Search Results (6,713)

Background/Objectives: Ursodeoxycholic acid (UDCA) is a bile acid widely used for the treatment of cholestatic liver diseases; however, its poor aqueous solubility represents a major limitation for the development of oral liquid formulations, particularly in pediatric patients requiring accurate and flexible dosing. This study aimed to develop and characterize a fully solubilized extemporaneous UDCA oral formulation using the ready-to-use vehicle Wagner, with particular emphasis on the role of hydroxypropyl-β-cyclodextrin (HP-β-CD) as a solubilizing excipient. Methods: Phase-solubility studies, Job’s plot analysis, and ¹H NMR spectroscopy were performed to investigate the host–guest interaction between UDCA and HP-β-CD, confirming the formation of a stable 1:1 inclusion complex responsible for a marked increase in drug solubility. The aqueous solubility of UDCA increased from approximately 0.02 mg/mL in water to 31 ± 1 mg/mL in the Wagner base containing HP-β-CD, compared to ~10 mg/mL in the corresponding cyclodextrin-free vehicle. Chemical stability was evaluated using an HPLC method adapted from the European Pharmacopoeia, employing dual detection (refractive index and photodiode array detector) to ensure specificity and stability-indicating capability. Results: The UDCA solution (20 mg/mL) remained chemically stable for at least 4 months under refrigerated (4–8 °C) and room temperature (25 °C) conditions, with only moderate degradation observed at 40 °C. Physical stability studies confirmed the absence of precipitation, phase separation, or significant pH variations under all storage conditions. Conclusions: Wagner-based formulation enabled the development of a stable and homogeneous UDCA oral solution, providing a complementary formulation strategy to conventional suspension-based preparations. This approach represents a robust and patient-oriented strategy for extemporaneous compounding, particularly suitable for pediatric use. Full article

An efficient catalyst for the reaction of ethanol–acetaldehyde into 1,3-butadiene (EATB) is prepared through the grafting of zirconia into a zeolite Beta lattice. The grafting is achieved through the dealumination of a zeolite framework by acid treatment followed by zirconia impregnation, leading to the substitution of aluminum in the zeolite framework by zirconia. The catalyst with zirconia grafted into the zeolite framework promotes desirable catalyst properties like high zirconium dispersion, stability, and the close proximity of Lewis acid, Bronsted acid, and medium basic sites. The phase, the coordination of zirconia, the location of the active center and the cooperative synergism were elucidated through various characterization techniques, including X-ray diffraction, Raman spectroscopy, N₂ adsorption, UV–vis spectroscopy, XPS, ²⁹Si MAS NMR, NH₃-TPD, Py-IR, CO-IR and CO₂-TPD. The catalytic results show that a suitable phase and content of zirconia were needed to improve the ethanol–acetaldehyde conversion, butadiene selectivity and catalyst stability. Among the catalysts, m+t-ZrO_x-Beta-H₂O-9020 (m = monoclinic, t = tetragonal ZrO₂ phase) achieved the best butadiene selectivity of 82–73% at the conversion of 100–66%, run over 200 h. The results allow us to propose a Lewis acid–medium basic pairing for the Si–O–Zr–O–Si group, where the adjacent Si-OH is the active center for reactions. Full article

