Acid Buffer Research Articles

Preparation and characterization of andrographolide nano-cocrystals using hummer acoustic resonance technology.

Andrographolide (AG) is a diterpene lactone with significant anti-inflammatory and antitumor activities. However, the poor water solubility limits its clinical application. An andrographolide-salicylic acid (AG-SLA) nano-cocrystal delivery system was rapidly developed using hummer acoustic resonance (HAR) technology in this research. The formulation of the AG-SLA nano-cocrystal suspension and the process parameters for HAR technology were optimized in a high-throughput manner, with SDS-Tween 80 as the optimal composite stabilizer. Nano-cocrystal suspension of AG-SLA with an average particle size of 190 nm were successfully prepared, and then the optimal formulation were tenfold scaled up. Freeze-drying was adopted to solidify the nano-cocrystal and improve its stability. Various analytical techniques were used to characterize the particle size and solid state of the nano-cocrystals. The high-energy input from the HAR instrument induced partial amorphization of the nano-cocrystals, as confirmed by PXRD and DSC analyses. Saturation solubility experiments demonstrated that the solubility in pH 1.2 hydrochloric acid buffer and pH 6.8 phosphate buffer increased by 5.74 times and 6.82 times, respectively, compared to raw AG. In vitro dissolution tests indicated that the cumulative release over 120min in pH 1.2 hydrochloric acid buffer and pH 6.8 phosphate buffer increased by 1.60 times and 1.88 times, respectively, compared to raw AG.

The Pharmaceutical Composition of Rocuronium Bromide May Promote Catecholamine Release From PC-12 Cells.

Several cases of pheochromocytoma presenting with hypertensive crises after anesthesia induction, possibly caused by rocuronium injection, have been reported. Rocuronium has two compositions: rocuronium bromide (RB) in sodium acetate hydrate/acetic acid buffer solution (acetic acid vehicle)and RB in glycine/hydrochloric acid buffer solution (hydrochloric acid vehicle). This study assessed the effect of rocuronium composition on the release of catecholamine from PC-12 rat adrenal pheochromocytoma cells. PC-12 cells (3x105 cells) were cultured for 96 hours, then 1 mL of reagent was added for five minutes. First, the experiment used phosphate-buffered saline (PBS (-)), RB in PBS (-), an acetic acid vehicle, and RB in the acetic acid-based vehicle. Next, the experiment used an acetic acid vehicle and a hydrochloric acid vehicle. Then the experiment used an acetic acid vehicle and a mixed solution of 0.2 mL acetic acid vehicle + 0.8 mL normal saline (NS). Cell supernatants were collected and norepinephrine (NE) and dopamine (DA) concentrations were measured using high-performance liquid chromatography. Release of NE and DA was caused by acetic acid vehicle, not by RB in PBS (-). Hydrochloric acid vehicles similarly showed a significantly lower release of NE and DA than acetic vehicle acid (NE, P=0.002; DA, P=0.002). In addition, the acetic acid vehicle diluted 5-fold with NS showed a significantly lower release of NE and DA than the acetic acid vehicle alone (NE, P=0.005; DA, P=0.002). The concentration of acetic acid in the buffer solution, not RB, caused the release of catecholamines from PC-12 cells.

3D printed extended-release hydrochlorothiazide tablets.

In this study 3D printed tablets (printlets) with extended release of hydrochlorothiazide (HHT) as model active ingredient were designed and developed. Four formulations, F0.1SSE, F1SSE, F0.1DLP and F1DLP, have been manufactured and characterized, using non-typical semi-solid extrusion (SSE) with UV light solidification and digital light processing (DLP) techniques. Obtained rheological studies pointed out to F1SSE and F1DLP as more suitable for SSE and DLP printing, respectively. Photopolymerization process between photopolymer (PEGDA) and photoinitiator (DPPO; 0.1% and 1%) was investigated using FTIR, with PCA modeling utilized to analyze spectral variations over time and estimate crosslinking kinetics. SSE printlets averaged ∼6.5 mm in diameter, ∼3 mm in height and ∼110 mg in mass, while DLP printlets averaged ∼8.5 mm in diameter, ∼2.5 mm in height, with masses of ∼170 mg (F0.1DLP) and ∼220 mg (F1DLP). All four formulations complied to the requirements of European pharmacopeia for uniformity of dosage units of single dose preparations. In vitro release studies indicated extended-release profiles in both 0.1M Hydrochloric acid (HCl) and phosphate buffer pH 6.8 for SSE and DLP printlets. The release kinetics of HHT from the printlets were modeled to fit First order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell equations and the most probable ones were determined based on the R2 values and Akaike information criterion. FTIR and Raman spectroscopic analyses of printlets confirmed the presence of characteristic peaks from both, HHT and excipients, as well as modifications in bonds due to the photopolymeric reaction.

