Phosphate Buffer Research Articles

Ready-to-Use Flowable Hydraulic Tricalcium Silicate-Based Dental Cement Paste with Antibiotic Releasing Capacity

Calcium silicate-based cements have been investigated recently for various medical applications. One notable application is using calcium silicate cement in dental root canal treatments. This work aimed to develop a novel flowable dual-paste calcium silicate sealer with an extended capacity for releasing antibiotic drugs. This study prepared a composite dental cement incorporating tri- and dicalcium silicate (C2S and C3S) and nano-hydroxyapatite (nHA). International standards are followed by the sealers' film thickness, flowability values, working time, and setting time. The formation of calcium hydroxide and calcium silicate hydrate was proved in the XRD patterns, which attributed to the hydration of C2S and C3S. The in vitro release of Amoxicillin (AMX) loaded in the composite cement was conducted in deionized (DI) water and phosphate-buffered saline (PBS) and investigated using Higuchi and Weibull models. Upon immersion in PBS, the sedimentation of hydroxyapatite layer on the cement surface, led to a comparatively slower AMX release rate than that in water. The results of the agar diffusion test showed that the presence of the antibiotic drug improved antibacterial properties in such a way that by adding AMX in the cement formulation, the diameter of the inhibition zone increased from 31.61 mm in TCS to 40.17 mm in TCS- 30 mM sample after 72 hours. These results imply that the drug-loaded cement pastes hold potential for application as a bioactive dental root canal sealer, offering antibiotic-loading properties with long-term release capabilities.

Polymerizable Cholinium-Based Antibiotics for Polymer Carriers: Systems with Combined Load of Cloxacillin and Ampicillin

Single and dual-drug delivery systems (DDSs) based on linear choline polymers were designed through the controlled polymerization of a pharmaceutically functionalized monomer, i.e., [2-(methacryloyloxy)ethyl]trimethylammonium, with counterions of cloxacillin (TMAMA/CLX), or its copolymerization with [2-(methacryloyloxy)ethyl]trimethylammonium with ampicillin (TMAMA/AMP), providing antibiotic properties. This strategy was effective in attaining well-defined linear copolymers with 38–93 mol. % of TMAMA content, which were regulated by the initial ratio of TMAMA to methyl methacrylate comonomer. The polymer compositions were controlled by the total monomer conversion (40–75%), resulting in a variable degree of polymerization (DPn = 160–300) and pharmaceutical anion contents (CLX− 51–80% and AMP− 78–87%). In aqueous solution, the polymers formed particles with sizes ranging between 274 and 380 nm for CLX− systems and 288–348 nm for CLX−/AMP− systems. In vitro drug release, driven by the exchange of pharmaceutical anions with phosphate ions in phosphate-buffered saline (PBS), imitating a physiological fluid, demonstrated release efficiencies of 58–76% for CLX− (10.5–13.6 µg/mL) in single systems, and 91–100% for CLX− (12.9–15.1 µg/mL) and 97–100% for AMP− (21.1–23.3 µg/mL) in dual systems. Compared to conventional systems delivering antibiotics without a polymer carrier, the choline-based polymer DDS attained satisfactory levels of drug loading content and (co-)release from the polymer carriers, offering a promising alternative for antibiotic delivery.

Impedimetric Biosensors for the Quantification of Serum Biomarkers for Early Detection of Lung Cancer

