Current Analytical Chemistry - Volume 22, Issue 1, 2026

Elevated blood cholesterol has been established as a major risk factor for atherosclerotic cardiovascular disease (ASCVD). Adults with hyperlipidemia have a significantly increased risk of developing cardiovascular diseases (CVD). First-line treatments for hyperlipidemia include statins, which help raise HDL-C levels in cases of severe and familial hypercholesterolemia and decrease LDL-C and TG levels. Numerous adverse effects on muscles have been associated with statins, such as asymptomatic elevations in blood creatine kinase activity and potentially fatal rhabdomyolysis. Non-statin drugs are advised for people whose very high cardiovascular risk or heterozygous familial hypercholesterolemia make statin therapy insufficient. A novel lipid-lowering medication with a distinct mode of action is bempedoic acid.

Elevated blood cholesterol is a significant risk factor for atherosclerotic cardiovascular disease (ASCVD). Individuals with hyperlipidemia are at a higher risk for developing cardiovascular diseases. Statins are the primary treatment for hyperlipidemia, raising HDL-C levels and lowering LDL-C and TG levels. However, statins can adversely affect muscles, including muscle-related complications like increased blood creatine kinase activity and rhabdomyolysis. Therefore, non-statin drugs may be recommended for individuals. Bempedoic acid is a brand-new, first-in-class, oral small molecule that inhibits cholesterol manufacturing like statins, consequently reducing low-density lipoprotein cholesterol (LDL-C) through activating LDL receptors.

This study offers helpful information on how to utilize bempedoic acid to decrease LDL-C, as well as recommendations for which individuals could benefit and safety monitoring tips during therapy. A novel family of drugs called bempedoic acid is identified as a prodrug that becomes bempedoyl-CoA in the liver via an enzyme called very longchain consisting of acyl-CoA synthetase 1. Bempedoic acid can control cholesterol metabolism. Low-density lipoprotein cholesterol levels appeared to be dramatically reduced by bempedoic acid, according to clinical investigations. The toleration of bempedoic acid was good.

A cardiovascular outcomes trial is now evaluating bempedoic acid to determine its impact on major cardiovascular events in patients with or at high risk for cardiovascular disease and statin intolerance.

This review describes the chemistry, mechanism of action, pharmacokinetics, analytical potential, and safety of bempedoic acid. Bempedoic acid is an effective and often well-tolerated drug used to further reduce LDL-C levels in patients taking the maximum dosage of tolerated statins or to control LDL-C levels in persons who can not take statins. The results of the CLEAR (Cholestrol Lowering via bempedoic acid, an ACL inhibitory Regimen) Outcomes research, which is looking into whether bempedoic acid might reduce the frequency of serious cardiovascular events, are expected in 2025.

This study introduces an innovative two-step approach to fabricate a high-performance Ni2O3/NiO/rGO nanocomposite photocatalyst. The process synergistically combines solvothermal precursor synthesis with calcination and high-energy ultrasonic irradiation, enabling the in-situ formation of a thin Ni2O3 layer on NiO quasi-sphere nanoparticles anchored to a reduced graphene oxide (rGO) matrix.

The incorporation of rGO significantly enhances charge separation, resulting in a dramatic increase in active surface area from 17.1 m²/g to 131 m²/g, and a substantial improvement in the photocatalytic degradation of the resilient Fluorescein dye—achieving an 81% degradation rate under UV light, compared to 36% with pristine NiO.

Comprehensive characterization, including FTIR, XRD, and XPS analyses, confirmed the NiO-Ni2O3 interface transformation, successful reduction of graphene oxide, and critical interactions between NiO and Ni2O3.

This study highlights the promising potential of the Ni2O3/NiO/rGO nanocomposite for environmental remediation, particularly in the degradation of persistent organic pollutants.

This is the first report on the development and validation of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC)-densitometric methods for the identification of linoleic acid (LA) in petroleum ether extract (PEE) of Euphorbia neriifolia (EN) stem (ST), latex (LX), and bark (BA).

Chromatographic analyses were performed on silica gel-G and silica gel 60 F254 plates.

The chromatographic analyses revealed better spots and well-separated peaks of LA with retention factor (Rf) values at 0.54 (ST), 0.40 (LX), and 0.64 (BA), respectively. The linearity of the calibration curve ranges from 10-50 ng/spot (ST), 10-100 ng/spot (LX), and 50-200 ng/spot (BA). The proposed method was characterized by better accuracy, better robustness, and good precision, ranging from 0.173 to 0.372% (intra-day) and 0.185 to 0.205% (inter-day). The value of the limit of detection and quantification equal to 1.04 and 3.16 ng/spot in ST, 0.87 and 2.64 ng/spot in LX, and 0.177 and 0.53 ng/spot in BA determined the sensitivity of the method. In the obtained chromatogram, no peak was observed other than the LA which determined the specificity of the method. The % RSD of < 2% after periods of 12, 24, 36, 48, and 72 h determined the stability of standard LA.