Assessment of polyvinylpyrrolidone vinyl acetate effect on quercetin properties in binary solid dispersion prepared by hot melt extrussion

Introduction. Flavonoids, despite their pronounced therapeutic benefits, are limitedly used in medicine as active pharmaceutical ingredients (API) owing to a complex of unsatisfactory physicochemical properties. In order to study the mentioned problem, we decided to use quercetin as model compound with extremely low water solubility and dissolution in gastrointestinal (GI) tract media. Therefore, the main idea appears to study the possibility and prospects of hot melt extrusion (HME) application for enhancement the solubility properties of quercetin in the composition of solid dispersion system (SDS) based on hydrophilic polymeric carrier (polyvinylpyrrolidone vinyl acetate, PVP/VA). Consequently, there is a necessity to select effective drug-to-polymer ratio in solid dispersion for providing better solubility and dissolution properties.Aim. Assessment of PVP/VA effect on quercetin solubility properties in binary solid dispersion prepared by HME.Materials and methods. Quercetin substance with purity 98 % was purchased from Molekula Limited, United Kingdom. PVP/VA (copolymer of polyvinylpyrrolidone with vinyl acetate in the ratio of 60 : 40, VIVAPHARM® PVP/VA 64) as carrier was procured from JRS PHARMA (JRS PHARMA GmbH & Co. KG, Germany). Quercetin SDS were prepared using micro-conical twin screw compounder HAAKE™ MiniCTW (Thermo Fisher Scientific, Germany). The obtained samples were analyzed by phase-contrast microscopy, FTIR spectroscopy and differential scanning calorimetry (DSC). Quercetin quantitative content in SDS were determined by UV-spectrophotometry.Results and discussion. The improvement of water solubility and dissolution rates of quercetin SDS in comparison with pure substance was observed for all solid dispersion compositions irrespective to drug-to-polymer ratio. Notably, with reduction of quercetin content in SDS compositions the PVP/VA contribution was increased. We found partial or even complete amorphization of API in formulations with 1 % and 5 % quercetin content, resulting in the improvement of water solubility properties, stability of solutions and increased dissolution rates in GI tract media. Water solubility of 1 % SDS relative to pure substance was enhanced by 353-fold. At the same time, the complete release of quercetin from 1 % SDS was achieved in 40 minutes in the hydrochloric acid and citrate buffer, and also quercetin dissolution of 90 % in 60 minute was observed in phosphate buffer.Conclusion. 1 % quercetin SDS based on PVP/VA appears to be the most promising for solid dosage forms development.

Intensive monocropping of bananas decreases the soil acid buffering capacity via ammonia-oxidizing bacteria

Ammonia-oxidizing microorganisms (AOM) are vital for soil nitrogen cycling, nutrient availability, and soil health during sustainable agriculture. Long-term continuous cultivation of bananas and improper chemical fertilization affect the adaptability of AOM; however, the underlying basis for this phenomenon is unclear. This study utilized 16S rRNA gene and metagenomic sequencing techniques to examine soil from banana plantations that were continuously cultivated for 2, 3, 7, 10, 12, and 13 years (Y2, Y3, Y7, Y10, Y12, and Y13, respectively). The results indicated a significant decrease in soil acidity buffering capacity (pHBC) with increasing years of continuous cropping. Furthermore, compared with forest soil (Y0), Y7, Y10, Y12, and Y13 soils exhibited a significantly increased potential nitrification rate (PNR) as well as an abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), with no significant difference in complete ammonia oxidizers (comammox). Principal component analysis (PCA) further demonstrated marked differences in chemical properties and ammonia-oxidizing microbial community structures between the soils under long-term (Y7, Y10, Y12, Y13) and short-term (Y2, Y3) banana cultivation. In addition, metagenome analysis results indicated that the relative abundance of Nitrososphaera-AOA and Ca. Nitrosocosmicus-AOA as well as Nitrosospira-AOB, Nitrosovibrio-AOB, Nitrosomonas-AOB, and comammox Nitrospira jacus was significantly higher in Y7 and Y13 soils than in Y0 controls. Redundancy analysis (RDA) identified pHBC, CEC, and NH4+ as the primary chemical factor responsible for the differences in AOM microbial communities, whereas random forest analysis revealed that Nitrosospira-AOB significantly contributed to PNR. In summary, long-term continuous banana cultivation primarily stimulates AOB promote soil ammonia oxidation, leading to soil acidification.Graphical