Lung cancer is the most common type of cancer diagnosed worldwide and is also among the most fatal. Early detection, before symptoms become evident, is fundamental for patients’ survival. Therefore, several lung cancer biomarkers have been proposed to enable a prompt diagnosis, including neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA). NSE and CEA are two serum proteins whose elevated levels have been associated with lung cancer. Hence, in this study, impedimetric biosensors (immunosensors) able to quantify NSE and CEA were developed as proof-of-concept devices for lung cancer diagnosis. The sensing platform exploited for the immunosensors comprises a novel combination of a magnetic platform, screen-printed gold electrode (SPGE), and magnetic nanobeads (MB). The MB were functionalized with antibodies to capture the analyte from the sample and to move it over the sensing area. The immunosensors were then developed by immobilizing another set of antibodies for either CEA or NSE on the SPGE through formation of self-assembled monolayer (SAM). The second set of antibodies enabled a sandwich assay to be formed on the surface of the sensor, while MB manipulation was applied during the sensor performance to depict a microfluidic system and increase antigen–antibody complex formation prior to CEA or NSE detection and quantification. The optimized immunosensors were successfully tested to measure various concentrations of CEA and NSE (0–100 ng/mL) in both phosphate buffer and 100% human serum samples. Clinically relevant detection limits of 0.26 ng/mL and 0.18 ng/mL in buffer and 0.76 ng/mL and 0.52 ng/mL in 100% serum for CEA and NSE, respectively, were achieved via electrochemical impedance spectroscopy with the use of potassium ferri/ferrocyanide as a redox probe. Hence, the two immunosensors demonstrated great potential as tools to be implemented for the early detection of lung cancer.

Simultaneous Detection of Glucose and Acetoacetate in Artificial Urine Samples Using 3D-Connector Microfluidic Paper Based Analytical Devices

Diabetic patients sometimes experience both hyperglycemia and hyperketonemia simultaneously. This condition requires proper management of glucose and ketone body biomarkers. The fluctuating intensity of these biomarkers necessitates regular monitoring. This study aims to develop concept non-enzymatic measurement method by integrating µPADs (microfluidic paper-based analytical devices) for detecting glucose and acetoacetate in artificial urine samples. The method uses silver nanoparticle formation for glucose detection and Schiff base reaction as well as the Rothera test for acetoacetate detection. Optimal conditions found include the glucose detection zone with volume ratio of AgNO3 500 mM : starch 3% (w/v) (1 : 1), and the acetoacetate detection zone with glycine 900 mM in phosphate buffer pH 9.4. The artificial urine sample combination consists of glucose, acetoacetate, and acetone with volume ratio of (1 : 1 : 1). The 3D-Connector for glucose uses NaOH 10 M : starch 3% (w/v) with volume ratio of (1 : 3), while for acetoacetate, sodium nitroprusside 15% (w/w) in DMF 5% (v/v). Validity for glucose measurement shows linearity (R² = 0.9664), precision (RSD = 4.56%), accuracy (88.75 – 99.62%), LOD (1.61 mM), and LOQ (5.37 mM). Conversely, acetoacetate measurement shows linearity (R² = 0.9636), precision (RSD = 1.24%), accuracy (99.44 – 99.73%), LOD (1.41 mM), and LOQ (4.69 mM).

Modeling inactivation of non-proteolytic Clostridium botulinum type B spores in a plant-based fish alternative

Our study aims to assess the thermal inactivation of non-proteolytic type B Clostridium botulinum spores in a plant-based fish and to evaluate the potential of alternative heat treatments at temperatures below the safe harbor guidelines established for vacuum-packed chilled products of extended durability. First, the heat resistance of the spore suspension was determined using capillary tubes in potassium phosphate buffer at 80°C. The D80 value was estimated to be 0.7–0.8 min. Then, inactivation was studied in a plant-based fish alternative using “thermal cells equipment.” Inactivation kinetics were obtained at four temperatures: 78, 81, 84 and 85°C, in duplicates. A secondary model describing log10D values versus temperatures was fitted to the dataset. The model parameters ZT and log10Dref (log10D at Tref 82°C) were estimated to be 8.02 ± 0.46°C and 0.32 ± 0.02, respectively. Model validation was done first with additional data collected at three different temperatures (79.1, 82.5, 87.5°C) and second with literature data. The time required to deliver 6 log reduction in the plant-based food matrix was predicted at temperatures within the range 80–90°C. The recommended processing for vacuum-packed chilled products, 90°C for 10 min, was evaluated. We demonstrated that the recommended processing is approximately five times more than the time required for 6 log reduction of non-proteolytic C. botulinum in the plant-based fish alternative, indicating a substantial margin of safety. Our findings highlight the importance of conducting product-specific studies for the evaluation of thermal processing and the potential of process optimization for certain product categories.

