Spectrophotometric Method Research Articles

Validation of UV-Vis spectrophotometric colorimetric methods for Rifampicin quantification in PBS & biological matrices.

Rifampicin (RIF) is the main treatment for tuberculous meningitis (TBM), but its limited penetration across the blood-brain barrier significantly reduces its therapeutic efficacy. To address this limitation, smart-pH nanoparticles were designed to release RIF in inflamed area and incorperated into a thermosensitive in situ gel for enhanced drug delivery via the olfactory nerve. UV-Vis spectrophotometry and colorimetric methods to quantify RIF in various media and biological matrices, including phosphate-buffered saline (PBS) at pH 7.4 and 5.0, plasma, and brain tissue. The main validation parameters assessed were selectivity, specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, extraction recovery, and dilution integrity. Method validation followed International Council for Harmonization (ICH) guidelines, demonstrating excellent linearity (r2 = 0.999) and lower limit detection (LOD) of approximately 0,25-0.49 μg/mL were achieved in all media. The method demonstrated high accuracy (%RE -11.62% to 14.88%) and precision (%RSD 2.06% to 13.29%), meeting regulatory requirements. This validated approach enables reliable RIF quantification in biological samples, supporting its application in in vitro release studies, ex vivo permeability studies, and in vivo pharmacokinetic evaluations. These findings contribute to the advancement of targeted drug delivery systems for TBM treatment.

An Ionic Liquid-Assisted Mixed Micelle-Mediated Centrifuge-Less Cloud Point Extraction Spectrophotometric Method for the Determination of Molybdenum(VI)

A novel method for the spectrophotometric determination of trace amounts of molybdenum has been developed. This method utilizes a centrifuge-less cloud point extraction (CL-CPE) in a mixed micellar (MM) system containing a nonionic surfactant (Triton X-114) and an ionic liquid (Aliquat® 336, A336). The chromophore chelating reagent employed was 4-nitrocatechol (4NC, H2L). This work marks its first application as a CPE reagent. Under the optimal conditions, Mo(VI) forms a yellow ternary complex with 4NC and A336, which can be represented by the formula (A336+)2[MoO2L2]. The method possesses the following characteristics: limit of detection (LOD) of 3.2 ng mL−1, linear range of 10.8–580 ng/mL, absorption maximum of 435 nm, molar absorptivity coefficient of 3.34 × 105 L mol−1 cm−1, and Sandell’s sensitivity of 0.29 ng cm−2. The method has been successfully employed for the determination of molybdenum in reference standard steel samples, bottled mineral water, and a molybdenum-containing dietary supplement.

Eco-Friendly UV/Vis Spectrophotometric Determination of an Anticonvulsant and Cobalamin-Based Supplement in Bulk and Dosage Forms

Abstract A simple, precise, accurate, and economical UV spectrophotometric method was developed for the simultaneous estimation of lacosamide and cobalamin in bulk and tablet dosage forms. The method was validated as per ICH guidelines for parameters including linearity, accuracy, precision, robustness, and sensitivity. Both drugs followed Beer-Lambert’s law in the concentration range of 0.1–0.9 mg/mL for lacosamide and 0.1–0.9 µg/mL for cobalamin, with a correlation coefficient of 0.991. The method showed good sensitivity, with low limits of detection and quantification. The percentage recovery was found to be 99.13–100.2% for lacosamide and 97.46–101.25% for cobalamin, within acceptable limits. Assay results were 100.01% and 100.22% for lacosamide and cobalamin respectively, indicating accuracy. Precision was confirmed by %RSD values below 2%. Robustness was demonstrated by minor changes in NaOH concentration and detection wavelengths. The method showed no interference from excipients and is suitable for routine quality control. Thus, the developed method is a reliable alternative for the simultaneous analysis of lacosamide and cobalamin in combined pharmaceutical formulations. Keywords: Anticonvulsant, Lacosamide, Cobalamin, UV Spectroscopy, Method Validation

Association of Vitamin D Supplementation with Glutathione Peroxidase (GPx) Activity, Interleukine-6 (IL-6) Levels, and Anxiety and Depression Scores in Patients with Post-COVID-19 Condition

