs (24.4%), anticonvulsants (16.6%), and Pregabeline (9.8%). There were no fatal adverse events. Mild to moderate ADRs included constipation, nausea, vomiting, drowsiness, dryness of mouth.&#x0D; Conclusions: The choice of drug depends on etiology of neuropathic pain, drug efficacy and availability and also on ADR profile.

Effects of replacement genetically modified soybean meal by a mixture of: Linseed cake, sunflower cake, guar meal and linseed oil in laying hens diet. Production results and eggs quality

The Kulmilk® (KulM®) preparation containing linseed cake (300 g/kg), sunflower cake (350 g/kg), guar meal (300 g/kg) and linseed oil (50 g/kg) was studied as alternative to genetically modified soybean meal (GM SBM) in the diet of laying hens. Two hundred forty hens maintained in cages were divided into 5 groups (8 hens per cage × 6 replications). From 18 wk of life, the hens were fed five diets for 33 wks: Control without KulM®, and A, B, C, D with respective KulM® content: 109, 170, 222 and 292 g/kg replacing GM SBM. Laying performance, egg weight, conversion ratio and hen mortality was continuously controlled throughout the experiment. Hen body weight was determined on 0 and 32 wk of production. On 7, 15 and 23 wk of laying, analysis of fresh eggs and eggs were stored for 21 d was performed (20 eggs per group). On 7 and 23 wk of hen laying, cholesterol level and fatty acid profile was determined on fresh eggs and eggs stored for 21 d (6 eggs per group). Sensory assessment of eggs was performed on eggs 15 wks laying. Introduction of KulM® to the diet replacing GM SBM contributed to increas laying performance, reduced mean egg weight and the final hen body weight but it did not influence the weight of eggs per hen, conversion ratio and mortality. The best production results were obtained in group A. Positive impact of KulM® was observed on the albumen quality and the yolk index of fresh and stored eggs, as well as reduction of yolk adhesiveness after 21 d. Cholesterol level in yolks depended on the laying performance, thus KulM® had indirect influenced on its reduction, especially in group A. Linear relationship was demonstrated between KulM® level and reduction of SFA acids, particularly of C16:0 acid. KulM® contributed to increas share of C18:1, C18:3 and C22:6 acids and reduction of C20:1 and C18:2 acids in the yolk. The influence of KulM® on the content of individual mono- and polyunsaturated fatty acids was observed primarily in group D. No impact of KulM® on the sensory quality of eggs could be demonstrated. In summary, KulM® can be recommended as a safe and efficient substitute of GM SBM in laying hens diet, particularly at a concentration of the diet at 109 g/kg.

Metabolome adjustments in ectomycorrhizal Populus × canescens associated with strong promotion of plant growth by Paxillus involutus despite a very low root colonization rate.

It is believed that resource exchange, which is responsible for intensified growth of ectomycorrhizal plants, occurs in the fungus-plant interface. However, increasing evidence indicates that such intensified plant growth, especially root growth promotion, may be independent of root colonization. Nevertheless, the molecular adjustments in low-colonized plants remain poorly understood. Here, we analysed the metabolome of Populus × canescens microcuttings characterized by significantly increased growth triggered by inoculation with Paxillus involutus, which successfully colonized only 2.1±0.3% of root tips. High-throughput metabolomic analyses of leaves, stems and roots of Populus × canescens microcuttings supplemented with leaf proteome data were performed to determine ectomycorrhiza-triggered changes in N-, P- and C-compounds. The molecular adjustments were relatively low in low-colonized (M) plants. Nevertheless, the levels of foliar phenolic compounds were significantly increased in M plants. Increases of total soluble carbohydrates, starch as well as P concentrations were also observed in M leaves along with the increased abundance of the majority of glycerophosphocholines detected in M roots. However, compared with the leaves of the non-inoculated controls, M leaves presented lower concentrations of both N and most photosynthesis-related proteins and all individual mono- and disaccharides. In M stems, only a few compounds with different abundances were detected, including a decrease in carbohydrates, which was also detected in M roots. Thus, these results suggest that the growth improvement of low-colonized poplar trees is independent of an increased photosynthesis rate, massively increased resource (C:N) exchange and delivery of most nutrients to leaves. The mechanism responsible for poplar growth promotion remains unknown but may be related to increased P uptake, subtle leaf pigment changes, the abundance of certain photosynthetic proteins, slight increases in stem and root amino acid levels and the increase in flavonoids (increasing the antioxidant capacity in poplar), all of which improve the fitness of low-colonized poplars.