Thiamethoxam-Loaded Ethyl Cellulose Microspheres for Extending the Efficacy Duration and Reducing the Toxicity on the Growth of Maize (Zea mays L.).

Thiamethoxam has been widely used in agriculture due to its excellent insecticidal activity. However, thiamethoxam is prone to loss during practical applications, especially in soil application, which seriously reduces its performance. In this work, thiamethoxam is loaded in ethyl cellulose microspheres to solve this issue, and the thiamethoxam-loaded ethyl cellulose microspheres (thiamethoxam/EC) are facilely and effectively fabricated by emulsified solvent volatilization. The exceptional embedding capacity of thiamethoxam/EC was elucidated through a systematic investigation of its controlled release and antiphotolysis properties. The encapsulation efficiency of thiamethoxam/EC was found to be ∼70.36%. Even after 130 h in a phosphate-buffered saline solution, the release of thiamethoxam from the thiamethoxam/EC complex continued, with a cumulative release of ∼52.38%. In contrast, the cumulative release of thiamethoxam/EC in soil after being flushed with 580 mL of water was a mere 14.74%, significantly lower than the value of 42.73% observed for unencapsulated thiamethoxam at the same volume. Additionally, thiamethoxam/EC demonstrated benign biocompatibility with Escherichia coli and maize (Zea mays L.) seedlings. The ultraviolet resistance of thiamethoxam in the thiamethoxam/EC formulation was nearly 3 times greater than that of uncoated thiamethoxam, and the insecticidal efficacy against Mythimna separata improved by 11.46% at a low concentration of 1 mg/L after a 10 day incubation in a greenhouse. The microspheroidization process not only extended the efficacy duration of fluazinam on target crops but also contributed to the sustainable use of pesticides and environmental protection.

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

The rising popularity of bioconjugate therapeutics has led to growing interest in late-stage functionalization (LSF) of peptide scaffolds. α,β-Unsaturated amino acids like dehydroalanine (Dha) derivatives have emerged as particularly useful structures, as the electron-deficient olefin moiety can engage in late-stage functionalization reactions, like a Giese-type reaction. Cheap and widely available building blocks like organohalides can be converted into alkyl radicals by means of photoinduced silane-mediated halogen-atom transfer (XAT) to offer a mild and straightforward methodology of alkylation. In this research, we present a metal-free strategy for the photochemical alkylation of dehydroalanine derivatives. Upon abstraction of a hydride from tris(trimethylsilyl)silane (TTMS) by an excited benzophenone derivative, the formed silane radical can undergo a XAT with an alkyl bromide to generate an alkyl radical. Consequently, the alkyl radical undergoes a Giese-type reaction with the Dha derivative, forming a new C(sp3)–C(sp3) bond. The reaction can be performed in a phosphate-buffered saline (PBS) solution and shows post-functionalization prospects through pathways involving classical peptide chemistry.

SMP30 Alleviates Oxidative Stress and Regulates Ca2+-ATPase Activity in UVR-B-Induced Cataracts in Rats

