Buffer pH Research Articles

A UPLC Method for Simultaneous Estimation of Trastuzumab and Hyaluronidase in Bulk and Pharmaceutical Dosage Form

Objective: The proposed research aimed at establishing a quick, accurate, and exact ultra-performance liquid chromatography (UPLC) methodology for contemporaneously analyzing trastuzumab and hyaluronidas in bulk and pharmaceutical formulation, with a focus on the stability-indicating properties of the assay. Method: Using a Water X-Bridge C18 column (50 mm x 4.6 mm x 2.5 μ) and a mobile phase of ACN: Buffer (pH 2.5) [50% v/v], pushed at 0.5 mL/min, compounds were separated chromatographically. An ultraviolet (UV) detector fixed at 260 nm was employed to identify the isolated compounds. Results: The findings showed that 1.3529 and 2.404 minutes were optimal for separating Trastuzumab and Hyaluronidase, correspondingly. The current procedure has been verified in accordance with ICH standards Q2 R1, and stability-indicating tests have been performed in accordance with ICH standards Q1A R2. Both the intra- and inter-day precisions were determined to be satisfactory. The suggested approach showed linearity between 30 to 180 μg/mL of trastuzumab and between 12.50-75μg/ mL of hyaluronidase. It was determined that the limit of detection (LoD) and limit of quantitation (LoQ) for trastuzumab were 0.36 and 1.2 μg/mL, correspondingly, whereas those for hyaluronidase were 0.15 and 0.5 μg/mL. The approach was shown to have a recovery rate around 98.6 to 99.7%. Conclusion: The suggested approach successfully separated the chemical compounds from their by-products. Therefore, trastuzumab and hyaluronidase routine evaluation and stability-indicating tests were both effectively implemented using the approach.

Structure–Function Relationship and Stability of Latroeggtoxin‐VI: A Proteinaceous Toxin From the Eggs of Latrodectus tredecimguttatus

ABSTRACTLatroeggtoxin‐VI (LETX‐VI), a peptide toxin discovered from the eggs of spider Latrodectus tredecimguttatus, was previously shown to promote the synthesis and release of dopamine in rat pheochromocytoma (PC12) cells, showing potential applications in the neurobiology and medicine. To further understand the structure and properties of LETX‐VI, the key residues were identified and their roles in the structure, function, and stability of LETX‐VI were analyzed in the present work. Based on the protein molecular docking, our previous work, and the relevant literature, the potential key residues of LETX‐VI were selected and identified by alanine‐scanning mutagenesis. The wild‐type LETX‐VI and its 13 mutants, including a double mutant, were prepared by gene cloning and heterologous expression in Escherichia coli, followed by activity, structure, and stability determination. The results demonstrated that the activity of the mutants K25A, R35A, K40A/R41A, and L45A, particularly R35A, to promote dopamine release from PC12 cells was significantly decreased compared with that of the wild‐type LETX‐VI, indicating that these mutated residues are the key residues. Circular dichroism (CD) analysis showed that the secondary structure of these mutants was not obviously different from that of wild‐type LETX‐VI, suggesting that mutation‐caused decrease in the activity of LETX‐VI is due to the changes in the binding site on the molecule surface, rather than the abnormal alternation of the molecular conformation of LETX‐VI. Acetonitrile (ACN) did not obviously influence the activity of LETX‐VI; however, 0.1% trifluoroacetic acid (TFA) treatment for 2 h significantly reduced its activity. Treatment with weakly acidic and basic buffers (pH ≥ 6.6) for 12 h was favorable for LETX‐VI and R35A to exert their activity. Higher temperatures (>37°C) decreased the activity of both wild‐type LETX‐VI and R35A. In conclusion, K25, R35, K40, R41, and L45 particularly R35 are the important functional site residues; during experiments, care should be taken to avoid the adverse influence of strong acid and high temperature on LETX‐VI. These observations have enhanced our understanding of the structure and properties of LETX‐VI and provided references for the subsequent modification of structure and function of LETX‐VI.