Thus, the fingerprinting method is valuable in determining the adulterants and in routine quality control of formulations and herbal drugs.

Metoclopramide is a widely prescribed antiemetic drug. Its analysis in pharmaceutical formulations often involves procedures using high amounts of toxic chemicals.

A method based on micellar liquid chromatography to determine metoclopramide hydrochloride in several oral dosage forms has been developed.

The drug was resolved from matrix compounds within 6 min using a C18 column with isocratic elution at 1 mL/min utilizing a solution of 0.10 mol/L sodium dodecyl sulfate – 6% 1-pentanol phosphate buffered at pH 7 as mobile phase, and detection by absorbance at 210 nm. Samples were dissolved or diluted in the mobile phase and directly injected; thus, only one solution had to be prepared for the entire procedure. Besides, it contained mainly harmless chemicals and a minimal amount of organic solvent.

The procedure was validated by the International Council of Harmonization guidelines and the results were: specificity, calibration range (0.5 – 5.0 mg/L), linearity (r² > 0.9990), trueness (98.1 – 100.3%), precision (< 0.7%), robustness, carry-over effect, and system suitability. It was used to analyze commercial samples. Otherwise, it was found the influence of the surfactant on elution strength was nearly three times stronger than that of 1-pentanol.

The procedure was reliable, easy-to-conduct, safe, eco-friendly, short-time, widely available and highly sample-throughput, and then useful for routine analysis of metoclopramide-based dosage forms in pharmaceutical quality control.

4-n-butylresorcinol (4nBR) was widely used in the treatment of chloasma and skin whitening cosmetics. As a decolorizing agent, it can effectively control the activity of tyrosinase. Market regulatory authorities require truthful labeling of ingredients in cosmetics. Therefore, the quantitative determination of 4nBR is of great practical significance.

At present, the main detection method of 4nBR reported in the literature is HPLC. Compared with the HPLC method, optical methods offer several advantages, including low cost, and simplicity, which make them suitable for on-field detection applications. A convenient spectrophotometric method was established for 4nBR detection.

Fe³⁺ can oxidize the common colorless chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxTMB. Based on the fact that 4-n-butyl resorcinol (4nBR) can reduce oxTMB, a convenient and rapid spectrophotometric method for the determination of 4nBR was proposed.

Under the optimum conditions, the absorbance at 652 nm has a good linear relationship with the concentration of 4nBR in the range of 1.2 - 16 μM. The linear equation for the detection of 4nBR was ΔA = 0.0546 c (μM) - 0.0026 (r²=0.9962), and the detection limit was 0.33 μM. The accuracy of this method is comparable to that of HPLC.

This method has good selectivity for 4nBR and good anti-interference ability for common additives in cosmetics. The proposed method can be applied to the determination of 4nBR in thereal samples.

The detection and extraction of trace metal ions, particularly copper(II), are critical for environmental monitoring and industrial processes. Calixresorcinarene, with its unique cavity structure, offers excellent platforms for designing selective chemosensors and extractants. Functionalization of calixresorcinarene with azo groups can enhance their chromogenic properties, enabling both extraction and detection in a single step.

This study aimed to evaluate its (Azocalix[4]resorcinaren) efficacy as a selective chemosensor for the liquid-liquid extraction and spectrophotometric determination of Cu(II) ions.

The ability of the dye to selectively extract Cu(II) ions from aqueous solutions was investigated via liquid-liquid extraction experiments. The dye-Cu(II) complex formation was monitored by UV-Vis spectrophotometry, with systematic optimization of experimental conditions, including pH, solvent system, and extraction duration.

The synthesized azocalix[4]resorcinarene dye exhibited a pronounced selectivity towards Cu(II) ions, forming a stable, colored complex. The complexation induced a distinct bathochromic shift in the absorption spectrum, allowing for precise spectrophotometric detection. Optimal extraction was achieved at a specific pH and solvent combination, with the method demonstrating a low detection limit and high sensitivity. The dye showed minimal interference from other metal ions, confirming its selectivity for Cu(II).