Purpose Oxidative stress, ultraviolet radiation, and calcium imbalance are key components in the onset and advancement of cataract, which continue to be the leading cause of blindness globally. An important newly discovered aging maker, Senescence marker protein 30 (SMP30) regulates calcium and participates in mitigating oxidative stress damage. Here, we examined the beneficial role of SMP30 in protecting against ultraviolet radiation type B (UVR-B)-induced cataract in rats. Methods Wistar rats (2 months) were arbitrarily assigned into 4 groups of 10 rats. These groups included the Control group, UVR-B group, adeno-associated virus 2 vectors negative control (AAV2-NC) group, and adeno-associated virus 2-mediated overexpression of SMP30 (AAV2-SMP30) group. The control group received Phosphate-buffered saline (PBS) via injection, while the AAV2-NC group and AAV-SMP30 group were separately injected with AAV2-NC and AAV2-SMP30 vectors. In addition to the control group, the remaining three experimental groups were subjected to ultraviolet light exposure 4 weeks post-injection. The lens opacity was examined by stereoscopic microscope, and the lenses were separated to measure oxidative damage parameters particularly superoxide dismutase (SOD), glutathione peroxidase (GPX), and Ca2+-ATPase activity. The localization and expression of SMP30 and Ca2+-ATPase in the lenses were determined using immunohistochemistry and RT-qPCR. Results After UVR-B irradiation, the AAV2-SMP30 group exhibited a substantial decrease in lens opacity compared to the UVR-B group. The results revealed a notable downregulation of SMP30 expression and the activities of SOD, GPX, and Ca2+-ATPase of rat lens following exposure to UVR-B radiation. However, SMP30 overexpression partially reversed these effects. In vivo experiments demonstrated SMP30 overexpression attenuated the UVR-B-induced decline in SOD, GPX, and Ca2+-ATPase activities. Conclusion This study demonstrates that SMP30 has the potential to reduce lens opacity caused by UVR-B by increasing antioxidant stress and regulating Ca2+-ATPase activity. SMP30 might be a cutting-edge target for the treatment of cataracts.

Pivotal Role of the Intracellular Microenvironment in the High Photodynamic Activity of Cationic Phthalocyanines.

To investigate the influence of phthalocyanine aggregation on their photodynamic activity, a series of six cationic water-soluble zinc(II) phthalocyanines bearing from four to sixteen 4-((diethylmethylammonium)methyl)phenoxy substituents was synthesized. Depending on their structure, the phthalocyanines have different aggregation behaviors in phosphate buffer solutions ranging from fully assembled to monomeric states. Remarkably, independent of aggregation in buffer, very high photodynamic efficiencies against the tumor cell lines MCF-7 and MDA-MB-231 in the nanomolar range were found for all investigated phthalocyanine, and the IC50(light) varied from 27 to 358 nM (3.5 J/cm2, 660 nm) with IC50(dark)/IC50(light) ratios up to ∼3700. This is due to the intracellular disassembly of aggregated phthalocyanines with the formation of monomeric photoactive forms, as demonstrated by fluorescence microscopy. Indeed, the interaction of aggregated phthalocyanines with serum proteins in a buffer resulted in the disassembly of nonluminescent aggregate species with the release of photoactive monomers bound to protein macromolecules.

A Hemicyanin-Based Water-Soluble off-on Fluorescence and Colorimetric Probe for Detecting HSO3-/SO32- in Real Samples.

A fluorescence and colorimetric sensor (AHT) was developed to detect HSO3-/SO32- in a 10 mM aqueous PBS buffer at pH 7.4. AHT exhibits non-fluorescence in the buffer due to the intramolecular charge transfer (ICT). The detection of HSO3⁻/SO32⁻ by probe AHT occurs through nucleophilic addition to its carbon-carbon double bond, which disrupts conjugation and stops the ICT process. This reaction induced a visible color change from violet to colorless and activated fluorescence from "off" to "on" at 485nm (λex = 420nm). The probe exhibited significant selectivity and sensitivity for HSO3⁻/SO32⁻, with a detection limit of 51.5 nM and a rapid response time. Additionally, it effectively detected HSO3⁻/SO3²⁻ in real samples, e.g., sugar, water, wine, and biscuits.

Transient Anti-TCRβ mAb Treatment Induces CD4+ T Cell Exhaustion and Prolongs Survival in a Mouse Model of Systemic Lupus Erythematosus.