Anti-hyperglycemic Activity of the Piper longum Dried Fruit Extract on the Experimental Animal Model

Predominately, in the Indian tradition, the species Piper longum could play a significant role in the management of several severe disorders such as asthma, tuberculosis, rheumatism, and epilepsy. Mostly, the plant root would be responsible for treating insomnia, rheumatism, and epilepsy, as well as plant leaves for a prevailing stimulant for both the digestive and the respiratory systems. The alcoholic extract of P. longum fruits showed antiamoebic, anti-inflammatory, and immunomodulatory potential in experimental animals. In addition to these benefits, the current study concluded that the examination of the ethanolic extract of P. longum fruits as an anti-hyperglycemic in streptozotocin (STZ)-induced diabetic animal model (Wistar rats). A diabetic condition could be induced in an animal model by dissolving STZ in a 0.1 M citrate buffer of pH 4.5. It was injected intraperitoneally at a dose of 50 mg/kg body weight in the animal test model. All the test animals were fed with a 5% dextrose solution to control overnight hypoglycemic conditions. Subsequently, 48 hours of hyperglycemic test animals were selected for the study. The observed anti-hyperglycemic effect of ethanolic extract of P. longum dried fruits should correspond to that of the reference standard, i.e., glibenclamide. The study reveals that the ethanolic extract of P. longum fruits has a promising potential as an anti-hyperglycemic in the STZ-induced diabetic animal test model. So, it is presumed that the ethanolic extract of P. longum could be a promising alternative for severe diabetes complications such as hyperglycemia, oxidative stress, etc., in the near future

Optimized Extraction and Characterization of Allicin from Snow Mountain Garlic and its Anticancer Potential via Allicin-loaded CuO Nanoparticles

This study aimed to optimize the extraction and purification of allicin and to characterize allicin-loaded CuO nanoparticles for potential anticancer applications. Initially, various solvents, including MilliQ water, methanol at different concentrations, and phosphate buffer at varying pH levels, were tested to maximize the yield and purity of allicin. The extraction efficiency was evaluated by measuring the absorbance at 244 nm using UV spectrophotometry. The highest extraction efficiency was achieved with MilliQ water (0.92 ± 0.03) and 40% methanol (0.89 ± 0.05). Additionally, phosphate buffer pH 2.5 in 40% methanol also demonstrated good efficiency (0.86 ± 0.04). Following extraction, the allicin was purified using a glass column to remove impurities, ensuring a high degree of purity for subsequent applications. The chemical structure and purity of the purified allicin were confirmed using fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). To enhance the stability and bioavailability of allicin, allicin-loaded CuO nanoparticles were formulated. Dynamic light scattering (DLS) analysis revealed a mean particle size of 125 nm, while zeta potential measurements indicated a surface charge of -21.74 mV, suggesting good stability. Scanning electron microscopy (SEM) provided detailed insights into the morphology and structure of the nanoparticles. The successful optimization of allicin extraction and purification, coupled with the characterization of allicin-loaded nanoparticles, paves the way for their potential application in cancer therapy. The enhanced stability and bioavailability of allicin through nanoparticle formulation hold promise for improving its therapeutic efficacy against cancer. Further studies are warranted to explore the anticancer activity of these nanoparticles in biological systems.

Development of a Robust and Reliable RP-HPLC Method for the Estimation of Finerenone in Tablet Dosage Form