Characterisation, release and migration of phenolic compounds from resoles used in polyester-phenol coatings intended for food contact materials

ABSTRACT Resoles are multifarious pre-polymeric resins produced by the condensation of basic chemicals phenols, formaldehyde and optionally aliphatic alcohols like butanol. They are widely used as cross-linkers to form resistant internal coatings on metal surfaces of cans, containers or closures. Although the application of resoles is common in food contact, usually little is known about their exact composition, the toxicological hazards of their individual constituents and the migration of phenolic compounds, e.g., of the potentially endocrine-disrupting chemical bisphenol F. Our study fills major gaps of knowledge in risk assessment, using the example of a two-layer polyester-phenol coating system, which is based on three different resoles and is commercially used for closures of infant food glass jars. Various analytical approaches, namely size-exclusion chromatography, nuclear magnetic resonance spectroscopy, liquid chromatography coupled to mass spectrometry, fluorescence and diode array detection as well as gas chromatography-mass spectrometry were evaluated to quantitatively characterise resoles. Additionally, derivatisation with dansyl chloride as well as Folin–Ciocalteu colorimetric assay was adapted first times to determine the total phenol content from technical resoles. Individual mono- and bisphenols were determined in resoles up to about 120 mg/g, while the concentration of bisphenol F isomers was below 10 mg/g. Migration from the coating system was determined after sterilisation (121°C, 1 h, 20% ethanol). Results were ~2 µg/dm2 for identified individual mono-phenols like 2-hydroxybenzyl alcohol and up to ~120 µg/dm2 for total phenolic compounds, representing approximately 7% of the overall migration. The migration of bisphenol F isomers was negligible below 0.3 µg/dm2. Potential exposure to migrating phenols was assessed based on the threshold of toxicological concern concept to be significantly below for individual phenols and in the same order of magnitude for total phenols compared to the respective thresholds calculated for infants.

Length- and Thickness-Dependent Optical Response of Liquid-Exfoliated Transition Metal Dichalcogenides

Because of their reduced dimensionality, two-dimensional materials show intriguing optical properties and strong light-matter interaction. In particular, group VI transition metal dichalcogenides have been extensively studied and proof-of-principle optical applications have been demonstrated. Most studies to date focus on individual mono- or bilayered micromechanically exfoliated samples, which often display significant variations between flakes. In this work, we study size-dependent optical properties of four group VI TMD materials: WS2, MoS2, WSe2, and MoSe2, each consisting of ensembles of nanosheets suspended in the liquid environment. Samples were produced by liquid-phase exfoliation and size-selected using cascade centrifugation with size and layer number distributions quantified by statistical atomic force microscopy. Differences in lateral size and layer number are reflected in systematic changes in the optical extinction and absorbance spectra, which we exploit to establish quantitative spectroscopic metrics to facilitate the measurement of nanosheet dimensions for each of the four materials. The lowest energy resonance, referred to as A-exciton, is analyzed in more detail. In all cases, an exponential red shift with increasing layer number is observed. Our experimental data, backed up with first-principle calculations, reveal that the magnitude of the shift is dependent on the molecular mass of the central metal atom (W, Mo), while the rate at which the peak shifts from monolayer to bulk depends on the band gap of the semiconductor.

Mono- and multi-nucleated ventricular cardiomyocytes constitute a transcriptionally homogenous cell population

Individual adult ventricular cardiomyocytes are either mono- or multi-nucleated and undergo morphological changes during cardiac hypertrophy. However, corresponding transcriptional signatures, reflecting potentially different functions or the ability for cell-cycle entry, are not known. The aim of this study was to determine the transcriptional profile of mono- and multi-nucleated adult cardiomyocytes by single-cell RNA-sequencing (scRNA-seq) and to investigate heterogeneity among cardiomyocytes under baseline conditions and in pressure-induced cardiac hypertrophy. We developed an array-based approach for scRNA-seq of rod-shaped multi-nucleated cardiomyocytes from both healthy and hypertrophic hearts. Single-cell transcriptomes of mono- or multi-nucleated cardiomyocytes were highly similar, although a certain degree of variation was noted across both populations. Non-image-based quality control allowing inclusion of damaged cardiomyocytes generated artificial cell clusters demonstrating the need for strict exclusion criteria. In contrast, cardiomyocytes isolated from hypertrophic heart after transverse aortic constriction showed heterogeneous transcriptional signatures, characteristic for hypoxia-induced responses. Immunofluorescence analysis revealed an inverse correlation between HIF1α+ cells and CD31-stained vessels, suggesting that imbalanced vascular growth in the hypertrophied heart induces cellular heterogeneity. Our study demonstrates that individual mono- and multi-nucleated cardiomyocytes express nearly identical sets of genes. Homogeneity among cardiomyocytes was lost after induction of hypertrophy due to differential HIF1α-dependent responses most likely caused by none-homogenous vessel growth.

