Elution Method Research Articles

Fabrication of multiscale structure by hybrid process with short-pulsed laser and electrochemical machining

Electrochemical machining (ECM) is a well-established elution method with high processing speed, application to hard-to-cut material and less tool wear as noncontact between a workpiece and a tool. However, ECM is hard to process precisely and fabricate nanostructures. A short-pulsed laser (SPL), on the other hand, can fabricate fine periodic structures called as LIPSS (laser-induced periodic surface structures), which has been reported to provide materials with functionalities such as the reduction of friction, the change of wettability and the improvement of biocompatibility. Nevertheless, an SPL capable of fabricating nanostructures is unstable for the creation of large scale shapes. The appropriate processing method depends on the scale of the demanded shape and structure, and it takes long processing time with the complicated process to create the shape and fabricate nanostructures on the surface. The hybrid manufacturing process with an SPL and ECM (SPLECM) was then proposed to fabricate multiscale structures effectively, that an SPL increasing electric filed intensity enables ECM to improve the processing speed and fabrication of nanostructures on the electrochemical machined surface. In this study, the effects of the hybrid process with an SPL and ECM on the fabrication of multiscale structures on 304 stainless steel substrates were investigated experimentally. The proposed method capable of improving processing speed and fabricating multi-scale structures were stated. This study demonstrated the efficacy of SPLECM to create a shape and fabricate nanostructures on the surface simultaneously.

Presence of pyrroloquinazoline alkaloid in Adhatoda vasica attenuates inflammatory response through the downregulation of pro-inflammatory mediators in LPS stimulated RAW 264.7 macrophages.

Introduction: Inflammation is the primary response caused due to harmful stimuli which are followed by the increased draining of plasma and immune cells from the body into the site of the injured tissue. A signaling cascade of growth factors and cytokines propagates and eventually matures in the inflammatory site involving the blood vessels and immune markers within the injured tissue in order to promote the renewal of the degenerated tissue. During a chronic disorder like diabetic foot ulcer, there is an obstinate inflammation which may act as a prime factor for limb amputation and upon persistent prevalence may even lead to death. Methods: This study focuses on the mode of action of ALK-F (alkaloid fraction) isolated from Adhatoda vasica in attenuating the nitric oxide production which was estimated by Griess assay, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) expression was analyzed by ELISA and expression of COX-2 and iNOS by RT-PCR and western blotting in LPS stimulated RAW 264.7 macrophages. Total intracellular ROS was analyzed by DCFH-DA probing and the presence of quinazoline alkaloid (vasicine) in the ALK-F was evidenced by high performance liquid chromatography (HPLC). Results: The ALK-F of A. vasica exhibited a significant inhibitory effect on LPS elicited nitrite production (13.2 ± 1.06 µM), iNOS, and COX-2 (2.6 and 3.3 fold) in a dose-dependent manner. There was a significant decrease in the generation of these pro-inflammatory cytokines TNF-α (1102 ± 1.02 pg/mL) and IL-6 (18 ± 0.87 ng/mL) and total intracellular ROS in the highest tested concentrations (1 µg and 10 µg) of ALK-F of A. vasica. HPLC analysis by the gradient elution method revealed the presence of 12% of quinazoline alkaloid vasicine in the crude alkaloid fraction. Conclusion: Thus this study communally suggests that attenuation of nitric oxide and the dysregulation of genes responsible for inflammation which deliberates A. vasica to conflict against inflammation and provide remedial benefits in diabetic wound care.

Understanding the sorption behaviour of Pu/U on zirconium phosphosilicate prepared by gelation route

Abstract Zirconium phosphosilicate (ZPS) has been prepared by gelation route for its ion exchange applications. ZPS was characterised by X-ray diffraction technique (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), Fourier transformed Infrared Spectrometry (FTIR) and surface area analysis. K+ ion exchange behaviour was studied by pH titration. The material was found to extract Pu selectively over U from different mineral acids. Pu sorption behaviour on ZPS packed column was also been carried out. The pore volume was evaluated as 0.1336 mL g−1. The FTIR revealed the presence of –OH and PO4 3− groups on the surface of the material, while the SEM image indicates the irregular morphology and size of the sorbent. Different isotherm model: Langmuir, Freundlich, Dubinin–Rodushkevich and Temkin were used to understand the nature of sorption, while Lagergren 1st order, Intraparticle diffusion and pseudo 2nd order kinetics were used for modelling sorption kinetics. Suitable elution method was used for quantitative stripping of plutonium from sorbent. The radiolytic stability of the sorbent was evaluated upto 1500 kGy. A comparative evaluation of the sorption process has also been carried out with that reported in literature.