An advanced analytical method was explored, specifically tailored for estimating finerenone, a vital drug found in tablet formulations intended to reduce the risk of chronic kidney disease in patients with type-2 diabetes. This sophisticated technique employs an Inertsil ODS 3V C18 column (5 μm particle size x 250 x 4.6 mm) for precise separation of analyte. The mobile phase consists of an ammonium dihydrogen phosphate buffer (pH 4.5) and acetonitrile (60:40), which is a carefully balanced mixture that flows consistently at 1.0 mL/min. UV detection is achieved at a wavelength of 238 nm. Finerenone’s characteristics are unveiled with a brief retention time of 4.06 minutes, highlighting the efficiency of the method. The method demonstrates linearity within the concentration range of 2.5 to 15 μg/mL, offering a comprehensive scope for accurate analysis. This robust reversed-phase high-performance liquid chromatography (RP-HPLC) method undergoes thorough validation following International Council for Harmonisation (ICH) guidelines, ensuring its reliability. Notably, the accuracy is impressive, with a mean recovery falling comfortably within the acceptable range of 99.76 to 101.09%. In summary, our analytical approach stands out for its simplicity, precision, sensitivity, rapidity, and robustness in estimating finerenone in tablet formulations.

Formulation Optimization and Evaluation of Herbal Films Containing Ethanol Leaves Extract of Cassia auriculata to Treat Chronic Constipation Disorder

An intriguing trend in recent years has been the designing of oral films containing extracts from medicinal plants. Therefore, efforts were made in the current work to create fast-dissolving herbal films using Cassia auriculata ethanol leaf extract in order to create a dosage form that would be more convenient to administer and treat chronic constipation disorders in the elderly. Varying ratios of hydroxy propyl methyl cellulose as polymer, propylene glycol as film softener, and a solvent-casting approach were utilized to create the quickly dissolving herbal films of C. auriculata leaf extract. A number of quality control measures, including weight fluctuation, thickness variation, surface pH, percentage moisture uptake, percentage moisture loss, disintegration time and folding endurance, were assessed. According to the findings, every film had a decent appearance, a smooth texture, was free of particle matter, and had excellent folding endurance. According to a content uniformity analysis, the drug is dispersed evenly across the entire film, and each one dissolves in less than 95 seconds. In-vitro dissolving studies using Paddle type apparatus in pH 6.8 phosphate buffer pH 6.8, which is simulated saliva, were performed for each film composition. Out of all nine formulations, formulation F5, which is an herbal film with 10% propylene glycol and 40% HPMC, exhibited complete drug release (99.6%) in 30 minutes and had a strong folding endurance value. The release of medication from films was found to follow a first-order kinetics. Overall, studies indicate that the most feasible dose form that can be used in medical settings for the treatment of chronic constipation disorder is fast-dissolving herbal films containing C. auriculata leaves extract. This is especially true for patients who have difficulty swallowing.

Enhancing Anticancer Potential: Optimization of Allicin Extraction from Regular Garlic and Characterization of Allicin-Loaded Copper Oxide Nanoparticles

This research aimed to optimize the extraction and purification processes of allicin from regular garlic (Allium sativum) and to evaluate the potential of allicin-loaded copper oxide (CuO) nanoparticles for anticancer applications. Initially, various solvents, including MilliQ water, 25% methanol, and phosphate buffer pH 2.5 in 60% methanol, were tested to determine the most effective conditions for extracting allicin. Among these, MilliQ water and 25% methanol demonstrated the highest extraction efficiencies, as evidenced by their absorbance values. The extracted allicin underwent purification and was subsequently characterized using fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). These techniques confirmed the identity and high purity of the allicin. Following purification, the allicin was encapsulated into copper oxide (CuO) nanoparticles using an optimized nanoprecipitation protocol. The physicochemical properties of the allicin-loaded nanoparticles were thoroughly characterized. Dynamic light scattering (DLS) analysis revealed a mean particle size of 123 nm, indicating a uniform and nanoscale particle distribution. Zeta potential measurements indicated a surface charge of -28.34 mV, suggesting good stability of the nanoparticles in suspension. Scanning electron microscopy (SEM) was employed to further analyze the particle size, surface charge, and morphology, providing detailed insights into the structural attributes of the nanoparticles. The successful encapsulation of allicin into CuO nanoparticles not only enhances the stability and bioavailability of allicin but also leverages the unique properties of CuO nanoparticles, which are known for their anticancer, antioxidant, and antimicrobial activities. This study underscores the potential of allicin-loaded CuO nanoparticles derived from regular garlic as a promising formulation for pharmaceutical applications, particularly in the field of oncology. These findings warrant further investigation into their clinical efficacy and safety to fully harness their therapeutic potential.