Evaluation of Quercetin's Bioenhancing Effect on Oral Pharmacokinetics of Rosuvastatin in Wistar Rats Using RP-HPLC Method.

The absolute oral bioavailability of rosuvastatin (RST), a secondgeneration statin, is low i.e. 20% and only 10% is recovered as metabolite N-desmethy l rosuvistatin. Since it is a hydrophilic statin, RST relies on the organic anion transporting polypeptide- 1B1 (OATP-1B1), as the key mechanism for active transport into hepatocytes. Quercetin (QUE) being a bio enhancer and inhibitor of OATP1B1 can augment the bioavailability and pharmacokinetics of RST. The present study includes the development of a simple and validated bioanalytical Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method for the estimation of RST and to study the effect of co-administration of QUE as a bio enhancer on its bioavailability. An analytical column of Kromasil 100, C18 (250 mm × 4.6 mm, 5 μm), was used for chromatographic separationand acetonitrile (ACN): acetic acid buffer pH 3.0 adjusted with glacial acetic acid (55:45 Vol. %) as mobile phase with flow rate 1.0 ml/min monitored at 242 nm. The ACN: methanol (50:50 Vol. %) was employed as the final solvent for extraction. The developed method has been successfully applied in a study on the pharmacokinetics of the drug RST in rats after co-administration of QUE, which was carried out using non-compartmental analysis in order to estimate the blood concentration of the drug. The pharmacokinetics of RST was found to be altered significantly (highest concentration of RST in the blood (Cmax) = 67.3 ng/ml to 122.2 ng/ml) (p < 0.001), area under curve (AUC)0-t (p < 0.0001) and AUC0-inf (p = 0.0005) when co-administered with QUE at 120 min (tmax). The results are in accordance with the fact that QUE increases plasma levels in rats through herb-drug interactions.

Sensitive electrochemical detection of glycated hemoglobin (HbA1c) using cobalt metal-organic framework/two-dimensional molybdenum diselenide nanocomposite-based immunosensors amplified by polyoxometalate/DNA aptamer.

Clinical diagnosis and long-term diabetes management are advanced by monitoring glycated hemoglobin A1c (HbA1c) levels. New sensitive sandwich-like immunosensors for the diagnosis of early diabetes toward detecting HbA1c and hemoglobin (Hb) are demonstrated for the first time. DNA aptamers are used for signal amplification in the sensors for the detection of HbA1c and Hb. The immunosensors are constructed by coating with a cobalt-based metal-organic framework (Co-MOF)/two-dimensional molybdenum diselenide (2D MoSe2) composite onto a working electrode of an ItalSens screen-printed electrode (SPE) inserted into a Sensit/Smart Potentiostat affixed to a smartphone. After the immobilization of the antibodies, the detection is obtained by incubating the resultant SPEs in target solutions and then detecting the response of Keggin-type polyoxometalate (POM) bound on the DNA aptamer chains. In the selected potential window, the POM (silicotungstic acid, H4[α-SiW12O40]) used in this study exhibits the electron-transfer processes I and II ([α-SiW12O40]4-/5- and [α-SiW12O40]5-/6-, respectively) in the acidic buffer electrolyte. Our proposed device demonstrates exceptional performance in the recovery test of %HbA1c in healthy human plasma samples. The sensitivity, selectivity, and stability of this immunosensor are exceedingly outstanding, which makes it one of the potential analytical devices for diagnosing early diabetes by a %HbA1c assay.