Elution methods to evaluate colistin susceptibility of Gram-negative rods

Recently it was developed the Colistin Broth Disk Elution test which uses colistin disks as a source of these antibiotics. The aim of this study was to evaluate the performance of protocols that used diminished volumes of the reagents: the Colistin Broth Microelution (CBM) (1 mL) and the Microelution-Plates Test (MPT) (200 μL), as well as the Colistin Susceptibility Test Tube (CSTT), which uses only one colistin disk added to a tube containing broth. The tests were performed with 85 Gram-negative isolates collected from surveillance studies. The CBM, MPT, and CSTT tests presented a good Categorical Agreement (CA), Essential Agreement (EA), sensitivity and specificity to Enterobacterales isolates, however the ME and VME were less satisfactory. The results for non-fermentative isolates were not satisfactory. In conclusion, the proposed methods, mainly the CSTT, can be used as screening tests to detect colistin resistant among Enterobacterales, as they are an easy and inexpensive option to the reference method.

Development of an extraction method to detect enteric viruses in dressed vegetables

Food-borne viral infections are caused mainly by noroviruses (NoV) and the hepatitis A virus (HAV), which respectively cause gastroenteritis and hepatitis.Various foods have been implicated in viral outbreaks, including vegetables that are consumed in a variety of forms, often with salad dressing. NF EN ISO procedures (15216-1:2017) propose standard methods for quantifying NoV and HAV in high-risk food categories, such as vegetables, based on viral elution and PEG concentration methods, but these methods are not suitable for composite meals like salads dressed with oily, fatty or emulsified food ingredients. The development of sensitive and reliable techniques for the detection of viruses in these products is therefore needed to ensure the safety of these products. The aim of this study was to develop an RT-qPCR based method for the detection and quantification of NoV and HAV in various vegetables with different dressings. Three methods for recovering NoV and HAV from artificially contaminated dressed vegetables were evaluated. The selected method was based on the use of Trizol reagent and, according to the type of dressing, the limit of detection ranged from 104 to 106 genome copies/g for NoV and from 102 to 103 PFU/g for HAV. The described method can be applied for detecting NoV and HAV in food containing salad dressing for routine diagnosis needs.

Identification and Validation of Synthetic Phenolic Antioxidants in Various Foods Commonly Consumed in Malaysia by HPLC

This study was conducted in order to identify the presence of four synthetic phenolic antioxidants (SPAs): propyl gallate (PG), tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in various food stuffs that are commonly consumed in Malaysia. The identification method was optimized and validated before it was applied to the analyses of eighty three food samples which include chewing gum, chili sauce, cereal-based snack food, noodles, potato snack, cereal breakfast, oat, biscuit, cookie, coffee, junk food, seaweed, nut, chocolate, apple juice, orange juice and blackcurrant juice. Twenty nine food samples contained SPAs either singly or in combination. The chromatography conditions such as elution method, flow rate and wavelength were optimized. Good linearity ranges (1–300 mgL–1) were found for all the four phenolic antioxidants. RSD for repeatability and reproducibility ranged from 0.15–0.84% for both precision analyses. LOD and LOQ ranged from 0.02–0.67 and 0.06–2.03 mgL–1, respectively. Recoveries of the four SPAs ranged from 80.4 to 119.0% when selected food items spiked at 10, 50, and 100 mgL–1.

Pharmacokinetic comparison of five xanthones in rat plasma after oral administration of crude and processed Garcinia hanburyi extracts

