Spectrophotometric Determination of Nitrite in Water Samples with 4‐(1‐Methyl‐1‐Mesitylcyclobutane‐3‐yl)‐2‐Aminothiazole

Naringin-loaded Arabic gum/pectin hydrogel as a potential wound healing material

Wound healing is a complicated cellular process with overlapping phases. Naringin (NAR); a flavanone glycoside, possesses numerous pharmacological effects such as anti-inflammatory, antioxidant and anti-apoptotic effects. In the current study, Arabic gum (AG)/pectin hydrogel was utilized to encapsulate NAR. Drug-loaded AG/pectin hydrogel exhibited excellent EE% of about 99.88 ± 0.096 and high DL% of about 16.64 ± 0.013. The formulated drug-loaded hydrogel was characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Zetasizer analyzer, besides determination of equilibrium degree of swelling (EDS%). Afterwards, wound healing potential of NAR-loaded AG/pectin hydrogel was evaluated in an in vivo animal model. Results manifested that NAR-loaded AG/pectin hydrogel was able to accelerate wound healing in terms of enhanced angiogenesis, re-epithelialization and collagen deposition. Furthermore, it significantly (P < 0.001) down-regulated the mRNA expression of inflammatory mediators (TNF-α) and apoptosis (BAX). In addition, NAR-loaded AG/pectin hydrogel was found to possess potent antioxidant activity as it enhanced the levels of SOD and GSH, besides decreasing the levels of MPO, MDA and nitrite. These data suggest that NAR-loaded AG/pectin hydrogel could be utilized in wound healing applications.

Hybrid lipid core chitosan-TPGS shell nanocomposites as a promising integrated nanoplatform for enhanced oral delivery of sulpiride in depressive disorder therapy

Sulpiride (SUL), a benzamide derivative, acts as a multitarget drug with extensive biological properties. However, being a P-glycoprotein efflux substrate with a limited oral bioavailability imposes a challenge to its clinical efficacy. The current research explores the impact of tailored hybrid lipid-polysaccharide nanocomposites in augmenting the biological performance of SUL. Chitosan-graft-tocopherol polyethylene glycol 1000 succinate (TPGS) copolymers were synthesized and integrated as a polysaccharide shell into a SUL-loaded lipid nanocore. The optimized nanohybrids revealed a nanocore-shell structure with 110.1 nm particle size, 23.7 mV zeta potential, 85.42% encapsulation efficiency, a pH-dependent-release profile, and an acceptable mucoadhesive tendency. Employing TPGS into the chitosan backbone alleviated the cellular internalization of nanohybrids into the Caco-2 intestinal cells and hence increased the intestinal permeation and the oral bioavailability of SUL by 3.3, and 8.7-folds, respectively. Reserpine-induced depression rat model confirmed the superior antidepressant activity of nanohybrids, compared with free SUL and a marketed product. The nanohybrids exhibited 1.87- and 1.47-folds enhancement in both serotonin and dopamine levels, respectively. Additionally, nanohybrids were shown to attenuate brain oxidative stress state and SUL irritant effect on different body tissues. Overall, the newly tailored nanohybrids pave the way for an advance in the field of oral drug delivery.

A Simple and Rapid Spectrophotometric Method for Nitrite Detection in Small Sample Volumes

A simple, rapid, and environmentally-friendly spectrophotometric method for nitrite detection was developed. Detection was based on a redox reaction with iodide ions in an acidic condition. The reaction was evaluated by detecting the increase in absorbance of the colored product of iodine at 362 nm wavelength. To obtain a good spectrophotometric performance, the iodide ions concentration, hydrochloric acid concentration, and reaction time were optimized. In the optimal condition, the developed spectrophotometric method provided a linear range of 0.0625 to 4.00 mg L−1 (r = 0.9985), reaction time for 10 min, a limit of detection of 25 µg L−1, and a limit of quantitation of 85 µg L−1. This method showed good repeatability (RSD < 9.21%), high sample throughput (9 samples min−1), and good accuracy (recovery = 88 ± 2 to 99.5 ± 0.4%). The method has the potential to be used in crime scene investigations as a rapid screening test for gunshot residue detection via nitrite detection.