Beta-Alanine Supplementation for CrossFit® Performance

This study aimed to investigate whether beta-alanine supplementation (BA) improves performance and rating of perceived exertion (RPE) and reduces the respiratory exchange ratio (RER) during a CrossFit® workout. Fourteen participants were randomized in a double-blind design to either BA or placebo, with 12 participants (7 males, 5 females, 32 ± 9.2 y) completing the study. Participants performed two tests, separated by three weeks of supplementing with either 6.4 g/day of BA or placebo. Performance tests involved time to complete an adapted CrossFit® “Fran” Workout of the Day: 21-15-9 repetition scheme alternating between dumbbell thrusters and kipping pull-ups. No significant differences between the BA group and the placebo group were observed for performance time improvement (−13.4 s vs. −12.9 s, p = 0.97), change in mean RER (0.06 vs. 0.05, p = 0.84), or change in RPE (10-point scale) (−0.4 vs. −0.07, p = 0.56). There was a group × time × time during test interaction for RER (p = 0.021). Compared to pre-testing, post-testing RER was higher at the 25% time point of the test for the BA group and at the 75% and 100% time points in the placebo group (p &lt; 0.05). Beta-alanine did not show significant ergogenic effects during an adapted version of the CrossFit® workout “Fran”, although it might have helped with the buffering of acidity later in the test, based on RER.

The High-Resolution Structure of a Variable Lymphocyte Receptor From Petromyzon marinus Capable of Binding tothe Brain Extracellular Matrix.

Variable lymphocyte receptors (VLRs) are antigen receptors derived from the adaptive immune system of jawless vertebrates such as lamprey (Petromyzon marinus). First discovered in 2004, VLRs have been the subject of numerous biochemical and structural investigations. Due to their unique antigen binding properties, VLRs have been leveraged as possible drug delivery agents. One such VLR, previously identified and referred to as P1C10, was shown to bind to the brain extracellular matrix. Here, we present the high-resolution X-ray crystal structure of this VLR determined to 1.3 Å resolution. The fold is dominated by a six-stranded mixed β-sheet which provides a concave surface for possible antigen binding. Electron density corresponding to a 4-(2-hydroxyethyl)piperazine-1-propanesulfonic acid buffer molecule (HEPPS) was found in this region. By comparing the P1C10 molecular architecture and its buffer binding residues with those of other VLRs previously reported, it was possible to illustrate how this unique class of proteins can accommodate diverse binding partners. Additionally, we provide an analysis of the experimentally determined structure compared to the models generated by the commonly used AlphaFold and iTASSER structure prediction software packages.

A Pre-Column Derivatization Method for the HPLC-FLD Determination of Dimethyl and Diethyl Amine in Pharmaceuticals.

In recent years, the detection of nitrosamine precursors has become an important issue for regulatory authorities such as the European Medicines Agency (EMA) and the Food and Drug Administration (FDA). The present study provides a pre-column derivatization method for the analysis of dimethylamine (DMA) and diethylamine (DEA) in pharmaceutical products using HPLC and a fluorescence detector. Appropriate chromatographic parameters, including mobile phase composition (organic solvent, buffer, pH), elution type, flow rate, temperature, and λexcitation/emission, were investigated. Analysis was performed at λexcitation = 450 nm and λemission = 540 nm on a C18 column (at 40 °C) using gradient elution as a mobile phase with Eluent A: Phosphoric Acid Buffer (20 mM, pH = 2.8) and Eluent B: methanol, with a flow of 0.8 mL/min. The method was validated according to ICH specifications in terms of linearity (0.5-10 ng/mL for DMA and 5-100 ng/mL for DEA), specificity, and robustness, as well as repeatability, intermediate precision (%RSD < 2.9), and accuracy (% recovery 98.2-102.0%). The derivatization process was optimized using the "Crossed D-Optimal" experimental design procedure, where one mixture component was cross-correlated with two factors. The stability of the samples was studied over a period of one month. To process the samples (pharmaceuticals), various purification techniques were tried using solid/liquid or liquid/liquid extraction with dichloromethane. Finally, a straightforward solid-phase extraction (SPE, C18) method was chosen prior to derivatization. The method was successfully applied, since the extraction recoveries were >81.6% for DMA (0.5 ppm) and >81.1% for DEA (5 ppm). Based on the results obtained and the available literature, the scientific community seeks, by proposing flexible analytical methods, to delimit the problem of nitrosamines.