β-galactosidase immobilization on ceramic ultrafiltration membrane for simultaneous lactose hydrolysis and protein separation

Protein and lactose of cheese whey can be separated using ultrafiltration membranes and lactose can be hydrolyzed by β-galactosidase. This study investigated the integration of ultrafiltration and enzymatic hydrolysis for simultaneous protein concentration and lactose hydrolysis. β-galactosidase was immobilized on ceramic membrane via surface activation with gelatin and subsequent enzyme cross-linking with glutaraldehyde. Membrane geometries, buffer types, gelatin and enzyme concentrations were optimized. The optimal results yielded a 63 % enzyme immobilization efficiency and a 93 % lactose hydrolysis rate by using disc membrane, sodium acetate buffer (pH 4.8), sodium phosphate buffer (pH 7.5), 0.1 g/L gelatin concentration, and 5.0 g/L enzyme concentration. The optimized enzymatic membrane was evaluated with synthetic and real whey. In synthetic whey, 85 % lactose hydrolysis and 89 % protein rejection were achieved. While in real whey, 72 % lactose hydrolysis and 83 % protein recovery were obtained. This approach offers a single-step, efficient, and scalable method for whey valorization with potential for industrial applications.

Retention mechanism in combined hydrodynamic and slalom chromatography for analyzing large nucleic acid biopolymers relevant to cell and gene therapies

Slalom chromatography (SC) was discovered in 1988 for analyzing double-stranded (ds) DNA. However, its progress was impeded by practical issues such as low-purity particles, sample loss, and lack of a clear retention mechanism. With the rise of cell and gene therapies and the availability today of bio-inert ultra-high-pressure liquid chromatography (UHPLC) columns and systems, SC has regained interest. In SC, the elution order is opposite to that observed in hydrodynamic chromatography (HDC): larger DNA molecules are more retained than small ones. Yet, the underlying SC retention mechanism remains elusive.We provide the physicochemical background necessary to explain, at a microscopic scale, the full transition from a HDC to a SC retention mechanism. This includes the persistence length of the DNA macromolecule (representing DNA stiffness), their relaxation time (τR) from the non-equilibrium contour length to the equilibrium entropic configuration, and the relationship between the mobile phase shear rate (〈γ̇〉) in packed columns and the DNA extended length. We propose a relevant retention model to account for the simultaneous impact of hydrodynamic chromatography (HDC) and SC on the retention factors of a series of large and linear dsDNAs (ranging from 2 to 48 kbp). SC data were acquired using bio-inert MaxPeakTM Columns packed with 1.7μm BEHTM 45 Å, 1.8μm BEH 125 Å, 2.4μm BEH 125 Å, 5.3μm BEH 125 Å, and 11.3μm BEH 125 Å Particles, an ACQUITYTM UPLCTM I-class PLUS System, and either 1 × PBS (pH 7.4) or 100 mM phosphate buffer (pH 8) as the mobile phase. SC is a non-equilibrium retention mode that is dominant when the Weissenberg number (Wi=〈γ̇〉τR) is much larger than 10 and the average extended length of DNA exceeds the particle diameter. HDC, on the other hand, is an equilibrium retention mode that dominates when Wi<1 (DNA chains remaining in their non-extended configuration). Maximum dsDNA resolution is observed in a mixed HDC-SC retention mode when the extended length of the DNA is approximately half the particle diameter. This work facilitates the development of methods for characterizing various plasmid DNA mixtures, containing linear, supercoiled, and relaxed circular dsDNAs which all have different degree of molecular stiffness.

Effect of Temperature on the Removal of Interferences in the Voltammetric Procedure for the Determination of Cr(VI).