Precisely Fabricated Sulpiride-Loaded Nanolipospheres with Ameliorated Oral Bioavailability and Antidepressant Activity

BACKGROUND

Sulpiride (SUL), is a selective antidopaminergic drug that had extensive biological activities. However, its sparingly aqueous solubility and limited gastrointestinal permeability lead to scanty oral bioavailability which hinders its clinical efficacy.

OBJECTIVE

SUL-loaded lipospheres (SUL-LPS) were designed to serve as an oral biocompatible nanovector for improving SUL permeability as well as conquering its low oral absorption and then in turn enhancing its antidepressant action.

METHODS

SUL-LPS were fabricated via two processing techniques namely, melt emulsification and solvent evaporation. The impact of different lipid cores, phospholipid shells together with various surfactant concentrations and types on the lipospheres properties were screened. Detailed physicochemical elucidations were performed followed by ex vivo permeation appraisal using the non-everted intestine model. The pharmacokinetic parameters of SUL-LPS, free SUL and marketed product were assessed following oral administration to healthy rats. Reserpine-induced depression rat model was used to assess the antidepressant action of SUL-LPS on which full behavioural and biochemical analysis was conducted. Safety attributes of nanoencapsulated SUL on the brain and other internal organs were evaluated.

RESULTS

The optimum LPS revealed an excellent nanosize with a narrow PdI, negative zeta potential and acceptable entrapment efficiency of 68.62 nm, 0.242, -30.4 mV and 84.12%, respectively. SUL-LPS showed a sustained release pattern and 2.1-fold enhancement in the intestinal permeation parameters with low mucin interaction. Oral pharmacokinetic appraisal exhibited that LPS provided 3.4-fold improvement in SUL oral bioavailability together with long-circulating properties, relative to the free drug. Pharmacodynamic study confirmed the superior antidepressant action of SUL-LPS as evident by 1.6 and 1.25-fold elevation in the serotonin and dopamine expressions, respectively. Meanwhile, nanotoxicological appraisal proved the biocompatibility of SUL-LPS upon repetitive oral administration.

CONCLUSION

Rationally designed lipospheres hold promising in vitro and in vivo characteristics for efficient delivery of SUL with high oral bioavailability, antidepressant activity together with a good safety profile.

Chitosan-stabilized selenium nanoparticles attenuate acrylamide-induced brain injury in rats

Acrylamide (ACR) is produced during food processing and has been shown to cause health problems. Selenium, especially in its nanoscale, is an important trace element in human nutrition. Chitosan-stabilized selenium nanoparticles (Ch-SeNPs) stability and its protective potential against ACR-induced injury in rats were evaluated. Ch-SeNPs displayed high radical-scavenging activity and reducing power that were not significantly changed for 60 days at 4°C. The transmission electron microscopy images and dynamic light scattering results demonstrated high stability of Ch-SeNPs during storage. ACR (20 mg kg-1 day-1) led to elevate the level of malondialdehyde, dopamine and noradrenaline in blood serum, and cerebral cortex. Ch-SeNPs (0.2 mg kg-1 day-1) displayed more protection against ACR-induced damages comparing to Na2SeO3. More than 90% of the glutathione pool in the brain tissue was in reduced form. Correlation coefficient analysis demonstrated the attenuating effect of Ch-SeNPs against ACR-induced brain-injury and hormone imbalance. Administrating Ch-SeNPs 15 days before ACR-treatment is required for obtaining the best protection. PRACTICAL APPLICATIONS: Ch-SeNPs used in the present study characterized by its high storage stability for two months without losing its antioxidant potential. After conducting toxicity tests, it is suggested to supplement some foods with Ch-SeNPs because of its high antioxidant potential and significant protection ability against the oxidative stress damages in living organisms. These advantages may nominate the Ch-SeNPs for several industrial applications in the field of food processing and protection.