Gamboge, a dried resin secreted by Garcinia hanburyi Hook. f. (Guttiferae), possesses remarkable anticancer activity. However, due to toxicity, it must be processed before use in clinics. Xanthones are the main bioactive ingredients in gamboge. In order to elucidate the influence of processing technology on pharmacological properties of gamboge, an efficient, sensitive, and selective ultra-performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-MS/MS) method of five critical xanthones, including β-morellic acid (β-MA), isogambogenic acid (IGNA), gambogenic acid (GNA), R-gambogic acid (GA), and S-GA in rat plasma was established for a comparative pharmacokinetics study of these xanthones after oral administration of crude and processed G. hanburyi extracts. The chromatographic separation of these five xanthones along with an internal standard (I.S.) was carried out on a Waters Acquity UPLC BEH C8 column with a gradient elution method using acetonitrile/0.1% formic acid-water as mobile phases. The eluate was detected by multiple-reaction monitoring (MRM) scanning with an electrospray ionization source operating in the positive ionization mode. Sample preparation involved a liquid-liquid extraction of the five analytes with ethyl acetate. Deoxyschizandrin was employed as an internal standard. This assay method was validated for selectivity, linearity, intra-day and inter-day precision, accuracy, recovery, matrix effect, and stability. The results revealed that the calibration curves displayed good linear regression (r > 0.995), and the lower limit of quantification (LLOQ) was <5.52 ng/mL for each analyte. The intra-day and inter-day precision (RSD) of the five xanthones at low, medium, and high levels was <10.58%, and the bias of the accuracy ranged from −8.54 to 10.2%. All other parameters fulfilled the FDA criteria for bioanalytical validation. In addition, the assay was successfully applied to the determination and pharmacokinetic study of these five xanthones after oral administration of crude and processed gamboge. Furthermore, Cmax of GNA and AUC0−t of IGNA were increased significantly (P < 0.05) after processing, while AUC0−t of β-MA, R-GA, and S-GA decreased remarkably (P < 0.05), which suggested that processing exerted different effects on the absorption of xanthones. The results might be valuable for the clinical reasonable application and understanding the processing mechanism of gamboge.

Evaluation of the materials properties, stability and cell response of a range of PEGDMA hydrogels for tissue engineering applications

The main aim of this study was to examine the stability of a range of polyethyleneglycol dimethacrylate (PEGDMA) hydrogels over a 28-day period in simulated physiological solution. Upon optimisation of the ultraviolet (UV) curing conditions, the PEGDMA hydrogels were prepared using four different monomer concentrations (25, 50, 75 and 100 wt% PEGDMA) in water and cross-linked by photopolymerisation. Initial results revealed a correlation between monomer concentration and swelling behaviour, where a decrease in swelling was observed with increase in monomer content. On storage in physiological solutions at 37 °C, a decrease in the weight remaining of the hydrogels and the pH of the solutions was observed over a 28-day period. Using scanning electron microscopy, the surface topography of the hydrogels appeared to get smoother and in parallel changes in hydrophilicty were observed, with the biggest changes observed for the higher monomer concentrations where water contact angle values were seen to increase toward 90°. However, the mechanical properties remained relatively unaffected and there was no adverse effect on cell metabolic activity observed for cells grown in the presence of PEGDMA samples or using elution methods. Looking at the combination of mechanical chemical and thermal properties shown these results are an important finding for scaffolds intended for tissue engineering applications, where provision of mechanical support without the elicitation of an inflammatory response due to polymer degradation products is crucial for successful integration and neotissue formation during the first 28 days post implantation.

Simultaneous determination of three carbamate pesticides using vortex-assisted liquid–liquid microextraction combined with HPLC-amperometric detection

In this study, a vortex-assisted liquid–liquid microextraction procedure for simultaneous determination of three carbamate pesticides (desmedipham, phenmedipham and chlorpropham) was developed and for a first time was combined with high-performance liquid chromatography with amperometric detection (HPLC-AD) on a glassy carbon electrode. Variables that affect the procedure were studied, and optimal conditions were found to be 125 μL of toluene as the extraction solvent, 60 s of vortexing at 3000 rpm and a 3 mL sample volume. The HPLC-AD measurements were carried out using the gradient elution method, with a mobile phase consisting of methanol, a buffer solution at pH 3 and detection potential of +1.3 V. The developed method was successfully applied for the analysis of two types of samples: aqueous (wine, beer, apple juice) and solid (potato).

Recovery and Detection of Enteric Viruses from Non-Traditional Irrigation Water Sources.

The variability of environmental water samples impacts the allowance of one method to be universally ideal for all water types and volumes. Surface and reclaimed waters can be used for crop irrigation and may be referred to as non-traditional irrigation waters as these water types may be associated with a higher risk of microbial contamination compared to groundwater. These waters are typically more microbially and chemically complex than groundwater and have a higher risk of viral contamination. To detect viruses in these water types, an infinite number of variations can be made to traditional recovery methods. This protocol was developed based on a commonly used virus adsorption and elution (VIRADEL) method. Additional steps were included to simplify and efficiently reduce particulates in the viral concentrate and remove DNA from eluted nucleic acids prior to detection. Method alterations allow for volumes up to 40 liters to be processed with consistent recovery of enteric viruses including Aichi virus, hepatitis A virus, and noroviruses belonging to genogroups GI and GII. No inhibition was observed among either surface or reclaimed water samples. This protocol could be utilized in the monitoring of a wide array of irrigation water sources throughout irrigation processes.