The aim of this paper was to investigate the effect of temperature on the removal efficiency of surfactant-induced interferences. Surfactants were removed as a result of mixing with XAD-7 resin. The study was carried out using the example of Cr(VI) determination by adsorption stripping voltammetry (AdSV). Measurements were carried out using a solution containing Cr(VI), acetate buffer (pH = 6.2), DTPA, KNO3, and different surfactants. Ten mL of the solution was mixed with 0.5 g of XAD-7 resin at different temperatures for 5 min prior to voltammetric measurement. The effect of the mixing temperature of the sample with the resin on the voltammetric Cr(VI) signal in the presence of different surfactants was studied in the range from 20 to 60 °C. The proposed method of removing interference from surfactants by mixing the sample with the XAD-7 resin at 60 °C was used for the determination of trace amounts of Cr(VI) in river water containing non-ionic, anionic, cationic surfactants, and biosurfactants.

Dual-responsive, highly bacteriostatic and swellable chitosan-based hydrogels loaded with 5-fluorouracil for sustainable release

In this work, a dual-responsive hydrogel for sustainable release of drug was prepared using chitosan grafted with PBA as substrate to form semi-interpenetrating polymer networks (S-IPN) via free-radical crosslinking polymerization of acrylic acid in the presence of MBAA as a crosslinker and KPS as an initiator as well as Fe3+.ions introduced. The results from comprehensive characterization indicated that the as-prepared hydrogel possesses cavity structure with the pores of varying sizes, thus facilitating the accommodation of 5-fluorouracil as a model drug. In addition, the swelling behavior of the hydrogels in different pH buffers and glucose solutions was also investigated. As expected, the prepared hydrogels are pH and glucose responsive due to PAA and phenylboronic acid incorporated into the hydrogel, which enables the slow or sustainable release of drug. Moreover, the release processes were fitted with various kinetic models whereas the release was better described by Korsmeyer-Peppas model or the drug release is mainly governed by the release mechanism of the hydrogel is primarily driven by Fickian diffusion from a mechanical point of view. Hydrogel loaded with drug was found to have good antibacterial effects against E. coli and S. aureus, leading to the potential for various medical-related applications.

Antiproliferative activity of syringic acid-loaded nanostructured lipid carriers against MCF-7 human breast carcinoma cells

Syringic acid (SA) is a phenolic herbal compound known to exert antiproliferative properties. However, its poor aqueous solubility and low bioavailability lead to limited therapeutic efficacy in treating breast cancer. Hence, to overcome the above problems, the current study aims to explore the quality by design (QbD) optimized syringic acid loaded nanostructured lipid carriers (SA-NLCs) to treat breast cancer. Here, SA-NLCs were formulated via the hot-melt emulsification method and optimized using the Box-Behnken design. The SA-NLCs exhibited spherical shapes with a particle size and zeta potential of 142.7 ± 4 nm and −14.5 ± 3.6 mV, respectively. The differential scanning calorimetry and powder XRD analyses showed the conversion of crystalline to amorphous form of SA after entrapping into NLCs. Also, the optimized SA-NLCs showed sustained drug release of 75.5 % and 97.6 % in pH 5.5 acetate buffer solution and pH 7.4 phosphate buffer saline respectively. The drug release kinetics study revealed that the optimized SA-NLCs exhibit the Weibull model with the Fickian drug release mechanism. Further, a significantly improved cytotoxicity of the optimized SA-NLCs (IC50: 3.8 ± 0.2 μg/mL) was observed as compared to free SA (IC50: 14.5 ± 1.2 μg/mL) on MCF-7 human breast carcinoma cell lines. Thus, the improved cytotoxicity of SA-NLCs on MCF-7 cell lines can be a suitable strategy for breast cancer treatment.

