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Present study was planned to investigate the ameliorative effect of silver nanoparticles (AgNPs) on acetaminophen-induced nephrotoxicity. Our results demonstrate that therapy of AgNPs at three different doses (50, 100 and 150 μg/kg once only) prevented the acetaminophen (2 g/kg once only) induced acute renal toxicity. AgNPs treated animals also show less intensity in the histological alterations in kidneys and corroborating the results of analysis of serum urea and creatinine. In addition, AgNPs therapy prevented the acetaminophen-induced oxidative stress, which was confirmed by the alleviated lipid peroxidation, enhanced renal reduced glutathione content and restored enzymatic activities of superoxide dismutase, catalase and adenosine triphosphatase in kidney. Thus, our results demonstrate a possible protective potential of AgNPs on renal toxicity induced by acetaminophen. This study will definitely lead to the development of therapeutic drug against nephrotoxicity, after further clinical and preclinical studies.

Medicines are usually prescribed for repeated use over shorter or longer times. Unfortunately, repeated-dose animal toxicity studies do not correlate well with observations in man. As emphasized by the ‘3Rs’ and the desire to phase-out animal research, in vitro models are needed. One potential approach uses clinostat-cultured 3D HepG2–C3A liver-mimetic spheroids. They take 18 days to recover in vivo physiological functionality and reach a metabolic equilibrium, which is thereafter stable for a year. Acute and chronic repeated-dose studies of six drugs (amiodarone, diclofenac, metformin, phenformin, paracetamol and valproic acid) suggest that spheroids are more predictive of human in vivo toxicity than either 2D-cultured HepG2 cells or primary human hepatocytes. Repeated non-lethal treatment results in a clear response and return to equilibrium. Mitochondrial toxic compounds can be identified using a galactose-based medium. Some drugs induced a protective (or stress) response that intensifies after the second treatment. This 3D spheroid model is inexpensive, highly reproducible and well-suited for the determination of repeated-dose toxicity of compounds (naturally or chemically synthesized).

Hepatic encephalopathy is a pathophysiological complication of acute liver failure, which may be triggered by hepatotoxic drugs such as acetaminophen (APAP). Although APAP is safe in therapeutic concentration, APAP overdose may induce neurotoxicity, which is mainly associated with oxidative stress. Caffeine is a compound widely found in numerous natural beverages. However, the neuroprotective effect of caffeine remains unclear during APAP intoxication. The present study aimed to investigate the possible modulatory effects of caffeine on brain after APAP intoxication. Mice received intraperitoneal injections of APAP (250 mg/kg) and/or caffeine (20 mg/kg) and, 4 h after APAP administration, samples of brain and blood were collected for the biochemical analysis. APAP enhanced the transaminase activity levels in plasma, increased oxidative stress biomarkers (lipid peroxidation and reactive oxygen species), promoted an imbalance in endogenous antioxidant system in brain homogenate and increased the mortality. In contrast, APAP did not induce dysfunction of the mitochondrial bioenergetics. Co-treatment with caffeine modulated the biomarkers of oxidative stress as well as antioxidant system in brain. Besides, survival assays demonstrated that caffeine protective effects could be dose- and time-dependent. In addition, caffeine promoted an increase of mitochondrial bioenergetics response in brain by the enhancement of the oxidative phosphorylation, which could promote a better energy supply necessary for brain recovery. In conclusion, caffeine prevented APAP-induced biochemical alterations in brain and reduced lethality in APAP-intoxicated mice, these effects may relate to the preservation of the cellular antioxidant status, and these therapeutic properties could be useful in the treatment of hepatic encephalopathy induced by APAP intoxication.

Disposable electrochemical sensors using sustainable and cheap materials are an exciting alternative to produce new kinds of sensing platforms. Waterproof paper (WP) is a biodegradable and biocompatible material that allows dropped of the sample on its surface without absorption by fibers. Also, WP can be used for miniaturized sensors construction. In this work, a conductive ink was produced with nail polish and graphite powder, using the WP as the sensor substrate for paracetamol (PAR) and melatonin (MEL) voltammetric determination. PAR is a pharmaceutical commonly used in high doses for the relief of pain and fever, and MEL is a hormone related to several diseases besides a direct relation to sleep quality. Using differential pulse voltammetry for PAR determination, the WP sensor showed a linear response in the concentration ranging from 0.50 μmol L−1 to 100 μmol L−1 with a limit of detection (LOD) of 53.6 nmol L−1. Square wave voltammetry was applied for MEL determination, and the proposed electrode presented linear response ranging from 0.80 μmol L−1 to 100 μmol L−1 and LOD of 32.5 nmol L−1. The sensor showed excellent repeatability and reproducibility for consecutive measurements. Then, the disposable WP sensor was successfully applied in the determination of PAR and MEL in pharmaceutical and biological samples, with recovery values, above 91.1%. The described architecture allowed the manufacture of a disposable, simple, and low-cost electroanalytical device that can be used for electrochemical sensing.

This paper presents a simple and low-cost method for patterning poly(dimethylsiloxane) (PDMS) barriers in porous support such as paper for the construction of flexible microfluidic paper-based analytical devices (μPADs). The fabrication method consisted of contact-printing a solution of PDMS and hexane (10:1.5 w/w) onto chromatographic paper using custom-designed rubber stamps containing the patterns of μPADs. After penetrating the paper (∼30 s), the PDMS is cured to form hydrophobic barriers. Under optimized conditions, hydrophobic barriers and hydrophilic channels with dimensions down to 949±88 μm and 771±90 μm (n=5), respectively, were obtained. This resolution is well-suitable for most applications in analytical chemistry. Chemical compatibility studies revealed that the PDMS barriers were able to contain some organic solvents, including acetonitrile and methanol, and aqueous solutions of some surfactants. This find is particularly interesting given that acetonitrile and methanol are the most used solvents in chromatographic separations, non-aqueous capillary electrophoresis and electroanalysis, as well as aqueous solutions of surfactants are suitable mediums for cell lyses assays. The utility of the technique was evaluated in the fabrication of paper-based electrochemical devices (PEDs) with pencil-drawn electrodes for experiments in static cyclic voltammetry and flow injection analysis (FIA) with amperometric detection, in both aqueous and organic mediums.