Coronavirus disease 2019 (COVID-19) presents with various symptoms, and some patients develop post-COVID-19 condition (PCC). Vitamin D has shown therapeutic potential in COVID-19 and may offer benefits for PCC. The aim of this study was to evaluate the differences associated with two supplementation strategies (bolus and daily) on interleukin-6 (IL-6) levels, glutathione peroxidase (GPx) activity, and clinical outcomes in PCC patients, regardless of whether target 25 (OH) D levels reached the ideal range. We conducted a self-controlled study in which 54 participants with PCC were supplemented with vitamin D3 (n = 28 bolus and n = 26 daily) for 2 months. Blood samples were collected to measure IL-6 levels and GPx activity using spectrophotometric methods. The Hospital Anxiety and Depression Scale (HADS) was used to assess mental function. Both bolus and daily vitamin D supplementation were significantly associated with increased GPx activity and decreased IL-6 levels. Daily supplementation was additionally associated with a significant reduction in anxiety and depression scores. However, neither regimen was associated with improvements in cough, dyspnea, or fatigue. These findings suggest a potential association between vitamin D supplementation and improvements in antioxidant and neuropsychiatric parameters in PCC, possibly mediated by its immunomodulatory and antioxidant properties. Further placebo-controlled trials are warranted to determine whether these observed associations reflect causal relationships.

Spectrophotometric determination and removal of Rhodamine 6G from aqueous solutions using unfunctionalized multi-walled carbon nanotubes; with greenness and blueness assessment

ABSTRACT This paper conducted a comprehensive study of the one-step removal of Rhodamine 6 G (Rh 6G) dye from aqueous solutions using unfunctionalized multi-walled carbon nanotubes (MWCNTs). Unfunctionalized MWCNTs were characterised using FT-IR, FESEM, EDX, and mapping, both before and after adsorption. A UV-Visible spectrophotometric method at λmax 525 nm was validated for Rh 6G quantification (1–12 mg/L), exhibiting excellent linearity (R2 = 0.998), high accuracy (101.417 ± 1.687), and low RSD (1.664%). The limits of detection (LOD) and quantification (LOQ) were 0.380 mg/L and 1.152 mg/L, respectively.The optimal removal of Rh 6G on an unfunctionalized MWCNTs were found at an initial dye concentration of (2 mg/L), pH 10 at 308 K under shaking time of 10 min, using (0.001 g) of MWCNTs. A pH 10 value affected the adsorption of Rh 6G dye onto unfunctionalized MWCNTs. In this study, adsorption isotherms are described using means of Langmuir, Freundlich,Tempkin and Sips isotherms. The results indicated the adsorption isotherm could be well described with Freundlich model. The thermodynamic constants of the adsorption of the dye on unfunctionalized MWCNTs were calculated; the values indicated that a spontaneous and endothermic process was occurred. Kinetic studies aligned with the pseudo-second-order model. Unfunctionalized MWCNTs exhibit promising properties as a low-cost, easily applicable, and sustainable adsorbent, eliminating the need for harmful acid treatments and offering rapid adsorption compared to other adsorbents. In this work, the suggested analytical UV-Visible spectrophotometer method was evaluated using new greenness and blueness assessment tools: GAPI, ComplexGAPI, MoGAPI, ComplexMoGAPI, and BAGI. These tools showed appropriate green and blue scores. The GAPI and MoGAPI tools exhibited seven green colour, while both ComplexGAPI and ComplexMoGAPI tools exhibited 14 green colours with a high yield of 90.02%. The high BAGI score of 75 confirms that this adsorption method was strong applicability.

Assessment of Electrolyte Profiles and Kidney Function in Footballers at Rivers State University.

Background: Exercise leads to progressive loss of water and electrolyte from the body as sweat is secreted to promote heat loss and cool the body. Prolonged exercise could lead to alteration in electrolyte concentrations and this could negatively affect physiological processes. This study was aimed at assessing urine specific gravity, renal function and electrolyte disturbances among football players training at the football field in Rivers State university. A total of one hundred (100) footballers training at different football pitch in Rivers State University were involved in the study after prior informed consent was gotten from them. Blood samples were collected from all the subjects prior to the exercise from antecubital veins while post-exercise blood samples were collected within 5 minutes after the exercise. The blood samples were processed and analyzed for serum electrolytes, urea and creatinine using standard spectrophotometric methods, while the anion gap was calculated from the value of serum electrolytes obtained. Urine samples were also collected pre- and post- exercise and analyzed for specific gravity using the combi-10 lateral dipstick. Data was statistically analyzed using Statistical Package for the Social Sciences (SPSS) version 24. Results show no significant difference in mean concentrations of serum electrolytes (Na+, K+, Cl- and HCO3-), anion gap, urea and creatinine levels in pre exercising subject’s samples when compared with the post exercising samples (P> 0.05). However, the mean levels of the urine specific gravity increased significantly in post exercise period when compared with the pre exercising condition (P < 0.05). The findings of this work suggest that footballers have normal renal function, however they are dehydrated after one and half hour of soccer as seen in their elevated urine specific gravity. Players are therefore encouraged to increase fluid intake after soccer to maintain adequate hydration status necessary for optimal physiological processes.