Polyphenolic tannin-based polyelectrolyte multilayers on poly(vinyl chloride) for biocompatible and antiadhesive coatings with antimicrobial properties

Poly(vinyl chloride) (PVC), a synthetic polymer, is used in various biomedical applications, particularly in the development of catheters. PVC-based catheters are engineered for blood-contacting applications. However, these materials lack antimicrobial properties, resulting in bacterial proliferation and subsequent infections. To overcome this disadvantage, blood-compatible and antimicrobial polyphenolic tannin-based surface coatings, known as polyelectrolyte multilayers (PEMs), were adsorbed onto PVC for the first time. PEMs were created on reduced PVC (Red-PVC) or oxidized PVC (Oxi-PVC) substrates using the layer-by-layer (LbL) approach. An amino-functionalized polyphenolic tannin derivative (TN-NH2), commercially known as Tanfloc, and an unmodified polyphenolic tannin (TN), commercially known as Weibull black, were assembled (15 layers) on Oxi-PVC or Red-PVC at pH 5.0. PVC substrates and PEMs were characterized through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements. The PEMs showed enhanced wettability compared to the unmodified PVC, with water contact angles ranging from 42° to 38°. The root mean square (Rq) roughness of the PEMs ranged from 64.5 nm to 74.1 nm, while the unmodified PVC surface displayed a relatively smooth surface with a roughness of 5.4 nm. Stability tests demonstrated that the PEMs maintained their integrity in phosphate buffer (pH 7.4) over seven days at 37°C. The obtained PEMs were not toxic to human fibroblasts and human erythrocytes. The Live/Dead antimicrobial assay results indicated that the PEMs possessed biocidal activity against Pseudomonas aeruginosa (P. aeruginosa) and antiadhesive capacity toward Staphylococcus aureus (S. aureus) and P. aeruginosa after 24 h of incubation. Cytocompatible and antimicrobial tannin-based PEMs on modified PVC surfaces can represent a significant advancement in mitigating bacterial infections associated with PVC-based catheters.

All-In-One solution for simultaneous phosphonate degradation and orthophosphate recovery by NiFe-Layer double Hydroxide/PDS

Phosphate recovery presents an effective solution to address the conflicting problems of phosphorus pollution and scarcity. However, recovering organic phosphates, such as 1-hydroxyethane 1,1-diphosphonic acid (HEDP), is comparatively complex, which involves multiple processes. Herein, we developed an innovative all-in-one solution to simplify these processes by combining NiFe-layered double hydroxides (NiFe-LDH) and peroxydisulfate (PDS). This combination achieved approximately 90 % conversion of HEDP to orthophosphate, with 100 % of the resulting orthophosphate recovered in 120 min. The exceptional performance in simultaneous HEDP degradation and recovery can be attributed to dual roles of Ni and Fe in NiFe-LDH/PDS. The polyvalent Ni functions as an electron shutter (Ni2+ ⇋ Ni3+ ⇋ Ni2+) in the redox cycles between PDS and HEDP, accounting for effective HEDP degradation. The high complexation stability between Fe(Ⅲ) and orthophosphate (log K = 9.92) allows Fe(Ⅲ) to serve as binding sites for orthophosphate recovery. Moreover, NiFe-LDH/PDS effectively treats HEDP across wide pH ranges (3–––10), which can be ascribed to pH buffers originating from protonation/deprotonation in NiFe-LDH layers. The recovered phosphorus with NiFe-LDH exhibited a slow-release property under soil water solution without notable Ni release, which highlighted its potential usage as a slow-release fertilizer. These features—catalytic and binding sites, and high compatibility—allow NiFe-LDH to achieve concurrent degradation and recovery of organic phosphate in a single solution.