Quality Evaluation of Andrographis paniculata Capsules Based on Rapid and Accurate LC-ESI-MS/MS Assay of Three Diterpenoids.

Andrographis paniculata is an important traditional Chinese herbal material widely used for treatment of fever and diarrhea. The three diterpenoids [andrographolide (AP), dehydroandrographolide (DP) and neoandrographolide (NP)] in A. paniculata were characterized as the key active components for its extractive and related medicinal preparations. A rapid and accurate quantitative analysis of these three diterpenoids in A. paniculata capsules was accomplished by means of a valid and reliable high-performance liquid chromatography with tandem mass spectrometric (HPLC-MS/MS) analytical method. An optimized gradient elution method, which under the mobile phase consisting of methanol and water, was established successfully. An XDB C18 column (3.5μm, 2.1mm×50mm) was successfully applied to separate these three diterpenoids at the flow rate of 0.55mL/min. A triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) mode using an electrospray ionization source was served for analytical detection. The linearity, specificity, accuracy, recovery, precision, stability and repeatability were demonstrated to fully confirm the validity of this study. Good linear regression relationships for the three analytes were obtained over the range of 0.50-1000ng/mL. Intra-day and inter-day precisions were evaluated with relative standard deviation<7.62%, and the extraction recovery varied from 93.8% to 102.0%. The rapid and accurate HPLC-MS/MS analytical method was developed for the quality evaluation of A. paniculata capsules successfully. The content of AP, DP and NP obtained were 3.90-4.08, 4.77-5.04, 4.32-4.48mg/g in A. paniculata capsules, respectively. Moreover, it is expected that this analytical technique can be applied to detect three effective components rapidly and accurately in other different medicinal preparations of A. paniculata as a method for their quality control.

Methanol linear gradient counter-current chromatography for the separation of natural products: Sinopodophyllum hexandrum as samples

Counter-current chromatography (CCC) is a unique, liquid-liquid partition chromatography process. Both the mobile and stationary phases are liquids, so no solid support matrix is used. CCC has gained wide acceptance as a preparative technique in a variety of fields. Because the mobile and stationary phases are both liquids, gradient elution is difficult to perform with CCC. Phase equilibrium must be maintained, so any change in the composition of one phase may induce a compositional change in the other. In this work, a new linear gradient elution method was developed for CCC. Biphasic solvent systems containing heptane, ethyl acetate, methanol, and water (HepEMWat) in various ratios were prepared and used to optimize both isocratic and linear gradient CCC separation with methanol. We first separated a test mixture of four standard compounds with partition coefficients ranging from 0.8 to 7.8. The separation resembled a reversed-phase process, and elution was performed while progressively decreasing the polarity of the mobile phase. Target molecules with small partition coefficients eluted first in the lower phase of the optimized HepEMWat solvent system. Elution of constituents with large partition coefficients was quite slow under isocratic conditions. Separation time was significantly reduced when elution was performed with a linear gradient using methanol and the optimal HepEMWat system. Elution with a 3:7:4:6 (v/v/v/v) HepEMWat system took approximately 200 min. This included an 80-min isocratic step, followed by gradient elution with methanol from 0% to 30%. The optimized methanol linear gradient CCC method was then used to separate a complex mixture of natural products isolated from Sinopodophyllum hexandrum (Royle) Ying roots. Twelve compounds with a wide range of polarities were well-resolved in a single separation. We have developed a convenient and cost-effective strategy for the separation of complex mixtures. No tedious mobile phase preparation step is required. The volume of unused mobile phase is minimal, so little solvent is wasted. The method is an important advance for the separation of mixtures that contain many compounds with a large range of polarities and partition coefficients, which are common features of natural products.

Simultaneous determination of cardiovascular drugs in dried blood spot by liquid chromatography-tandem mass spectrometry

A dried blood spot (DBS) sampling method was exploited to extract cardiovascular drugs using a small volume of whole blood of human and rodent. Thereafter, an analytical method using liquid chromatography with tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of 12 cardiovascular drugs. A 6 mm internal diameter disc containing 10 μL of blood was punched from a specifically designed card and analyzed by LC-MS/MS using a gradient elution method with a total run time of 16 min. For sample separation, a universal octadecyl-silica column was used with a flow rate of 0.2 mL/min. The developed method was validated in terms of linearity, accuracy, and precision, which showed satisfactory results. In addition, the matrix effects were closely investigated to confirm the extraction efficiency. Additionally, the stability was tested by storing DBSs at room temperature; the results showed that these drugs were stable for at least 30 days. Accordingly, the proposed LC-MS/MS method is capable to analyze several cardiovascular drugs in a single analysis. It can be applied to therapeutic drug monitoring in patients as well as in the in vivo settings.