Effects of buffers on spray-freeze-dried/lyophilized high concentration protein formulations

Solid-state protein formulations are known to exhibit enhanced storage stability compared to their liquid dosage form counterparts. pH is one of the factors affecting the stability of protein formulations. The pH of protein formulations in the solution could be influenced by the buffer used, directly impacting their solid-state stability. During lyophilization, buffer components may interact with other formulation components present in the protein formulations, causing a pH shift. This study aimed to investigate the effects of phosphate buffer and amino acid buffers (such as histidine and/or arginine) on the physical properties and accelerated storage stability of spray freeze-dried or lyophilized protein formulations. A model protein, bovine serum albumin (BSA), was used to prepare high-concentration protein formulations. The formulations consisted of BSA, trehalose, and mannitol in an 80:15:5 ratio (w/w), respectively. Various buffers were utilized in the preparation of protein formulations, and the resultant solid formulations underwent screening via accelerated stability study using size exclusion chromatography (SEC). The combination of phosphate and arginine buffers resulted in increased monomer loss in the accelerated storage stability study. Additional characterizations, including solid-state Fourier transform infrared spectroscopy (ssFTIR) and powder X-ray diffraction (PXRD), were conducted. While these analyses did not definitively elucidate the mechanism behind the observed instability, their outcomes provide valuable insights for further investigation, highlighting the need for future research in this area.

Paintable, Fast Gelation, Highly Adhesive Hydrogels for High-fidelity Electrophysiological Monitoring Wirelessly.

High-fidelity wireless electrophysiological monitoring is essential for ambulatory healthcare applications. Soft solid-like hydrogels have received significant attention as epidermal electrodes because of their tissue-like mechanical properties and high biocompatibility. However, it is challenging to develop a hydrogel electrode that provides robust contact and high adhesiveness with glabrous skin and hairy scalp for high-fidelity, continuous electrophysiological signal detection. Here, a paintable, fast gelation, highly adhesive, and conductive hydrogel is engineered for high-fidelity wireless electrophysiological monitoring. The hydrogel, consisting of gelatin, gallic acid, sodium citrate, lithium chloride, glycerol, and Tris-HCl buffer solution exhibits a reversible thermal phase transition capability, which endows it with the attributes of on-skin applicability and fast in situ gelation with 15 s, thereby addressing the aforementioned limitations. The introduction of gallic acid enhances the adhesive properties of the hydrogel, facilitating secure electrode attachment to the skin or hairy scalp. To accentuate the potential applications in at-home electrophysiological health monitoring, the hydrogel electrodes are demonstrated for high-fidelity electrocardiogram recording for one hour during various daily activities, as well as in simultaneous electroencephalogram and electrocardiogram recording during a 30 min nap.

PH Determination of Acetic Acid-Sodium Acetate Buffer: An Application of Henderson-Hasselbalch Equation at Room Temperature

In article, we have reported the applying of Henderson-Hasselbalch equation in determination of pH of acetic acid and sodium acetate buffer solutions at about 298 Kelvin as room temperature. In preparation of these buffer solutions, we have taken 1.5 ml of glacial acetic acid into 100 ml of standard flask for making up 0.2M of acetic acid solution, and 0.64 gm of sodium acetate were dissolved into 100 ml distilled water. Now, we taken 36.2 ml prepared solution of sodium acetate into 100 ml of standard flask and added 14.8 ml of prepared acetic acid to make its volume 100 ml by using of distilled water, it is a buffer. In measuring of pH of prepared buffer solutions, we have been using a calibrated digital pen pH meter for accurate and quick reading. In observation, the pH of buffer solutions a quite fluctuation was appeared. But, it has gradually raised by adding small amount of basic 5N NaOH solution into buffer sample, and, an adjusted pH was being to 4.7 as well.

Bioactive Self-Polymerizing Resin with Surface Pre-Reacted Glass Ionomer Fillers for Suppressed Enamel Demineralization.

The treatment of damaged enamel surfaces involves modification of the enamel surface with artificial materials or the development of a pseudo-enamel, with research focusing on bioactive and biomimetic materials. In this study, a bioactive auto-polymerizing resin (APR) was developed by adding surface-pre-reacted glass ionomer (S-PRG) fillers of different quantities to APR. Its bioactive effects were evaluated via pH neutralization, ion release, and inhibition of enamel demineralization studies. The pH and fluoride ion release were measured using ion-specific electrodes, revealing that the APR disk with the S-PRG filler immediately neutralized the lactic acid solution (pH 4.0) through ion release. Inductively coupled plasma atomic emission spectrometry revealed that the Sr ion release peaked on the first day, with the other ions following the order F > B > Si > Al > Na, exhibiting a weekly decrease in the same order. Scanning electron microscopy was used to examine the enamel block morphology of the disks after 7 d of incubation, revealing enamel demineralization in disks without the S-PRG filler, whereas no demineralization occurred in disks with the S-PRG filler. APR containing the S-PRG filler demonstrated acid buffering suppressed enamel demineralization and bioactive properties.