A simple yet sensitive colorimetric nitrite ions assay based on diazotization with p‑Aminobenzoic and coupling with phloroglucinol in acidic medium

Immoderate intake of nitrite (NO₂^-) is deleterious human health and may result in causing dangerous diseases. In this study, nitrite detection system was successfully fabricated based on a unique diazo-coupling reaction of p‑Aminobenzoic acid (PABA) and phloroglucinol (1, 3, 5‑trihydroxybenzene). Upon the presence of NO₂^- in an acid medium, p‑Aminobenzoic acid could not only form diazonium ion easily but also couple with p‑Aminobenzoic acid, and results forming yellow water-soluble azo dye that shows maximum absorption at 434 nm. Under the further accurate determination condition, such as acid concentration, amount of reagents and time required, the naked-eye detection of NO₂^- showed excellent selectivity in compared with some anions. Especially, diazotization and coupling reaction proposed here is very fast and control of pH and temperature are unnecessary. Moreover, the color is stable for several days and Beer's law is obeyed over a wide range. Reliable detection can be made in the range of 0.05 to 1 p.p.m. of nitrite ion. Detection limit was calculated to be 0.024 p.p.m. (0.52 μ M) by UV-visible spectroscopy and 0.05 p.p.m. (1.09 μ M) by naked-eye. By using an electrochemical method, IR, SEM, and ¹HNMR, the sensing mechanism can be easily verified. More importantly the proposed method was successfully applied for the determination of nitrite in a real water sample.

Disposable manganese oxide screen printed electrodes for electroanalytical sensing

Manganese dioxide screen printed graphite electrodes for electro-analytical sensing purposes have been fabricated. The prepared sensors exhibit attractive performances as electro-catalysts for the sensing of nitrite ions and ascorbic acid with detection limits comparable or lower than those obtainable with other electrochemical sensors. The manganese dioxide platforms are also explored towards the electrochemical reduction of oxygen which has importance in electrochemical energy storage. While the platforms are found to operate by a four-electron reduction producing water (rather than hydrogen peroxide which is undesirable), a large overpotential, compared to other possible electrode compositions reported in the literature, is required. Nevertheless, the promising results towards the electro-analytical sensing of nitrite ions and ascorbic acid and also given the disposable nature and scale of economies make these electrodes useful as sensor platforms.

A simple and sensitive spectrophotometric method for the determination of trace amounts of nitrite in environmental and biological samples using 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt

A very simple, sensitive, fairly selective and rapid spectrophotometric method for the determination of trace amounts of nitrite has been described. This method is based on the diazotized intramolecular coupling of electrophilic diazonium cation with the phenolic group of 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt (AHNDMS) in a phosphate buffer solution of pH 7.5. The cyclic product has a purple color with maximum absorbance at 560nm and is stable for 6h. Optimum reaction conditions and other important analytical parameters for the maximum color development were established. Beer's law was found to obey for nitrite in the concentration range of 0.1-1.6microgml(-1) with molar absorptivity of 2.6x10(4)lmol(-1)cm(-1) and Sandell's sensitivity of 0.0075microgml(-1). The effect of interfering ions on the determination is described. The recommended method was applied for the determination of nitrite in different water, soil and human saliva samples. The performance of the recommended method was evaluated in terms of Student's t-test and variance ratio F-test, which indicated the significance of proposed method over the reference method.

Manganese Dioxide Graphite Composite Electrodes: Application to the Electroanalysis of Hydrogen Peroxide, Ascorbic Acid and Nitrite

The modification of carbon powder with manganese dioxide using a wet impregnation procedure with electrochemical characterisation of the modified powder is described. The process involves saturation of the carbon powder with manganese(II) nitrate followed by thermal treatment at ca. 773 K leading to formation of manganese(IV) oxide on the surface of the carbon powder. The construction of composite electrodes based on manganese dioxide modified carbon powder and epoxy resin is also described, including optimisation of the percentage of the modified carbon powder. Composite electrodes showed attractive performances for electroanalytical applications, proving to be suitable for the electrochemical detection of hydrogen peroxide, ascorbic acid and nitrite ions with limits of detection comparable to the detection limits achieved by other analytical techniques. The results obtained for detection of these analytes, together with composite electrodes flexible design and low cost offers potential application of composite electrodes in biosensors.