A standard, analytical protocol for the quantitation of non-structural carbohydrates in seagrasses that permits inter-laboratory comparison

Non-structural carbohydrate (NSC) content provides a quantitative measure of seagrass response to environmental stress and recovery. A review of the literature shows that numerous analytical methods are used to measure seagrass NSC. Colorimetric methods are most commonly used; however, these methodologies lack precision and provide no insights with respect to individual monosaccharides released by hydrolysis. We determined experimentally that assays by high performance liquid chromatograph (HPLC) are more precise and capable of estimating carbohydrates to within 1.1% of expected carbohydrate levels, compared to a greater than 15.0% deviation by colorimetric assays (phenol-sulfuric acid). Furthermore, solvents used for soluble sugar extraction (ethanol/water, methanol/water and water) and starch gelatinization (hydrochloric acid and sodium hydroxide) result in significantly different NSC estimations. Thus, estimation of seagrass NSC by different analytical protocols are non-comparable. We present an optimized 5-step protocol for the quantitation of seagrass soluble NSC and starch using HPLC that identifies individual mono- and oligosaccharides. Creating and using a standardised protocol for NSC quantitation will create a more cogent bio-indicator that enables comparisons of estimates between studies. Additionally, quantitation of individual sugars by HPLC will enable detailed investigation of seagrass metabolic responses to environmental stress.

Semiparallel deep neural network hybrid architecture: first application on depth from monocular camera

Deep neural networks have been applied to a wide range of problems in recent years. Convolutional neural network is applied to the problem of determining the depth from a single camera image (monocular depth). Eight different networks are designed to perform depth estimation, each of them suitable for a feature level. Networks with different pooling sizes determine different feature levels. After designing a set of networks, these models may be combined into a single network topology using graph optimization techniques. This “semiparallel deep neural network (SPDNN)” eliminates duplicated common network layers and can be further optimized by retraining to achieve an improved model compared to the individual topologies. Four SPDNN models are trained and have been evaluated at two stages on the KITTI dataset. The ground truth images in the first part of the experiment are provided by the benchmark, and for the second part, the ground truth images are the depth map results from applying a state-of-the-art stereo matching method. The results of this evaluation demonstrate that using postprocessing techniques to refine the target of the network increases the accuracy of depth estimation on individual mono images. The second evaluation shows that using segmentation data alongside the original data as the input can improve the depth estimation results to a point where performance is comparable with stereo depth estimation. The computational time is also discussed in this study.

Hydrogen evolution activity of individual mono-, bi-, and few-layer MoS2 towards photocatalysis

We investigate the hydrogen evolution activity in the dark and under illumination above the band gap of individual mono-, bi- and few-layer (bulk) MoS2 flakes. We demonstrate that the electrocatalytic activity of 2H-MoS2 immersed in 1M H2SO4 increases with decreasing number of layers. For monolayers, we observe the highest exchange current density, which is one magnitude larger than in the bulk case. The onset potential scales with the number of layers, which is consistent with a previous report, suggesting that hopping transport across inter-layer barriers within the MoS2 flakes is responsible for this scaling. A specially designed micro-sized catalytic cell enables us to investigate individual MoS2 flakes with well-known geometry and edge-to-surface ratio. Taking these geometric parameters into account, we tentatively attribute the catalytic activity mainly to sulfur vacancies in the basal planes acting as active sites. The associated turn over frequencies (TOF) for mono- and bi-layer MoS2 yield values higher than 103s−1 at an overpotential of −0.2V vs. RHE. In view of light driven hydrogen evolution as a means of solar energy conversion, we investigate the photocatalytic activity of few-layer MoS2 under white light illumination.

Impact of mono- and poly-ester fractions on polysorbate quantitation using mixed-mode HPLC-CAD/ELSD and the fluorescence micelle assay

Determination of excipient content in drug formulation is an important aspect of pharmaceutical formulation development and for analytical testing of the formulation. In this study, the influence of polysorbate subspecies, in particular mono- and poly-esters, for determining polysorbate (PS) content were investigated by comparing three of the most widely used PS quantitation approaches, the Fluorescence Micelle Assay (FMA) and Mixed-Mode High Performance Liquid Chromatography coupled with Charged Aerosol Detection (MM-CAD) or Evaporative Light Scattering Detection (MM-ELSD). FMA and MM-CAD were employed to investigate the quantitation behavior of PS20 and PS80 subspecies and corresponding degradation products in placebo formulations using forced degradation conditions at 40°C for up to 12 weeks. While both methods allowed accurate and comparable quantification of neat PS at the beginning of stress studies, pronounced differences in content determination between the methods were observed at later time points, which were attributable to substantial differences in the contribution of individual mono- and poly-esters to the overall quantitation results. It was particularly surprising to find that the main component of PS20, polyoxyethylene sorbitan monolaurate, did not show a signal at the studied concentration using FMA. Moreover, the degradation of polysorbate poly-esters, was reflected much stronger in FMA than MM-CAD results. Additional experiments employing chemical oxidation and base hydrolysis to degrade PS20, quantified by FMA and MM-ELSD, also show preferential reduction in certain subspecies depending on the degradation pathway involved. For PS20 degraded by chemical oxidation, quantitation results were lower for FMA than MM-ELSD, while the opposite trend was observed with base hydrolysis.