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Chronic T cell receptor (TCR) signalling induces T cell exhaustion, characterised by reduced capacity to induce tissue damage. Here, we investigated the therapeutic potential of the anti-TCRβ (H57-597) monoclonal antibody (mAb) in a mouse model of SLE. Four-month-old MRL/lpr mice exhibiting SLE phenotypes received 5 weekly doses of anti-TCRβ mAb or phosphate-buffered saline (PBS) vehicle control. Subsequently, mouse survival was monitored daily. On day 1 post the final dose of treatment, SLE pathogenesis was determined using histological staining and spot urine test. T and B cell states in the brain, kidney, and secondary lymphoid organs were determined by flow cytometry. Transient treatment of anti-TCRβ mAb significantly prolonged the survival of MRL/lpr mice. Accordingly, MRL/lpr mice in the anti-TCRβ mAb group exhibited decreased proteinuria scores and minimal renal pathological damage compared to the PBS control group. Flow cytometric analysis revealed that anti-TCRβ mAb treatment resulted in a reduction in the frequencies of CD4+ T cells and CD138+B220lo/- plasma cells, plus an increase in Foxp3+ regulatory T cell frequency. Furthermore, CD4+ T cells from anti-TCRβ mAb treated mice exhibited elevated expression levels of PD-1 and TIM-3, with reduced IFN-γ production, indicative of an exhaustion-like phenotype. Therefore, transient administration of anti-TCRβ mAb treatment induces an exhaustion-like phenotype in CD4+ T cells, resulting in prolonged survival of MRL/lpr mice. Inducing autoreactive T-cell exhaustion holds promise as an attractive therapeutic approach for SLE.

Boosting Hydrogen Evolution Reaction on Co9S8 in Neutral Media Leveraging Oxophilic CrOx Mosaic Dopant

AbstractThe electrochemical production of sustainable hydrogen under neutral conditions is advantageous, as it allows for the use of wastewater or seawater without the need for pH adjustments. However, the low ion concentration in neutral electrolytes typically results in limited adsorption of reactants on the catalyst surfaces, leading to sluggish reaction kinetics. Therefore, enhancing absorption capacity is a key challenge in the development of neutral hydrogen evolution reaction (HER) catalysts. Hetero‐structured catalysts may improve surface adsorption through extensive interfacing between phases, enabling active transportation of reaction intermediates. Integrating metal sulfides and oxides, in particular, holds the potential for generating efficient electrocatalysts with improved HER activity and surface adsorption capacity. Herein, the synthesis of CrOx‐doped Co9S8/CuCrS2 mosaic hetero‐nanostructures is reported as a proficient HER catalyst. Facile Cr‐cation migration at the Co9S8/CuCrS2 interface enables the preparation of Cr‐oxide sub‐nano domains within the sulfide matrix, boosting the HER catalysis in neutral media. The exceptional electrochemical performance is demonstrated in a pH 7.4 phosphate buffer solution, including low overpotential, small Tafel slope, and stability over 60 h. The formulation of catalyst design and synthetic approaches has the potential to pave the way for diverse catalytic applications utilizing metal oxide‐doped hetero‐nanostructures.

DETAILED ELECTROCHEMICAL BEHAVIOR INVESTIGATION AND DETERMINATION OF ANTIPSYCHOTIC DRUG PALIPERIDONE ON A GLASSY CARBON ELECTRODE

Objective: A sensitive and cost-effective electrochemical method was developed on a bare glassy carbon electrode (GCE) for the determination of paliperidone (PAL), an antipsychotic drug used in the primary schizophrenia treatment affecting the whole world. Material and Method: The oxidation studies carried out in pH 8 phosphate buffer solution (PBS) by cyclic voltammetry (CV) showed that the oxidation reaction of PAL is a process including the same number of electrons and protons. The electrochemical detection of PAL was carried out by differential pulse voltammetry (DPV). Result and Discussion: The linearity range was between 1 µM and 100 µM. The limit of detection (LOD) and quantification (LOQ) values were calculated as 2.41x10-7 M and 8.033x10-7 M, respectively. The applicability of the developed method was confirmed by using it on synthetic human serum. The relative standard deviation (RSD) values were less than 2%. The selectivity of the analysis was demonstrated over against interfering substances such as ascorbic acid, KNO3, MgCl2, paracetamol, dopamine, Na2SO4, and uric acid with recovery% and RSD% values in the range 98.32%-101.56% and 0.15%-1.99%, respectively. The proposed method provided high sensitivity for PAL and is the first reported method for the electroanalysis of PAL.