ВАЛИДАЦИЯ АНАЛИТИЧЕСКОЙ МЕТОДИКИ КОЛИЧЕСТВЕННОГО ОПРЕДЕЛЕНИЯ АТЕНОЛОЛА В ПОРОШКАХ АПТЕЧНОГО ИЗГОТОВЛЕНИЯ ДЛЯ ДЕТЕЙ

Atenolol is a cardioselective β1-adrenoblocker with hypotensive, antianginal and antiarrhythmic effects. In paediatric practice, it is used for the treatment of heart defects and infantile haemangiomas, showing, compared to propranolol, fewer side effects from the central nervous system and bronchi. The pharmaceutical industry produces atenolol in 25, 50 or 100 mg tablets, while the most commonly used therapeutic dose of atenolol for the treatment of infants and young children is 0.5-1.5 mg/kg/day. The problem of atenolol dosing is solved by extemporaneous formulation. Doctors prescribe atenolol in the form of powder with dextrose or lactose. Extemporaneous manufacture allows maximum adaptation of the dosage to the needs of newborns and young children. A unified technique for quantitative determination of atenolol in powders with dextrose or lactose by spectrophotometric method was developed. The optical density of solutions was measured at a wavelength of 275 nm in cuvettes with a layer thickness of 10 mm. A 0.1 M solution of hydrochloric acid was used as a reference solution for standard solutions of atenolol and model powder solutions with dextrose; for model powder solutions with lactose, a reference solution containing 0.1 g of lactose in 100 ml of 0.1 M solution of hydrochloric acid was used. The experimental results are not burdened with systematic error. The relative standard deviation does not exceed 0.5%, the relative error of the mean does not exceed 0.4%. The proposed methodology is valid in terms of specificity, linearity and analytical scope of the methodology, intermediate (intra-laboratory) precision and correctness. The methods can be used in the practice of manufacturing pharmacies to assess the parameter ‘Quantitative Determination’.

Hydrothermal Humification of Spruce Greenery as an Environmentally Friendly Tool for Production of Synthetic Humic Substances and Evaluation of Reaction Dynamics

Peat is the main raw material for soil enhancers, but it is a slowly renewable fossil resource, and its extraction leads to significant greenhouse gas emissions, primarily in form of CO2 and CH4 with minimal NOx discharge. According to the Latvian State Forest Research Institute "Silava", 70 % of these emissions come from peat used in agriculture, contributing to a total of 1.709 kt CO2 equivalent. A sustainable alternative is spruce (Picea abies L.) greenery, a forestry by-product left behind after log extraction. This underutilized biomass, which can account for up to 50 % of a spruce tree’s dry mass, contains valuable compounds that can be extracted. The remaining material, rich in lignin, cellulose, and hemicellulose, can then be converted into synthetic humic substances through a hydrothermal humification process. This study promotes an end-of-waste approach by applying an innovative hydrothermal humification method to transform low-value forestry residues into synthetic humic substances that replicate the properties of natural peat humic substances for agricultural use. This conversion process generates significantly fewer greenhouse gas emissions than peat extraction and has the advantage of not requiring energy-intensive drying of biomass before synthesis. The findings of this research contribute to the development of high-value bioproducts from forestry residues, supporting circular economy principles within Latvia’s bioeconomy. Results demonstrate that spruce greenery biomass can be effectively converted into synthetic humic substances. The study examines the optimal conditions for hydrothermal humification, synthesis duration, and process temperature, to maximize the yield of synthetic humic acids, fulvic acids, and their low-molecular byproducts. The structural formation dynamics of synthetic humic substances were analyzed using advanced analytical techniques such as FTIR, 13C-CPMAS-NMR, and EPR spectroscopy, while the formation of fulvic acids and by-products were assessed using spectrophotometric methods such as total carbohydrates, total polyphenols, and their corresponding biological activities. This research provides essential insights into hydrothermal humification dynamics for the production of synthetic humic substances, their properties and future synthesis designs.