Cosmetic preservatives should have reduced percutaneous absorption to lower the risk of systemic exposure and skin irritation. In this work, previously synthesized galactosylated derivatives of common cosmetic preservatives were comparatively evaluated for transdermal permeation and preliminary toxicity. Escherichia coli β-galactosidase was used to enzymatically modify several of the commonly used cosmetic preservatives to produce their corresponding galactosylated derivatives: benzyl alcohol β-d-galactopyranoside 7, 2-phenoxyethanol β-d-galactopyranoside 8, chlorphenesin β-d-galactopyranoside 9, 1,2-hexanediol β-d-galactopyranoside 10, 1,2-octanediol β-d-galactopyranoside 11, and 2-phenylethyl β-d-galactopyranoside 12. HPLC and NMR spectroscopy were used to analyze the previously synthesized derivatives. The Franz diffusion cell assay was used to evaluate skin penetration. 2-Phenoxyethanol (PE), chlorphenesin (CPN), and 2-phenylethanol (PhE), showed measurable skin penetration, with flux values ranging from 3.82 to 7.34 µg·h⁻¹·cm⁻² and permeability coefficients (Kp) between 1.38 and 3.00 × 10⁻³ cm·h⁻¹. In contrast, their galactosylated derivatives showed markedly reduced permeation under the same experimental conditions. Moreover, brine shrimp lethality assays indicated that galactosylated derivatives had significantly higher LD₅₀ values (1.6–2.1 mg/mL) than their parent compounds (0.1–0.79 mg/mL), suggesting lower cytotoxicity. These findings suggest that enzymatic galactosylation can significantly decrease skin permeability and the toxicity of cosmetic preservatives, highlighting its potential approach to improve the safety of cosmetic components. Full article

4-Methyl-N-(4-methylbenzyl)-N’-(4-methylbenzylidene)benzenesulfonohydrazide was synthesized via N-alkylation. The compound was characterized by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Its molecular structure was unambiguously established by single-crystal X-ray diffraction analysis. The comprehensive spectral and crystallographic data conclusively verify the successful synthesis and structural integrity of this newly prepared compound. Full article

Monoclonal antibodies (mAbs) have been the subject of extensive study in recent years due to their recognition as highly promising therapeutic molecules offering high specificity and a low risk of side effects. Monitoring the structure of these molecules is crucial for developing new therapeutics, characterizing interactions with antigens or receptors, and explaining potential changes in activity between antibody production batches. However, commonly used biophysical approaches provide only low-spatial-resolution information, and conventional structural biology techniques such as crystallography and cryo-electron microscopy (cryo-EM) are difficult to apply to these highly dynamic proteins. Solution nuclear magnetic resonance (NMR) spectroscopy is the method of choice for structural studies of flexible proteins at atomic resolution; however, it has traditionally been limited to low-molecular-weight biological systems. In this review, we present recent advances in NMR spectroscopy and advanced isotopic labeling methods that have enabled the atomic-resolution study of both the crystallizable (Fc) and antigen-binding (Fab) fragments of antibodies. We show how NMR is becoming a powerful tool for investigating full-length mAbs at an atomic level, opening up new possibilities for the characterization and in-depth quality control of therapeutic antibodies in solution. Full article

Azolium-derived metallates are well-established intermediates in metal–N-heterocyclic carbene chemistry; however, their potential as standalone therapeutic agents remains largely unexplored. Herein, we report the first systematic biological investigation of a diverse family of Au(I), Cu(I), Pt(II), Pd(II), and Ru(II) metallates paired with functionalized azolium cations. The complexes were synthesized quantitatively through a simple, atom-economical, and purification-free protocol under aerobic conditions in technical-grade green solvents. Structural characterization by multinuclear NMR spectroscopy and single-crystal X-ray diffraction confirmed metallate formation and enabled the first isolation and crystallographic characterization of unprecedented azolium-derived ruthenates. The antiproliferative activity of the complexes was evaluated against cisplatin-sensitive (A2780) and cisplatin-resistant (A2780cis) ovarian cancer cell lines, alongside non-cancerous MRC-5 fibroblasts. Backbone-functionalized derivatives emerged as the most potent compounds, displaying activities comparable or superior to cisplatin in A2780 cells and up to 1000-fold higher potency in the resistant A2780cis model. Notably, unlike cisplatin, the metallates retained nearly unchanged IC₅₀ values across both ovarian cancer lines, strongly suggesting resistance-evasive mechanisms of action. While benzylazido- and methyl guanosine-derived complexes generally exhibited lower overall potency, several members retained significant activity in resistant cells while showing markedly reduced toxicity toward normal fibroblasts, highlighting promising selectivity profiles. Ethoxide-functionalized derivatives and platinum-based metallates combined pronounced anticancer activity with favourable therapeutic windows. Overall, this work establishes azolium-derived metallates as a previously overlooked class of metal-based anticancer agents combining exceptional synthetic accessibility, broad structural tunability, and remarkable activity against platinum-resistant ovarian cancer. Full article