The tetrafunctionalized azocalix[4]resorcinarene dye is a highly effective chromogenic agent for the selective extraction and detection of Cu(II) ions. Its robust performance in both extraction efficiency and spectrophotometric detection underscores its potential utility in environmental analysis and industrial applications where trace metal detection is crucial.

The use of microwave digestion coupled with inductively coupled plasma mass spectrometry (ICP-MS) to measure the content of metal elements in Citrus medica L. var. Sarcodactylis from different regions serves as a reference for tracing its origin and provides a basis for quality control and safety assessment of its heavy metal content.

After microwave digestion of Citrus medica samples, metal element contents from different regions were determined using ICP-MS, with methodological investigations conducted. A diverse statistical analysis was performed to explore the relationship between geographical distribution of Citrus medica and metal element contents. Additionally, safety assessments were conducted using single factor pollution index and Nemerow comprehensive pollution index methods for several heavy metal elements.

The contents of elements such as Mg, Fe, and Al are relatively high in Citrus medica. Characteristic differences in elements like Al, Ni, Mg, Cr, Sr, and Zn among samples from different regions are evident. Principal component analysis (PCA) indicates that samples from Sichuan Province can be clustered by origin. Elements including Ni, Co, Al, As, Cu, and Fe may contribute significantly to distinguishing Citrus medica from different regions. Pollution assessments for several heavy metals conclude that Citrus medica samples are safe and clean.

The ICP-MS method is rapid and accurate, capable of simultaneous measurement of multiple metal elements in Citrus medica. Combined with multivariate statistical analysis, it facilitates origin tracing studies of Citrus medica from various regions, particularly enabling effective differentiation of those from Sichuan Province.

Reactive oxygen species (ROS) in biological systems can damage cells by oxidizing membrane lipids, proteins, DNA, and enzymes. Antioxidants are essential in mitigating these effects and are extensively used in nutraceuticals, functional foods, and dietary supplements. They play a crucial role in the neutralization of reactive oxygen species (ROS), thereby preventing cellular damage, DNA mutations, and the development of diseases such as cancer, diabetes, and coronary heart disease. To effectively mitigate these diseases, it is essential to develop rapid and efficient methodologies for assessing antioxidant activity.

The smartphone colorimetric biosensor system and DPPH radical scavenging assay were developed and employed to determine the antioxidant activity of various beverages.

A comparative analysis of the DPPH radical scavenging assay for beverages was conducted using a UV-Vis spectrophotometer (R²=0.9907) and a smartphone-based colorimetric biosensor application (R²=0.9929). The results demonstrated a strong correlation between the two methods across all beverages tested. Specifically, the antioxidant capacities were 15% for orange juice, 21% for Miero Fiber, and 12% for Coca-Cola. The linear correlation across different concentrations for all beverages showed an R² value of 0.9929, validating the accuracy and effectiveness of the smartphone-based detection system.

This study highlights the practicality of using smartphone-based technology for detecting antioxidants and opens avenues for more accessible and faster health diagnostics. By utilizing smartphone biosensor technology, the accessibility of antioxidant assessments is enhanced, further promoting the adoption of preventative health strategies.

Ubrogepant is a regulated peptide receptor antagonist associated with the calcitonin gene, granted approval in the United States for the specific treatment of migraine headaches.

An impurity found in the alkali hydrolysis of drug dosage forms has a structure very similar to that of ubrogepant. This research aims to characterize this analogous impurity utilizing NMR and LC-MS spectroscopy tools. Moreover, it is critical to develop an extremely sensitive and superior resolution analytical procedure for identifying and determining the amount of analogous impurity in pharmaceutical products.

The ubrogepant impurity was identified using an optimized chromatographic method that relies on reversed-phase HPLC with UV detection. This technique utilized a charged surface hybrid (CSH) technology column operating in gradient elution mode. A mixture of A-channel (0.1% trifluoroacetic acid) and B-channel (acetonitrile and water, 80:20% v/v) constituted the eluent. The analogous impurity was isolated through fraction collection, purified using flash chromatography, and characterized using NMR (¹D and ²D) and LC-MS.

The analogous impurity was successfully separated from the ubrogepant peak with a resolution above 2.0. The concentration of the impurity was approximately 10% compared to the ubrogepant peak after alkaline stressing at room temperature for 30 minutes. NMR (¹D ¹³C NMR and ¹H NMR, ²D HMBC, HSQC, NOESY, and COSY) and LC-MS analysis characterized the ubrogepant impurity, revealing it to be an epimer of ubrogepant. The developed approach was highly sensitive, allowing for the quantification of the ubrogepant impurity even at a concentration of 0.2 µg/mL.