Assessment of biofilm formation on ceramic, metal, and plastic brackets in orthodontic materials by new method using renG-expressing Streptococcus mutans.

Oral biofilm has a high acid-producing capacity, increases the risk of enamel demineralization around brackets, and has been identified as a problem in orthodontic treatment. Here, we assessed the risk of biofilm formation by Streptococcus mutans, which is associated with the development of white spot lesions (WSL) on tooth surfaces, using multibracket devices. Various types of brackets were used for the biofilm formation assay with S. mutans coated with human saliva, immersed in renG-expressing S. mutans UA159 (strain with the luciferase gene inserted), and incubated overnight at 37°C under aerobic conditions containing 5% CO2. The biofilm was washed twice with phosphate-buffered saline (PBS), and 200 μL of luciferin dissolved in PBS was added to each well. The mixture was light shielded and allowed to react for 20 min. Luminescence was measured as the amount of biofilm formed by live cells on the bracket surfaces using an optical emission spectrophotometer. Biofilm formation was greater in plastic brackets than in ceramic and metal brackets in a number-dependent manner. However, biofilm formation was inhibited as the plastic bracket was coated with saliva. For preventive treatments of WSL onset during orthodontic treatment, orthodontists should carefully select and customize brackets based on patient needs, goals, and biomechanical principles. This study developed a new measurement method using renG-expressing S. mutans UA159 to accurately assess active biofilm formation on bracket surfaces.

Electrochemical behaviour of tungsten nitride thin film in phosphate buffer saline solution for application in bioelectronics

ABSTRACT Micro-supercapacitor with tungsten nitride electrode has the potential to be used in bioelectronics for fast power supply. This study examines the electrochemical behaviour of magnetron-sputtered tungsten nitride (W2N) thin film in phosphate buffer saline (PBS) solution to evaluate their corrosion rate as electrodes in micro-supercapacitors used in bioelectronics. The electrochemical behaviour of W2N was analysed using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. The corrosion rate of W2N was compared with commercially pure titanium (CP-Ti) and magnetron-sputtered pure iron (Fe) film. Our results show that the corrosion current density of W2N was ∼6 times higher than CP-Ti and ∼2.5 times lower than Fe. Additionally, the charge transfer resistance of W2N was 18 times lower than that of CP-Ti and 1.3 times higher than Fe. Overall, the corrosion rate of W2N was significantly higher than CP-Ti and slightly lower than Fe. In summary, the findings suggest that W2N could be a potential candidate for micro-supercapacitor electrodes in bioelectronics. However, further studies are required to fully evaluate the biodegradation behaviour of W2N in vivo.

Interdigitated Gear-Shaped Screen-Printed Electrode Using G-PANI Ink for Sensitive Electrochemical Detection of Dopamine

In this research, a novel interdigitated gear-shaped, graphene-based electrochemical biosensor was developed for the detection of dopamine (DA). The sensor’s innovative design improves the active surface area by 94.52% and 57% compared to commercially available Metrohm DropSens 110 screen-printed sensors and printed circular sensors, respectively. The screen-printed electrode was fabricated using laser processing and modified with graphene polyaniline conductive ink (G-PANI) to enhance its electrochemical properties. Fourier Transform Infrared (FTIR) Spectroscopy and X-ray diffraction (XRD) were employed to characterize the physiochemical properties of the sensor. Dopamine, a neurotransmitter crucial for several body functions, was detected within a linear range of 0.1–100 µM, with a Limit of Detection (LOD) of 0.043 µM (coefficient of determination, R2 = 0.98) in phosphate-buffer saline (PBS) with ferri/ferrocyanide as the redox probe. The performance of the sensor was evaluated using cyclic voltammetry (CV) and Chronoamperometry, demonstrating high sensitivity and selectivity. The interdigitated gear-shaped design exhibited excellent repeatability, with a relative standard deviation (RSD) of 1.2% (n = 4) and reproducibility, with an RSD of 2.3% (n = 4). In addition to detecting dopamine in human serum, the sensor effectively distinguished dopamine in a ternary mixture containing uric acid (UA) and ascorbic acid (AA). Overall, this novel sensor design offers a reliable, disposable, and cost-effective solution for dopamine detection, with potential applications in medical diagnostics and neurological research.