КОЛИЧЕСТВЕННОЕ ОПРЕДЕЛЕНИЕ ФЛАВОНОИДОВ КАЛЕНДУЛЫ ЦВЕТКОВ

Improving existing and developing new methods for analyzing biologically active substances of medicinal plants by reducing material and time costs is considered a priority task of modern pharmacognosy. Objective. Development of parameters for quantitative determination of calendula flower flavonoids. Matherials and Methods. Object of study – calendula flowers. We tested 16 methods for quantitative spectrophotometric determination of flavonoids from the State Pharmacopoeia of the Republic of Belarus on Calendula flowers. The basic method for developing the parameters for quantitative determination was selected by comparing the results obtained using the spectrophotometric method with high-performance liquid chromatography and by comparing the absorption spectra of rutin, caffeic acid standard samples and the extracts under study. We studied the effect of the following parameters on the optical density of the system: concentration of aluminum chloride solution in alcohol (70%, v/v); volume of aluminum chloride solution in alcohol (70%, v/v); volume of acetic acid in buffer solution S; volume of buffer solution S and duration of heating in a water bath. Statistical processing of the data was performed using Student's criterion. Results. It is shown that direct spectrophotometry is not suitable for quantitative determination of Calendula flower flavonoids, since hydroxycinnamic acids and unreacted reagents contribute to absorption. Based on the data of high-performance liquid chromatography and assessment of the ratio of optical densities of rutin and caffeic acid, a technique for quantitative determination of flavonoids was selected. When using this technique, the absorption spectra of rutin and calendula flower extracts coincide. The optimal parameters for spectrophotometric determination of calendula flower flavonoids are: concentration of aluminum chloride solution – 50 g / l; added volume of aluminum chloride solution – 8.0 ml; volume of acetic acid in buffer solution S – 2.5 ml; added volume of buffer solution S – 5.0 ml and duration of heating in a water bath – 4 min. Conclusion. Parameters for spectrophotometric determination of total flavonoid content in calendula flowers with recalculation to rutin have been developed. The choice of method for quantitative determination of calendula flower flavonoids has been substantiated.

Unveiling the Chemical Composition, Antioxidant, and Antimicrobial Potentials of Foeniculum vulgare Mill: A Combined In Vitro and In Silico Approach

This study on Foeniculum vulgare Mill., derived from seeds collected in Meknes (Morocco), evaluates in vitro and in silico the therapeutic potential of its extracts and essential oil through a comprehensive analysis of its phytochemical composition, as well as its antioxidant and antimicrobial activities. Aqueous extracts (E0), hydroethanolic extract (E1) obtained via Soxhlet, decoction (E2), and essential oil (EO) obtained through hydrodistillation were analyzed using HPLC/UV-ESI-MS and GC-MS, revealing a richness in phenolic and terpenic compounds. The quantification of total polyphenols, flavonoids, and tannins in aqueous and organic extracts was performed using spectrophotometric methods. Antioxidant activity was assessed through three methods: DPPH, FRAP, and Total Antioxidant Capacity (TAC). The antimicrobial activity of the essential oil and decoction was evaluated by microdilution in microplate assays. The aqueux extract was dominated by butyl ferulate (14.33%), while hydroethanolic extract contained chlorogenic acid (14.79%) and quercetin-3-glucuronide (13%). The extract (E2) was characterized by dihydrocaffeic acid (11.25%) and 3-O-caffeoylshikimic acid (11.08%), whereas the EO was primarily composed of fenchone (24.72%), trans-anethole (22.22%), and limonene (20.48%). Antioxidant assays (DPPH/FRAP/TAC) demonstrated decreasing efficacy as follows: EO exhibited the highest efficiency (IC50 = 51.45 μg/mL), followed by E1 (93.71 μg/mL), E0 (212.86 μg/mL), and E2 (397.41 μg/mL), confirming a correlation between phenolic composition and antioxidant activity. Furthermore, antimicrobial tests highlighted a pronounced fungicidal effect against Candida albicans (MIC = 3.13 mg/mL) and Aspergillus niger (6.25 mg/mL), contrasting with a more moderate inhibition of Escherichia coli and Staphylococcus aureus. Molecular docking simulations identified stable interactions between chlorogenic acid, quercetin-3-glucuronide, and microbial proteases, suggesting a synergistic inhibitory mechanism. This research validates the potential of F. vulgare as a source of bioactive molecules with promising applications in phytotherapy for managing oxidative stress and fungal infections, while emphasizing the need for clinical studies to confirm these effects in vivo.