Measurements of Ion Binding to Lipid-Hosted Ionophores by Affinity Chromatography.

The binding affinity between antibiotic ionophores and alkali ions within supported lipid bilayers was evaluated using affinity chromatography. We used zonal elution and frontal analysis methods in nanovolume liquid chromatography to characterize the binding selectivity of the carrier and channel ionophores valinomycin and gramicidin A within different phosphatidylcholine bilayers. Distinct binding sensitivity to the lipid phase, both in affinity and selectivity, is observed for valinomycin, whereas gramicidin is less sensitive to changes in a membrane environment, behavior that is consistent with ion binding occurring within the interior of an established channel. There is good agreement between the chromatographic retention and the reported binding selectivity measured by other techniques. Surface potential near the binding site affects ion retention and the apparent association binding constants, but not the binding selectivity or enthalpy measurements. A model accounting for the surface potential contributions of retained ions during frontal analyses yields values close to intrinsic binding constants for gramicidin A (KA for K+ between 70 and 120 M-1) using reasonable estimates of the initial potential that is postulated to arise from the underlying silica.

Identification, isolation and characterization of dolutegravir forced degradation products and their cytotoxicity potential

Dolutegravir was approved by USFDA, Canada and European regulatory authorities as antiretroviral medication. In this article, DLG forced degradation studies as per the International Council for Harmonization (ICH) prescribed stress conditions was conducted and the resulting degradants were fully characterized. DLG was stable in basic, thermal and photolytic stress conditions, whereas DLG was found to unstable in acidic and oxidative conditions. One degradant each from acid and peroxide treated solutions was resolved on LC–MS and labelled as DP-1 and DP-2 with RT 1.80 min and 1.41 min, respectively. DP-1 and DP-2 were isolated by preparative HPLC with C18 column using gradient elution method. Subsequently DP-1 and DP-2 peaks were subjected to HRMS for accurate mass. Molecular mass of DP-1 and DP-2 were m/z 420.1379 (positive mode) and m/z 214.0319 (negative mode), respectively. Further, DP-1 & DP-2 were subjected to NMR spectroscopic analysis (including 2D) for structural confirmation. DP-1 was identified as N-(2,4-difluorobenzyl)-9-hydroxy-2-(4-hydroxybutan-2-yl)-1,8-dioxo-2,8-dihydro-1H-pyrido[1,2-a]pyrazine-7-carboxamide and it is earlier reported by Gudisela et al. [19] as DLG process impurity. DP-2 was identified as 2-(2,4difluorobenzylamino)-2-oxoacetic acid which is novel DLG degradant and not reported earlier to the best of our knowledge. DLG along its forced degradation products were found to be non-cytotoxic in in vitro assay conditions using HepG2 cells.

Separation of five diketopiperazines from the marine fungus Alternaria alternate HK-25 by high-speed counter-current chromatography.

High-speed counter-current chromatography was applied to the separation of five diketoperazines from the marine Alternaria alternate HK-25 for the first time using one-step elution method with a pair of two-phase solvent systems composed of petroleum ether/ethyl acetate/methanol/water (5.5:11:5:7, v/v). Where 151.6mg of crude sample yielded five diketoperazines, 12,13-dihydroxy-fumitremorgin C (1), gliotoxin (2), demethoxyfum itremorgin C (3), bisdethiobis(methylthio)gliotoxin (4), fumitremorgin C (5), and the purities of all compounds were above 94% as determined by high-performance liquid chromatography. The structures of these compounds were identified by 1 H and 13 C NMR spectroscopy. These results showed that high-speed counter-current chromatography can provide a feasible way for highly effective preparation of marine natural products, which ensured the supple of numerous samples for drug development.