A Robust RP-HPLC Method for Simultaneous Quantification, Validation and Stability Studies on Vildagliptin (VILD), Dapagliflozin (DAPA) and Metformin Hydrochloride (METF) in its Combined Dosage Formulation

Background: Vildagliptin, Dapagliflozin and Metformin Hydrochloride are anti- hyperglycemic agents. Anti-hyperglycemic agents are drugs that stimulate insulin secretion and lower the glucose level in the blood. They were investigated as a medication for Diabetes Mellitus (DM). Various studies have reported the HPLC, HPTLC, LC/MS methods for the estimation of individuals of VILD, DAPA and METF. However, until date stability indicating HPLC analysis method has not been reported for the estimation of VILD, DAPA and METF in combined glucagon secretion in a glucose-dependent manner. Introduction: The objective of present work was to develop and validate the stability of RPHPLC method for the estimation of Vildagliptin (VILD), Dapagliflozin (DAPA) and Metformin Hydrochloride (METF) in combined dosage form. Method: In this research work, High Performance Liquid Chromatography (HPLC) was used for validation in the chromatography. In the HPLC, Methanol and Potassium Dihydrogen phosphate buffer (85:15 v/v) were used as mobile phases. HPLC analysis was performed at 230 nm. The method was validated with different parameters such as linearity, precision, accuracy, specificity, and robustness, limit of detection (LOD) and limit of quantitation (LOQ). The RF values of VILD, DAPA and METF were 6.24 ± 0.05 min, 8.34 ± 0.05 min. and 3.68 ± 0.05 min, respectively. The accuracies of drug recovery were 0.6398 %,0.3680 %, 0.6398 % and over the range of 1–4 μg/ml, 20-80 μg/ml and 15-85 μg/ml of VILD, DAPA and METF, respectively. Results: Degradation products found in stress conditions did not interfere with the detection of VILD, DAPA and METF; therefore, the proposed technique can be considered stable. Significant degradation products of VILD, DAPA and METF were obtained in an acid at METF at 2.05 ± 0.05 min. (MDP-1) and degradation product for oxidation of METF at 2.11 ± 0.05 min. (MDP-2). When alkaline hydrolysis was conducted, photolytic and thermal conditions were applied alone or in combination with METF, no degradation product of VILD, DAPA and METF was found. Conclusion: The developed and validation method was satisfactorily applied for the analysis of pharmaceutical preparations and proved specific and accurate for quality control of the cited drugs in their combined dosage form.

Repeated intratracheal instillation effects of commonly used vehicles in toxicity studies with mice

Intratracheal instillation (ITI) is considered the most pragmatic approach for investigating the potential toxicities of various respiratory exposure materials. Various respiratory exposure materials, including nanomaterials, hazardous air pollutants, fine dust, and household biocides, have raised public health concerns because of limited toxicological information and increasing consumption. Hence, toxicity studies using ITI in laboratory animals are important to accurately assess the human risks associated with these respiratory-exposed materials. However, data to adequately support the study design of ITI toxicity studies, particularly those examining the effects of commonly used vehicles following repeated exposure are insufficient. Therefore, in this study, we examined the effects of 16 types of commonly used vehicles in toxicity studies following 14-day repeated ITI in mice. General health endpoints (mortality, clinical signs, and body weight) were monitored throughout the study period, and terminal endpoints (gross observation, lung weight, bronchoalveolar lavage fluid analysis, and lung histopathological examination) were assessed after terminal sacrifice. Saline and phosphate-buffered saline elicited the least response, whereas corn oil (50 µL) showed the most severe toxicity findings. In addition, several commonly used vehicles, including distilled water, sodium carboxymethyl cellulose, dimethyl sulfoxide, ethanol, Tween 20, and Tween 80, induced mild-to-severe toxicity in the respiratory system. Based on the results of this study, some commonly used vehicles in toxicity studies should be used with caution when the ITI exposure route is considered. These results provide important background information on the effects of vehicles in ITI toxicity studies along with valuable insights for designing toxicity studies using respiratory exposure materials.