Indicator Films Containing Dendrobium Orchid Flower Extract and TiO2 Nanoparticles for Monitoring Fish Fillet Spoilage

This work aimed to study a novel pH indicator film prepared from carboxymethyl cellulose (CMC)/tapioca starch (TS) incorporating Dendrobium orchid flowers and TiO2 nanoparticles for monitoring fish fillet freshness. The films were prepared based on carboxymethyl cellulose (CMC) and tapioca starch (TS) blend (CMC/TS) incorporated with TiO2 nanoparticles and Dendrobium orchid flower (DOF) extract. The result showed that the DOF extract contained peonidin-3,5-O-diglucoside and exhibited distinguishable color changes in different pH buffers. Likewise, the CMC/TS+TiO2+DOF film’s color changed corresponding to the extract. The X-ray diffraction analysis revealed the expansion of the film’s amorphous region, due to the intermolecular interactions. Analyzing scanning electron microscope images showed the effects of TiO2 and DOF extract on the surface morphology of films. The incorporation of TiO2 and DOF extract into the film formulation improved various film properties, such as redness, opacity, tensile strength, and water solubility. For the sensitivity testing, the color of the CMC/TS+TiO2+DOF film responded to ammonia vapor more than acetic acid vapor, suitable for monitoring seafood spoilage behavior. In addition, the application of film for monitoring the freshness of fish fillets was conducted. The CMC/TS+TiO2+DOF film color changed from purple to bluish-purple corresponding to the spoilage of samples. Indicating its potential as an indicator for monitoring fish fillets' freshness.

Effects of empagliflozin on gonadal functions of hyperglycemic male wistar rats.

Empagliflozin (EMPA) showed antiapoptotic, oxidative and anti-inflammatory potential effect. EMPA attenuates the inflammation and oxidative stress biomarkers in patients with heart failure while significantly decreases the malondialdehyde (a lipid peroxidation marker) levels in the plasma of diabetic patients. The present study examined the effects of moderate hyperglycemia on reproductive function. Sixty male Wister rats ‎ were divided and randomly allocated into four groups of 15 animals each‎‎. Diabetes was induced by a single intraperitoneal injection of a prepared solution containing STZ diluted in 0.1 M sodium citrate buffer (pH 4.5) at a dosage of 40 mg/kg body weight in selected in groups II and III for seven days before starting the treatment with EMPA. The current study revealed that EMPA for eight weeks prevented testicular high glucose-induced oxidative stress markers such as penile nitric oxide (NO), glutathione peroxidase (GPX) and total anti-oxidant capacity (TAC) in STZ-induced hyperglycemia in a rat model. In addition, EMPA ameliorated the high levels of endogenous Interleukin-6 (IL-6) present in gonads in response to an acute inflammatory found in the hyperglycemic STZ-induced rats. The present study further suggested the protective effects of EMPA and how it has a beneficial role and can effectively attenuate hyperglycemia-induced testicular oxidative damage and inflammatory markers as well as androgen dependent testicular enzymes activity as a protective role against the consequences of hyperglycemia and male sub-infertility.

An economic, accessible and stable sulphated cyclodextrin polymer as selector for efficiently separating chiral drugs in HPLC

In this study, sulfopropyl ether β-cyclodextrin polymer (SPE-β-CDP) with simple synthesis steps using cheap reagents was large-scalely prepared. Characterization results showed the average sulfonic group substitution in each β-CD molecule was about 7.261, and there were 195.87 μmol/g β-CD units in polymer. It was low viscosity and produced a little effect on column pressure. It was used as chiral selectors first time to add into mobile phase to separate 13 chiral drugs in HPLC. After investigation, results showed buffer pH, chiral additive concentration, organic phase proportion in mobile phase and flow rate could affect chiral separation. High separation ability of SPE-β-CDP was proved through baseline separation of 12 drugs which attributed to the homogeneity of SPE-β-CDP in sulfonic acid group substitution degree and position. The resolutions of salbutamol, bisoprolol, chlorpheniramine, propranolol and metoprolol could be even up to 7.47–19.02, which were significantly better than that of some references. Separations of 4 chiral drugs were even better than that of CE. Compared with monomer, SPE-β-CDP showed better chiral separation ability. SPE-β-CDP could be used in both of C8 and C18 columns. It was stable in batches and showed good recyclability and reusability. These provided a new strategy for chiral separation.