Modified mesoporous silica nanocarriers containing superparamagnetic iron oxide nanoparticle, 5-fluorouracil or oxaliplatin, and metformin as a radiosensitizer, significantly impact colorectal cancer radiation therapy

This study investigates the anticancer effects of SPION-based silica nanoparticles carrying 5-fluorouracil (5-FU) or oxaliplatin (OX), and metformin (MET) on colorectal cancer cells. Nanocarriers were equipped with pH-responsive gold gatekeepers for controlled release, PEGylation for longer circulation, and folic acid (FA) for targeted delivery. The effects were evaluated by investigating cell viability, cellular uptake, flow cytometry, and clonogenic assay in vitro. The efficacy of the system was also tested in vivo on C57BL/6 mice bearing HT-29 tumors, and potential side effects were evaluated.Nanocarriers were synthesized with hydrodynamic diameters of 79.8 nm for 5-FU and 85.2 nm for OX; zeta potentials of −21 and –22 mV, respectively, and remained stable after 72 h. Encapsulation efficiencies were 85 % for 5-FU, 80 % for OX, and 83 % for MET, with loading capacities of 44 %, 38 %, and 41 %, respectively. Drug release in acidic buffer was 38.7 % for 5-FU, 32.8 % for OX, and 43.5 % for MET. MTT assay showed increased toxicity due to FA conjugation, while PEGylation reduced the hemolysis activity. Targeted nanocarriers demonstrated superior cellular uptake and tumor localization compared to non-targeted variants. The combination of 5-FU-MET and OX-MET nanocarriers with radiation therapy (RT) demonstrated the greatest effect on their antitumor activity, accompanied by minimal side effects indicating effective tumor targeting in vivo. MRI and CT imaging further supported these findings. This study underscores the synergistic impact of MET alongside RT on the inhibition of cancer cells and tumor growth for both targeted 5-FU and OX nanocarriers reflecting the significant radiosensitizing properties of MET.

Examination of the impact of using lactose or permeate for protein standardisation of skimmed milk on viscosity characteristics during evaporation

The effect of permeate and lactose for protein standardisation of skim milk concentrate, was investigated during evaporation. Analysis of the viscosity–total solids (TS) profiles of each treatment demonstrated that the unstandardised protein sample had the greatest increase in viscosity, followed by permeate and finally lactose‐standardised samples. Heat stability and acid buffering capacity of the permeate standardised skim milk samples were higher when compared to the lactose‐standardised samples. This work identifies how standardisation media can impact the viscosity of concentrated skim milk, enabling higher TS at the evaporator outlet in some circumstances which could have the potential to improve overall process efficiency. Furthermore this work demonstrates that, evaporating to a target viscosity rather than target TS would offer greater control and consistency during processing.

Applicability of QbD-assisted Analytical Method for Simultaneous Detection of Tetrahydrocurcumin and Folic Acid in Developed Nanostructured Lipid Carriers

Aims: Applicability of QbD-assisted analytical method for simultaneous detection of tetrahydrocurcumin and folic acid in developed nanostructured. Background: Diabetic foot ulcer (DFU) is a multifactorial disorder that involves chronic inflammation, oxidative stress and neuropathy. Current treatment therapies involving the use of growth factors and skin substitutes being costly, are out of reach for the majority of patients. The present research explored the usefulness of (5929IN008, application number 202211045937), a combination of tetrahydrocurcumin and folic acid-loaded nanostructured lipidic carriers. Objectives: To develop and validate a QbD-assisted method for simultaneous analysis of tetrahydrocurcumin (THC) and folic acid (FA). Applicability of the above method to determine total drug content (TDC) and entrapment efficiency (EE) of nanostructured lipid carriers (NLCs) loaded THC and FA. Methods: A high-performance liquid chromatographic (HPLC) method was developed, optimized and validated using Box-Behnken design for improved method performance. Chromatographic separation was conducted on a Supelco 250 x 4.6 mm (5 μm) column with optimized mobile phase composition containing tetrahydrofuran: citric acid buffer pH 3.5 (50:50) at a flow rate of 0.4 mL.min-1 and diode array detection between 210 and 360 nm. Results: The method developed in a concentration range of 1 to 100 μg.mL-1 was found to be linear (R2 0.999, p≤0.001), accurate (99.10-101.70%) and precise with high recovery values in intra and inter-day results. The system adaptability and robustness evaluation revealed that the percent recovery ranged from 96.90 to 102.80%, and the percent relative standard deviation (%RSD) values were less than 2%. Moreover, the method was further applied for the determination of TDC (86±6% and 96±8%) and drug EE (81±21% and 73±13%) for THC and FA, respectively. Conclusion: The investigation indicated the applicability of the developed and validated method for the estimation of THC and FA in the developed nanostructured lipidic carriers.