Toll-like receptor 3 signaling attenuated colitis-associated cancer development in mice

Inflammatory bowel disease is associated with a high risk of colitis-associated cancer (CAC). We evaluated the role of TLR3 in CAC using a murine model. Wild-type (WT) and TLR3-knockout (TLR3−/−) mice received azoxymethane (AOM) 12.5 mg/kg intraperitoneally on day zero, followed by three cycles of 2% dextran sulfate sodium (DSS) for five days and free water for two weeks. We evaluated clinical indices, such as weight change, colon length, histological severity of colitis, and tumor number. We performed immunofluorescence assays for phospho-IκB kinase and β-catenin in colon tissues. To elucidate the antitumorigenic mechanism of TLR3 signaling, we injected poly(I: C) or phosphate-buffered saline intraperitoneally into an AOM/DSS-induced tumorigenesis model in WT mice. We also evaluate the direct antitumor effect of TLR signaling in AOM-treated WT and TLR3−/− mice without DSS. TLR3 deficiency increased tumor burden and colitis severity in the colon tissue than in the WT mice. β-catenin immunoreactivity was higher in TLR3−/− mice, while phospho-IκB kinase expression was similar. TLR3 activation by poly(I: C) did not reduce tumor burden in WT mice, but long-term AOM administration without DSS significantly increased tumor burden in TLR3−/− mice. TLR3 signaling attenuates CAC development, suggesting it may be a target for preventing CAC in inflammatory bowel disease.

Polymer-modified screen-printed electrode-based electrochemical sensors for doxorubicin detection

In the last decade, intensive research has been performed in the field of analytical electrochemistry, seeking designs of electrochemical sensors capable of providing better analytical characteristics in terms of sensitivity, selectivity, reliability, ease of fabrication and use, and low cost, especially for pharmaceutical drug monitoring. Our research has primarily focused on developing screen-printed electrode-based sensors and their application as electrochemical platforms for drug determination and monitoring, specifically emphasizing their suitability for surface modification. A commercial screen-printed graphene electrode was used as the electrochemical sensing component, which was subsequently modified with polymers, such as polyvinylidene fluoride and chitosan. All studied electrodes were tested using a doxorubicin hydrochloride (DOX) solution with a concentration of 0.002 mol L-1 dissolved in 0.1 mol L-1 phosphate-buffered saline at pH 6.7. Cyclic voltammetry was used as an electrochemical characterization technique to gather data on all tested electrodes' electrochemical activity. The morphological characterization of the electrodes was done using scanning electron microscopy. The changes in the electrolyte during the electrochemical measurements were followed through ultraviolet-visible spectroscopy. The modified electrodes demonstrated a favorable electrochemical response to DOX and exhibited higher electrical conductivity than the commercial one. The characterization results indicated that the Ch-modified electrode exhibited excellent electrochemical conductivity and demonstrated strong electrochemical performance. The evaluations of this electrode comprised the definition of the lowest limit of detection and limit of quantification among the tested electrodes, with values of 9.822 and 32.741 µmol L-1, respectively, within a linear concentration range from 1.5 to 7.4 µmol L-1. Additionally, the electrodes showed excellent repeatability, stability, and reproducibility, confirming their suitability for sensitive DOX detection.