A new ambient ionization method allowing the direct chemical analysis of living human body by mass spectrometry (MS) was developed. This MS method, namely Megavolt Electrostatic Ionization Mass Spectrometry, is based on electrostatic charging of a living individual to megavolt (MV) potential, illicit drugs, and explosives on skin/glove, flammable solvent on cloth/tissue paper, and volatile food substances in breath were readily ionized and detected by a mass spectrometer.

Background: Dried blood spot (DBS) sampling, the collection of whole blood samples on paper, is being evaluated for its use in quantitative analysis. The aim of this investigation was to evaluate the impact of sample hematocrit (HCT) and punch location on assay bias in the measurement of compounds with varying physicochemical properties, when a portion of a DBS sample is analyzed. In addition, the statistical significance of factors such as compound, card type, HCT level, spot position on a card and the location of the punch on the spot were evaluated. Results: The results of this work indicate that for quantitative analysis using a portion of the DBS, notable bias (>15%) exists due to the effect of HCT and nonhomogeneous distribution of compound across the spot. The statistical analysis of results from a split-split-plot designed study showed that the factors of compound, card type and HCT were statistically significant (p < 0.05) both individually and in complex interactions, which affect the accuracy of quantitative concentrations obtained from DBS samples for each compound on each card type. Conclusion: To achieve the acceptance criteria (±15%) for accuracy when removing a portion of the DBS spot for quantitative analysis, HCT and punch location for each selected card type will need to be assessed during validation and sample analysis.

Medicines are most often oral solid dosage forms made into tablets or capsules, and there is little room for individualized doses. The drug substance and additives are processed through multiple production phases, including complex powder handling steps. In drug manufacturing, the control of the solid-state properties of active pharmaceutical ingredient (API) is essential and it offers opportunities for enhancement of drug delivery systems. In this context, inkjet printing technologies have emerged over the last decades in pharmaceutical and biological applications and offer solutions for controlling material and product characteristics with high precision. Here we report the concept of conventional inkjet printing technology to produce printable pharmaceutical dosage forms on porous substrates. Data are shown to demonstrate inkjet printing of APIs into paper substrates, and how the model drug substances (paracetamol, theophylline, and caffeine) are penetrating the porous substrates used. The method enables controlling not only the deposition but also the crystallization of the drug substances. We anticipate that the inkjet printing approach has immense potential in making sophisticated drug delivery systems by use of porous substrates in the future. For example, it may offer new perspectives for solving problems around poorly soluble drugs and dosing low-dose medicines accurately. Furthermore, with the advent of genetic mapping of humans, controlled inkjet dosing can bring solutions to fabricate on-demand individualized medicines for patients. © 2011 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:3386–3395, 2011

The present work describes the construction and application of a simple, low cost and sensitive microfluidic paper-based device with electrochemical detection for the detection of paracetamol and 4-aminophenol. The separation channels of a width of 2.0 mm were created on paper using a wax printing process to define the regions of the device. A baseline separation level of the analytes can be obtained in 0.1 mol L(-1) acetate buffer solution at pH 4.5 and by injecting 500 nL of the standard solutions at 12 mm from the working electrode. The electrochemical detection system was created at the end of the channels through a process known as sputtering. The previously separated analytes were detected at the end of the hydrophilic separation channel by applying a potential of 400 mV vs. pseudo Au on the working electrode. Experimental variables such as type of paper (cation exchanger and n1), pH, sample volume, applied potential and distance of sample injection were evaluated and, under the conditions of higher response, it was possible to obtain detection limits of 25.0 and 10.0 μmol L(-1) for paracetamol and 4-aminophenol, respectively.

Background: As hematocrit levels are known to vary between individuals and with disease state, its effect on the physical characteristics of dried blood spot (DBS) samples and on the accurate quantification of analytes within these samples is examined. Results: The area of DBS samples decreases with increasing hematocrit levels in a linear manner on the three cellulose paper substrates tested. Furthermore, a bias was observed in the concentrations of two analytes determined in DBS samples at different hematocrits, which in some cases exceeded acceptable values, particularly for hematocrits outside normal values. Conclusion: If it is expected that the hematocrit of study samples will vary from values considered normal, then its effect on the quantitative determination of an analyte in DBS samples should be investigated as part of the method development and validation. If an unacceptable effect is observed, then this will need to be addressed, by modification of the analytical method, or the inclusion of quality control samples at different hematocrit levels to show control of the assay.

A number of hydroxamic acids have been synthesized and investigated as laccase-mediators for pulp bleaching. As compared with N-hydroxyacetanilide (NHA), one of the most effective laccase-mediators reported so far, N-(4-cyanophenyl)acetohydroxamic acid (NCPA), resulted in the highest brightness and lowest kappa number of hardwood kraft pulp of all the laccase-mediators studied. The bleaching efficacy of a laccase/7-cyano-4-hydroxy-2H-1,4-benzoxazin-3-one system was also comparable with that of a laccase/NHA system. A laccase/NCPA system was further studied for the bleaching of unbleached softwood kraft pulp. The effects of pulp consistency, laccase dosage, NCPA dosage, incubation time, and oxygen pressure on the bleaching efficacy of a laccase/NCPA system were studied.