Determination of N-acetylcysteine in the presence of ciprofloxacin or levofloxacinin microparticulate dry powder inhalers

A fast and easy method was validated for simultaneous determination of ciprofloxacin hydrochloride monohydrate (CP), levofloxacin hemihydrate (LV), and N-acetylcysteine (NAC) in samples. The analysis was performed on a C$_{18}$ column (250 x 4.6 mm, 5 μm) (Inertsil ODS-3V) using an isocratic elution method with a mobile phase composed of 25 mM KH$_{2}$PO$_{4}$ (pH 3.0) and methanol (72:28, v/v) at a flow rate of 1 mL/min. UV detection was performed at 214 nm for NAC and 293 nm for CP and LV. The method was validated for linearity, accuracy, precision (repeatability and reproducibility), specificity, sensitivity, and stability. The calibration study using several media demonstrated that the calibration curves were linear for all compounds in all media (R$^{2}$ > 0.9993). The limit of detection was 0.098 μg/mL for CP, 0.049 μg/mL for LV, and 0.487 μg/mL for NAC. The limit of quantification was 0.328 μg/mL for CP, 0.165 μg/mL for LV, and 1.624 μg/mL for NAC. Precision and accuracy values of the method fulfilled the required limits. All these outcomes demonstrate that the validated HPLC method is appropriate for simultaneous analysis of CP, LV, and NAC in samples for content uniformity of dry powder inhaler and permeability studies.

A novel molecularly imprinted electrochemical sensor based on double sensitization by MOF/CNTs and Prussian blue for detection of 17β-estradiol

In this paper, we constructed MIL-53 (AlOHbdc, bdc = benzene-1,4-dicarboxylate) /CNTs and Prussian blue (PB) as the double sensitization material of the sensing platform, in which the MIL-53/CNTs hybrid can not only increase the specific surface area but also increase the conductivity of the sensor and PB can play a role in amplifying electrical signals and accelerating electron transmission. Pyrrole was used as monomer and E2 was used as template for electropolymerization to form conductive film. Moreover, the overoxidation/dedoping elution method were used to simplify the experimental process. Under optimal conditions, the MIECS exhibited an excellent sensitivity and high selectivity with a wide linear response range between 10−14 to 10−9 mol L−1 and an estimated detection limit of 6.19 × 10−15 mol L−1.

Evaluation of methods for elution of HEV particles in naturally contaminated sausage, figatellu and pig liver

Foodborne transmission of HEV is a growing public health concern in industrialised countries, where the disease is mainly autochthonous, caused by zoonotic HEV of either genotype 3 or 4. Foodstuffs containing pig's liver were suspected on several occasions to be the cause of autochthonous cases of HEV infection, while the transmission was associated with animal contact and the ingestion of raw or uncooked meat, especially liver. In assessing the risk related to the presence of HEV in food, detection methods were previously developed but HEV detection rates seem to vary with the type of samples and methods. As foodstuff containing pig liver can be contaminated with HEV internally, an efficient virus extraction procedure is required. The aim of this study was to evaluate six methods for their efficiency in releasing HEV viral particles from figatelli, pig liver sausages and liver samples previously tested positive for the presence of HEV. The ratio weight to volume of elution buffer (1:5) and the FastPrep®-24 homogeniser showed to significantly improve the quantity of HEV genomes released per gram of figatelli and pig liver sausages. To our knowledge, this study is the first to evaluate several methods for elution of HEV particles from naturally contaminated pig liver products, and may be extended for quantifying other viral genomes from food of animal origin.

Predicting pharmacokinetic behaviour of drug release from drug-eluting embolization beads using in vitro elution methods

Drug-eluting Embolic Bead - Transarterial Chemoembolisation (DEB-TACE) is a minimally invasive embolising treatment for liver tumours that allows local release of chemotherapeutic drugs via ion exchange, following delivery into hepatic arterial vasculature. Thus far, no single in vitro model has been able to accurately predict the complete kinetics of drug release from DEB, due to heterogeneity of rate-controlling mechanisms throughout the process of DEB delivery. In this study, we describe two in vitro models capable of distinguishing between early phase and late phase drug release by mimicking in vivo features of each phase. First, a vascular flow system (VFS) was used to simulate the early phase by delivering DEB into a silicon vascular cast under high pulsatile flow. This yielded a burst release profile of drugs from DEB which related to the dose adjusted Cmax observed in pharmacokinetic plasma profiles from a preclinical swine model. Second, an open loop flow-through cell system was used to model late phase drug release by packing beads in a column with an ultra-low flow rate. DEB loaded with doxorubicin, irinotecan and vandetanib showed differential drug release rates due to their varying chemical properties and unique drug-bead interactions. Using more representative in vitro models to map discrete phases of DEB drug release will provide a better capability to predict the pharmacokinetics of developmental formulations, which has implications for treatment safety and efficacy.