The approach demonstrated a remarkable degree of precision, linearity, specificity, and accuracy. This new impurity deserves special attention because of its striking similarity to the active ingredient, ubrogepant.

Imipenem and meropenem are the carbapenem antibiotics most commonly used for the treatment of severe bacterial infections. Their stability behavior, which focuses on degradation products, has been continually reported. Strategies based on in silico prediction have been explored as an additional tool that provides additional information about drug stability.

A comparison between experimental and predictive data, with a focus on stability and degradation products, was performed by examining the literature data and the in silico results. The experimental data were obtained from the literature throughdatabase searches. The in silico degradation prediction was performed through the software Zeneth 9.0, which strictly focused on degradation products. With a focus on stability, degraded samples of meropenem and imipenem were investigated in terms of biological safety, applying an in vitro cytotoxicity assay by MTT reduction and neutral red uptake.

From the literature survey, it was found that 11 major degradation products for both carbapenems mainly formed from modifications on the b-lactam ring and dimerization. By using the Zeneth software, a large number of substances were predicted, considering the probability of occurring and the selected stressors. Even in low numbers, the comparative results indicated similarity in 4 degradation products, with high probability. About cytotoxicity, the cell viability by MTT assay was significantly reduced for imipenem samples degraded during 4 hours. For meropenem, applying neutral red uptake assay, a reduction of cell viability was observed in samples stored for 4 hours.

Drug stability assay includes different approaches, which can be used favorably from the interaction between all areas of interest, including experimental practice and predictive modelling assay.

Cocrystal engineering of Telmisartan (TEL, a poorly soluble antihypertensive agent) has been undertaken to improve its solubility for the last few years. However, apart from a few handpicked attempts, none of the attempts have been able to improve its solubility by more than 3-5 fold and augment its dissolution by more than 80%.

Addressing these shortcomings, herein, we have designed a novel Telmisartan-maleic acid (TM) cocrystal first by rational modelling with solvent-induced molecular mechanics (SIMM), ab initio based system optimization, descriptor analysis, and finally translating to cocrystals by wet grinding-gradient solvent evaporation method.

Modelling revealed that binary solvent compared to single solvent imparted critical dynamics to seeding the co-crystallite and its structural archipelago. From single solvent to binary solvent, hydrogen bonding to nucleophilic addition of the coformer/s to the central ring revealed a crucial role in assigning the system geometry. The molecular descriptor plot of the generated subsystems (optimized by HF-SCF/def2-SVP method) showed that telmisartan: maleic acid molar ratio <=1:2 under ionizable conditions bear optimum hydrophilicity/hydrophobicity balance. Tonto-guided energy calculation revealed O--H and H--H as the predominant interactions for the crystal packing.

In translational research, our designed TM cocrystal (molar ratio 1:1.5 to 1:2, binary solvent dynamics) exhibited solubility improvement by more than 9 fold in water and showed to release about 92.19% of drugs within 2h (120 min), which superseded the previous reports in this field so far.

This study describes the development of methodologies for the isolation, identification, and quantification of betulinic, oleanolic, and ursolic acids in extracts from Eriope blanchetii (Lamiaceae) and Davilla rugosa (Dilleniaceae).

Betulinic, oleanolic, and ursolic acids are compounds with biological activities and commercial and technological uses. Developing methodologies for their separation from natural sources are relevant once their synthesis is not easy.

Development of conventional methodology for quantifying and isolating pure betulinic acid in chloroform extracts of D. rugosa stems and developing methods for obtaining and quantifying oleanolic, ursolic, and betulinic acids from organic extracts.

A complete validation “in-house” for the chromatographic method was performed, and different techniques of extraction – maceration under heating vs. microwave-assisted extraction (MAE) conditions were compared. Davilla rugosa stems were employed as the source of pure betulinic acid, and this compound was obtained in a reasonable yield (~ 2.4 x 10^-2% dry weight).

Chromatographic analysis of the E. blanchetii extracts indicates betulinic acid occurs in higher concentrations in the leaves (5.53% dry weight), followed by lower concentrations in other plant parts, together with two other triterpene acids. HPLC analysis of extracts obtained by MAE extractions and maceration of E. blanchetti indicated that MAE is more efficient than maceration under heating in relative yield. The HPLC-validated method was rightly selective and accurate, presenting good linearity (R² = 0.9993), robustness, and recovery rate values with acceptable limits (LD = 5.9914; LQ = 18.1557; µg mL^-1).

MAE was the most efficient methodology than maceration under similar conditions. Furthermore, different parts of E. blanchetii and D. rugosa are affordable sources of bioactive betulinic acid.