“All-in-a-tube” detection of RDX and TNT: old silver mirror reaction revived for nitro-explosive quantification

Inspired by analyte-induced in situ formation/growth of silver nanoparticles (AgNPs), the traditional Tollens’ reagent of diamminesilver(I) complex cation [Ag(NH3)2]+ was shown to be capable of detecting explosives. Thus, a color test based on in situ formation of AgNPs was developed for 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT). The resultant yellow-colored AgNPs were characterized using UV–visible spectrophotometry, scanning transmission electron microscopy, and dynamic light scattering measurements. The system displays turn-on absorbance behavior with RDX and TNT, yielding detection limits of 50.3 and 67.2 nmol L−1, respectively. The assay could distinguish between RDX and TNT using a simple extraction-based recovery procedure. Good recoveries for RDX and TNT were obtained from real (Composite B, Composite A5, and Octol) and synthetically prepared formulations. Method validation was performed by statistically comparing the analytical results obtained by the reference liquid chromatography-tandem mass spectrometric method applied to RDX standards and RDX-contaminated soil samples. As a novelty of this system, direct spectrophotometric detection of RDX through its decomposition product, formaldehyde, was successfully performed for the first time. Compared with the widely used indirect spectrophotometric methods based on nitrite formation from RDX degradation, the system is superior in that it does not require pre-hydrolysis of RDX and does not respond to 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX). It is also noteworthy that the system responds to TNT in a way that constitutes an innovative alternative to the existing mechanism of Meisenheimer/Janowsky complex formation in the literature.Graphical

Sustainable Cultivation of Galdieria phlegrea in an IoT-Integrated Twin-Layer Photobioreactor: System Design, Growth Dynamics, and Isotopic Perspective

This study showcases an attached-biomass system based on twin-layer technology for cultivating Galdieria phlegrea using municipal wastewater, equipped with a smart sensor system for the remote monitoring of operational parameters. From an industrial scale-up perspective, the system offers high scalability, with low impact and operating costs. Mathematical approximation modelling identified the optimal growth conditions across five experiments. The theoretical yield was estimated to reach 1 kgDW/m2 of biomass within two months. Integrated use of isotopic mass spectrometry and spectrophotometric methods allowed us to study the metabolic strategies implemented by the algal community during the best growth condition at different resolutions, showing an increase in the nitrogen concentration over time and a favourable affinity of the organism for nitrogen species that are commonly present in the urban effluent. SEM studies showed a clean algal biofilm (free of foreign organisms), which could guarantee usage in the high economic potential market of biorefineries.

Phenolic Compounds in Flowers and Herb of Achillea millefolium L.: Histochemical and Phytochemical Studies.

The herb and flowers of yarrow (Achillea millefolium) are sources of multiple bioactive secondary metabolites used in medicine and cosmetology. This study aimed to establish the location of phenolic compounds in tissues of flowers and stems of A. millefolium via light and fluorescence microscopy and histochemical assays. The spectrophotometric and HPLC methods were deployed to quantify total phenolic compounds (PC), phenolic acids, and flavonoids in extracts from flowers and herb, whereas the LC-QTOF-MS method was used for their qualitative analysis. The results demonstrated that PC occurred in external and internal tissues of yarrow stems, petals, and other parts of the flower, as well as in involucral bracts. Qualitative phytochemical analyses demonstrated ca. 16% more PC and flavonoids in flowers than in the herb. This analysis allowed identifying 48 PC. A higher number of PC was identified in flowers than in herbs, with rosmarinic acid followed by chlorogenic acid being the major polyphenols found in both sample types. One of the flavonoids, namely luteolin, was detected in significantly higher quantities in the flowers than in the herb. This study results provide new data on the location of PC in flowers and stems of A. millefolium as well as extend knowledge on their contents in the raw material of yarrow.