Comparative Thermal Characteristics and Fatty Acid Composition of Mono- and Diacylglycerols of Lard and Some Commercial Emulsifiers

A study was carried out to compare the fatty acid composition and thermal profiles of mono- and diacylglycerols of six commercial emulsifiers, coded as E1, E2, E3, E4, E5, and E6, purchased from different manufacturers with those of the same derived from lard. The lipid extraction from the commercial emulsifiers was done using the Soxhlet method and the isolation of individual mono- and diacylglycerols was carried out using a column chromatographic method. The isolated partial acylglycerols of lard and individual emulsifiers were subjected to fatty acid analysis by gas chromatography and thermal analysis by differential scanning calorimetry. A clear distinction between lard-based emulsifier and the commercial emulsifiers was achieved by the application of principal components analysis to the fatty acid data. According to thermal analysis, mono- and diacylglycerols of lard displayed significant differences from those of commercial mono- and diacylglycerols with respect to the thermal transitions in the cooling curves. This study concluded that partial acylglycerols of none of the commercial emulsifiers employed in this study displayed similarity to those of lard-based emulsifiers.

Improved gas chromatography-flame ionization detector analytical method for the analysis of epoxy fatty acids

In this study an improved method for analysis of epoxy fatty acids is reported. Data obtained from analysis of polar fatty acids has previously been presented, but due to the high number of compounds that co-elute in the polar fraction, the resultant chromatograms are complex which may lead to compromising the accuracy of the data. A three steps separation of fatty acid methyl esters (FAMEs) by solid-phase extraction (SPE) on a silica gel column to remove hydroxy fatty acid interferences was proposed. This approach is opposed to a two step separation procedure that has been often used to prevent analytical interferences caused by non-altered fatty acids. A gas chromatograph with a flame ionization detector (GC-FID) equipped with a polar CP-Sil 88™ column was used. Quantification was based on the use of methyl nonadecanoate (C19:0), as an internal standard. Individual mono epoxy fatty acids were well separated without co-eluting compounds. The optimized method was finally applied to screen epoxy fatty acids in 37 fresh oil samples. Results obtained for the total epoxy fatty acids were in the range 0.03–2mgg−1 of oil with repeatability coefficient of variation (CV) ranging from 2.8 to 9.9% for duplicate analysis showing that the results obtained are repeatable.

A Comparative Evaluation of Mono-, Di- and Triglyceride of Medium Chain Fatty Acids by Lipid/Surfactant/Water Phase Diagram, Solubility Determination and Dispersion Testing for Application in Pharmaceutical Dosage Form Development

PurposeTo compare physiochemical properties of mono-, di- and triglycerides of medium chain fatty acids for development of oral pharmaceutical dosage forms of poorly water-soluble drugs using phase diagrams, drug solubility, and drug dispersion experiments.MethodsPhase diagrams were prepared using a monoglyceride (glycerol monocaprylocaprate: Capmul MCM® EP), a diglyceride (glycerol dicaprylate) and two triglycerides (glycerol tricaprylate: Captex 8000®; caprylic/capric triglycerides: Captex 355 EP/NF®) in combination with a common surfactant (PEG-35 castor oil: Cremophor EL®) and water. Psuedoternary phase diagrams using mixtures of monoglyceride with either diglyceride or triglyceride were constructed to determine any potential advantage of using lipid mixtures.ResultThe monoglyceride gave microemulsion (clear or translucent liquid) and emulsion phases, whereas di- and triglycerides exhibited an additional gel phase. Among individual mono-, di- and triglycerides, the oil-in-water microemulsion region was the largest for the diglyceride. Gel phase region within diglyceride and triglyceride phase diagrams could be practically eliminated and microemulsion regions expanded by mixing monoglyceride with di- or tri-glycerides (1:1). Addition of a model drug, danazol, had no effect on particle sizes of microemulsions formed. Dispersion of drug in aqueous media from mixtures of mono- and diglyceride or mono- and triglyceride was superior to individual lipids.ConclusionSystematic study on comparison of mono-, di- and triglyceride of medium chain fatty acids will help formulators select components for optimal lipid-based formulation.