Modified streptozotocin-induced diabetic model in rodents.

Streptozotocin (STZ)-induced type I diabetes mellitus (DM) models have been pivotal in diabetes research due to their ability to mimic the insulin-dependent hyperglycemia akin to human type I diabetes. However, these models often suffer from poor induction rates and low survival post-STZ induction, especially in long-term experiments, necessitating insulin supplementation, which introduces additional variables to experiments. To address this, we present a novel modification to the STZ-induced DM model in C57BL/6J mice to improve survival rates without insulin supplementation. Our method involves non-fasting, low-dose STZ injections dissolved in pH-neutral phosphate buffer saline instead of acidic sodium citrate buffer, administered over 5 days. We observed hyperglycemia induction in 94.28% of mice within a week post-injection, with stable high blood glucose levels, stable body weight, and minimal mortality up to 21 weeks. Notably, omitting 10% sucrose in water and fasting did not affect hyperglycemia induction. Our findings suggest that the modified protocol not only decreases the experimental effort of the researchers, but reduces animal stress and mortality, thus enhancing experimental outcomes and animal welfare. By optimizing the STZ-induced DM model in C57BL/6J mice, our study provides a valuable resource for researchers aiming to study diabetes and its complications while minimizing experimental variability and animal usage.

A combination of carbonates and Opuntia ficus-indica extract protects esophageal cells against simulated acidic and non-acidic reflux in vitro

Buffering of stomach acid by antacids is a well-established symptomatic therapy for heartburn. In addition, preparations from prickly pear (Opuntia ficus-indica) have been shown to reduce tissue damage in experimental gastritis models and to attenuate gastrointestinal discomfort in patients. Both active principles have been included in a fixed-combination product for symptomatic treatment of heartburn containing carbonate antacids (CaCO3 and MgCO3) and an extract from Opuntia ficus-indica cladodes. The aim of the study was to characterize the acid neutralization and esophageal cell protective activities of the product and its individual active ingredients in a set of in vitro assays. Acid neutralization was assessed in a simulated stomach model. Protective activity of individual constituents and in combination was analyzed in an esophageal cell line (COLO-680 N) exposed to low pH and deoxycholic acid to simulate acidic and non-acidic reflux challenge. The combination product protected cells against low pH mediated cytotoxicity via acid neutralization by carbonates. Opuntia extract itself and the combination product attenuated bile acid-induced cell irritation as measured by reduced release of proinflammatory interleukin-6 and -8. In conclusion, addition of Opuntia extract to a mineral antacid provides dual protection against acidic and non-acidic simulated reflux challenge.

Chemoselective oxidative N-debenzylation of aryl halogenated amines using the Laccase LAC97/TEMPO system

The N-debenzylation of aryl-halogenated amines using the Laccase LAC97/TEMPO system is reported, demonstrating selective N-debenzylation with no dehalogenation of the phenyl ring, which is observed with conventional debenzylation methods such as palladium-catalysed hydrogenation. This reaction was performed under ambient conditions in acidic buffer with 5 % DMSO as co-solvent in an open-to-air vessel. The versatility and robustness of the system was demonstrated on substrates harbouring different halogen moieties. The limitations of the Laccase LAC97/TEMPO system were also studied, highlighting the formation of by-products due to overoxidation on selected substrates. A series of substrates with various halogens were studied. High conversion (78–90 %) in 6 h and full conversion was achieved within 24 h using HPLC to monitor the reaction. Overall, this system is presented as a chemoselective N-debenzylation alternative for aryl-halogenated substrates.