Evaluation of total phenolic, flavonoid contents, antioxidant and antibacterial activity of leaf extracts from Rhus vulgaris

Rhus vulgaris, a plant known for its rich composition of polyphenols and flavonoids, serves as a potent agent against oxidative stress and various diseases, including cancer. The aim of this study involved extraction using the solvents n-hexane, acetone, and 80% aqueous methanol, phytochemical screening, and antibacterial testing. The total phenolic and flavonoid content was quantified using Folin-Ciocalteu and aluminum chloride spectrophotometric methods. The antioxidant activity was evaluated via the DPPH radical scavenging assay. The study found that the extracts predominantly contain alkaloids, phenols, flavonoids, glycosides, tannins, steroids, carbohydrates, and anthraquinones. Compared to the standard, the methanol extracts showed better inhibitory zones. Results revealed that total polyphenols ranged from 5.82 ± 0.6 to 83.23 ± 0.6 mgGAE/100 g, and the flavonoid content varied between 2.21 ± 0.34 to 23.47 ± 0.87 mg CE/100 g. R. vulgaris leaf extracts had excellent antioxidant activity, ranging from 0.756 ± 0.8 to 131.56 ± 0.6 mgAAE/g sample. The R. vulgaris 80% methanolic extract displayed the highest phenolic and flavonoid concentrations as well as a powerful antioxidant capacity. Based on these findings, it is possible that R. vulgaris could be turned into a natural antibiotic that works well for treating a variety of illnesses, both incurable and curable.

Cyclic voltammetry for antioxidant assessment of moth bean protein hydrolysates: a comparative study with spectrophotometric methods

Cyclic voltammetry for antioxidant assessment of moth bean protein hydrolysates: a comparative study with spectrophotometric methods

Utility of green chemistry for spectrofluorometric and spectrophotometric analysis of vericiguat via reaction with erythrocin B

Food colorant Erythrosine B (EB) is an antiviral xanthene dye with a wide range of uses as a colorant in cosmetics and medications. Its availability, affordability, quick labeling, and high sensitivity make it an excellent choice for spectrofluorometric and spectrophotometric examination of amine-based medications. Two quick and accurate spectrophotometric and spectrofluorometric methods were developed for the estimation of vericiguat in this case. To create an ion-pair complex at pH 4 using the Britton Robinson buffer, the suggested methods relied on the interaction between the amino groups of the medication under study and the phenolic group of EB. The quenching effect of the vericigaute drug of EB at excitation/emission wavelengths of 530.0/550.0 nm. This method demonstrated a limit of detection (LOD) of 0.036 µg/mL and a limit of quantification (LOQ) of 0.110 µg/mL, showing rectilinear response in the concentration range of 0.05–0.5 µg/mL. Additionally, the absorbance of the produced ion-pair complex was evaluated using the colorimetric approach at 560 nm, displaying a linearity range of 0.5–10.0 µg/mL with LOD = 0.428 µg/mL and LOQ = 1.298 µg/mL. The greenness of the developed approaches was determined by GAPT and AGREE software for evaluating the suggested methods.

Effects of different doses of Ganoderic Acid A on nociceptive behaviour and inflammatory parameters in polyarthritic mice rheumatoid arthritis model

The frequency of autoimmune diseases such as rheumatoid arthritis is increasing annually. Current treatments for these diseases cause new problems due to their side effects. In this study, we investigated the impact of Ganoderic Acid A (GAA), a potent anti-inflammatory herbal molecule, to evaluate the potential efficacy of GAA in alleviating Rheumatoid arthritis (RA)-associated clinical and histopathological manifestations. 40 Balb/c male mice were randomly divided into five groups (n = mice number per each group) as control (C), acetic acid (AA), rheumatoid arthritis (RA), low dose GAA (LGA) and high dose GAA (HGA) groups. Collagen emulsion was applied intra-articularly (ia), and complete Freund’s adjuvant (CFA) was applied subcutaneously (sc) to the RA and GA groups to induce an experimental model of rheumatoid arthritis. Other groups were given physiologic saline (PS) or AA at the same dose and in the same way. The procedures were repeated on the 22nd day; however, incomplete Freund’s adjuvant was applied to the RA and GA groups instead of CFA. PS was given to groups C, AA and RA for 9 days starting from the 22nd day; GAA was applied to the LGA (20 mg/kg) and HGA (40 mg/kg) groups by gavage. We evaluated body weight, arthritis score, knee temperature, knee circumference, behavioural assessment of pain, gait, tail-flick test, hot plate test, locomotor activity test, lower extremity index, spectrophotometric and histopathological evaluation methods, respectively. Compared to the RA group, the clinical arthritis score was reduced in the HGA group (p < 0.05). GAA significantly reduced knee temperatures and knee circumference, with changes in hot plate scores and tail flip test response. In the GAA groups, serum concentrations of AST, IL-6, TNF-α, NFkB were reduced, and joint damage and arthritis scores were also reduced histologically (p < 0.05). The results of this study suggest that the arthritis regressed with GAA treatment. Edema and inflammation were found to be reduced in the GAA groups compared with the RA group. GAA treatment resulted in significant improvements in behavioural activity, reduced inflammation and the damage to cartilage and bone structure and had an antinociceptive effect.