Formation of left-handed helices by C2'-fluorinated nucleic acids under physiological salt conditions.

Recent findings in cell biology have rekindled interest in Z-DNA, the left-handed helical form of DNA. We report here that two minimally modified nucleosides, 2'F-araC and 2'F-riboG, induce the formation of the Z-form under low ionic strength. We show that oligomers entirely made of these two nucleosides exclusively produce left-handed duplexes that bind to the Zα domain of ADAR1. The effect of the two nucleotides is so dramatic that Z-form duplexes are the only species observed in 10 mM sodium phosphate buffer and neutral pH, and no B-form is observed at any temperature. Hence, in contrast to other studies reporting formation of Z/B-form equilibria by a preference for purine glycosidic angles in syn, our NMR and computational work revealed that sequential 2'F…H2N and intramolecular 3'H…N3' interactions stabilize the left-handed helix. The equilibriumbetween B- and Z- forms is slow in the 19F NMR time scale (≥ms), and each conformation exhibited unprecedented chemical shift differences in the 19F signals. This observation led to a reliable estimation of the relative population of B and Z species and enabled us to monitor B-Z transitions under different conditions. The unique features of 2'F-modified DNA should thus be a valuable addition to existing techniques for specific detection of new Z-binding proteins and ligands.

Simple and Fast Determination of Carbaryl Pesticide in Commercial Topical Formulations by Capillary Electrophoresis

A novel analytical method using capillary zone electrophoresis (CZE) for simple and fast determination of the pesticide carbaryl in commercial topical formulations was developed and validated. The carbaryl was previously hydrolyzed quantitatively under an alkaline medium (NaOH solution) to form 1-naphthol, which was separated and quantified by CZE with spectrophotometric detection at 214 nm. Optimization of the hydrolysis reaction regarding time and NaOH concentration was conducted. The CZE separation was achieved in less than 3 min using a bare silica capillary (60 cm total length) and a 10 mmol L-1 sodium borate buffer (pH 9.3) as background electrolyte. The proposed CZE method was linear in the 0.25 to 70 mg L-1 concentration range, as attested by a coefficient of determination (R2) higher than 0.999 and confirmed by the lack of fit test. Recovery tests at three concentration levels provided recovery percentages ranging from 80 to 115%, indicating acceptable accuracy. The limits of detection (LOD) and quantification (LOQ) were 0.08 and 0.25 mg L-1, respectively. The proposed CZE method was successfully applied for carbaryl determination in commercial samples of topical formulations such as powders and dry bath gel.

Evaluation of strain variability of food microorganisms in response to decontamination by pulsed electric fields and thermal treatments

The effect of pulsed electric fields (PEF) and thermal treatments on the inactivation of the population of 40 strains of 4 model microorganisms (Escherichia coli, Listeria monocytogenes, Lactiplantibacillus plantarum, Saccharomyces cerevisiae) were investigated. Microbial samples of McIlvaine buffer pH 7.0 were subjected to pulses with electric field strength 20 kV/cm and total specific energies (88, 136, and 184 kJ/kg). Depending on the species and strain, microorganisms exhibited various resistances. PEF microbial resistance and strain variability data were correlated to the total specific energy used. E. coli strains showed statistical log10 inactivation differences under the 88 and 136 kJ/kg but not under the 184 kJ/kg PEF treatment. In contrast, L. monocytogenes strains showed statistical log10 inactivation differences only under the 184 kJ/kg treatment. L. monocytogenes L6 strain was identified as the most resistant strain at PEF treatment (184 kJ/kg). This result was in accordance with the resistance under thermal treatment (62.8 °C, 30 min). Industrial relevanceThe identification of target microorganisms related to their resistance in one or more technologies can help at establishing treatment conditions that reassure food safety. Data obtained in this research show that species and strain behaviours vary and are dependent on the technology and the applied treatment conditions. Thus, the resistance exhibited by microorganisms of public health importance may be dependent on the used technology and the applied treatment.