Comparative Quantitative Study of Acetyl Salicylic Acid in Aspirin Samples Using Spectrophotometry and Volumetric

This study focuses on the quantification of acetylsalicylic acid (ASA) in aspirin tablets using two analytical approaches: back-titration and spectrophotometric analysis. Significant variations in ASA concentrations were observed across different samples. The back-titration method recorded concentrations ranging from 33.68% to 75.27%, while spectrophotometric analysis yielded values between 26.27% and 74.65%. These discrepancies highlight potential factors such as formulation inconsistencies, manufacturing quality, or chemical interactions during analysis. A comparative evaluation of the two methods reveals that the spectrophotometric method demonstrated higher precision and ease of execution, making it suitable for routine pharmaceutical analysis. However, both methods showed limitations in accuracy. The findings suggest variability in ASA concentrations among different commercial brands, which remain largely within official standards but warrant further investigation to ensure consistency and efficacy. The study underscores the need for refining analytical methods to enhance reliability and calls for improved manufacturing protocols to maintain quality control in pharmaceutical products.

Deuterium isotope effects in mechanistic studies of biotransformations of l-tyrosine and p-hydroxyphenylpyruvic acid catalyzed by the enzyme l-phenylalanine dehydrogenase

Abstract The mechanisms of the reversible oxidative deamination of l-tyrosine to p-hydroxyphenylpyruvic acid and reductive amination of phenylpyruvic acid to l-phenylalanine, both catalyzed by the enzyme l-phenylalanine dehydrogenase (PheDH, EC 1.4.1.20), were investigated using the kinetic isotope effect (KIE) and solvent isotope effect (SIE) methods. The values of deuterium kinetic effects in the 2-position of l-tyrosine and KIE in the (3S)-position of phenylpyruvic acid and solvent isotope effects for both reactions were determined using the non-competitive spectrophotometric method. Some mechanistic details of these biotransformations were discussed.

Lipidemic Status in Indo-Aryan (Bangladeshi) and Cushitic (Somali) Adults: A Comparative Pilot Study

Assessment of lipidemic status is crucial for predicting cardiovascular risk. However, few studies have compared lipid profiles in our population with other ethnicities. In this pilot study, we investigated and compared the lipidemic status of individuals of Indo-Aryan (Bangladeshi) and Cushitic (Somali) descent to explore potential genetic, lifestyle, and environmental influences on lipid metabolism. We enrolled sixty participants (30 Bangladeshi and 30 Somali) and measured the lipid profiles - including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), triglycerides (TG) using standard spectrophotometric methods, apolipoproteins using standard immunoturbidimetric methods while the formula was applied to calculate LDL cholesterol (LDL-c). Bangladeshi subjects were older (26.1 ± 2.1 vs. 23.4 ± 2.3 years, p &lt; 0.001) and had a higher body mass index (22.6 ± 3.2 vs. 19.4 ± 2.6 kg/m², p &lt; 0.001) compared to Somali subjects. Compared to Somali, the percentages of HDL-c dyslipidemia was higher (80.0% vs. 43.3%, p = 0.017), followed by hypertriglyceridemia (23.3% vs. 3.3%, p = 0.052) and hypercholesterolemia (20.0% vs. 6.7%, p = 0.254) and elevated LDL-c (16.7% vs. 6.7%, p = 0.424). TC and LDL-c levels did not differ significantly between the groups but higher triglyceride levels were observed in Bangladeshi individuals (145±113 mg/dL vs. 78±36 mg/dL, p = 0.003) compared to the Somali group. ApoA1 levels were similar between groups, but ApoB levels were higher in the Bangladeshi group, though this difference was not statistically significant (p = 0.408). On adjusting confounding variables, lipids and lipoproteins showed no significant association with ethnicity except HDL-c (β = 5.023, p = 0.020). In conclusion, despite similar apolipoprotein A1 and ApoB levels, the Bangladeshi ethnic group has lower HDL cholesterol compared to Somali adults, suggesting a greater cardiovascular risk relative to the Somali group.