Silica dispersion in rubber matrices remains a critical issue due to the polarity mismatch between silica and the rubber phase. This study aimed to synthesize functionalized liquid polyisoprene rubber (F-LIR) and evaluate its role in improving the interfacial interaction between silica and solution styrene–butadiene rubber (SSBR). F-LIR was synthesized by introducing an alkoxysilane-containing functionalizing agent at the termination stage of anionic polymerization. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (¹H-NMR) were used to confirm the successful introduction of silyl groups at the chain ends of liquid polyisoprene. The optimal loading of F-LIR in SSBR was evaluated through bound rubber content, dynamic mechanical analysis, and mechanical performance testing. The results demonstrated that F-LIR improved the tensile strength, modulus at 300% elongation, and bound rubber content of SSBR composites. These enhancements are attributed to the reaction between the silyl groups of F-LIR and surface hydroxyl groups of silica, together with the co-crosslinking interaction between F-LIR and SSBR. The composites containing 4 phr F-LIR exhibited the best overall balance of properties. This study provides a novel method for synthesizing F-LIR, which bridges silica and the rubber matrix by enhanced filler–rubber interactions at the filler–rubber interface. Full article

The Saudi Arabian Red Sea has been a focus of ongoing scientific exploration due to its extensive, largely untapped marine biodiversity, particularly marine sponges. Marine sponges have long been recognised as a valuable source of unique compounds. In this study, we isolated a new brominated compound (1) from the marine sponge Aiolochroia crassa, collected from the Saudi Arabian Sea, using chromatographic analyses. Molecular networking analysis revealed the presence of brominated molecules in the extract. The identified compound belongs to a class of phosphatidylcholine derivatives. The structure of compound 1 was elucidated using 1D and 2D NMR spectroscopy and high-resolution ESI-Q-TOF mass spectrometry. Further structure confirmation studies were performed using MS/MS fragmentation analysis and DFT calculations for the ¹H and ¹³C NMR chemical shifts. This is the first report of 1 from this species of marine sponges. Full article

Cyathula officinalis Kuan, a medicinal plant used in traditional medicine, remains underexplored as a source of structurally defined wound-repair polysaccharides. In this study, a water-soluble polysaccharide fraction, CoPS, was isolated from C. officinalis roots and structurally characterized using methylation analysis and 1D/2D NMR spectroscopy. Purified CoPS had a total carbohydrate content of 94.8%, a weight-average molecular weight (M_w) of 7.491 kDa, and a narrow dispersity (M_w/M_n = 1.04). Monosaccharide composition analysis showed that CoPS was mainly composed of fructose and glucose at a molar ratio of 95.60:4.40. Structural analyses identified CoPS as a branched levan-type fructan with a β-(2→6)-linked fructofuranosyl backbone and β-(2→1)-linked branching motifs. CoPS was incorporated into a Carbomer/alginate topical formulation, termed CoPS-CPG, and evaluated in vitro and in vivo. CoPS-CPG showed good cytocompatibility and promoted HaCaT keratinocyte migration, reducing the residual scratch area to 48.10% at 12 h compared with 70.13% in the control group and 65.18% in the vehicle (Blank-CPG) group. In a murine full-thickness excisional wound model, CoPS-CPG reduced the residual wound area to 8.70 ± 1.20% on day 14, compared with 24.83 ± 1.51% in the control group and 14.20 ± 0.72% in the vehicle group. Histological and immunological analyses further indicated improved tissue reconstruction, a reduced inflammatory burden, enhanced CD206-associated macrophage signals, increased CD31-associated vascular structures, improved α-SMA-associated perivascular coverage, and lower late-stage HIF-1α expression. These findings identify CoPS as a structurally defined plant-derived levan-type fructan that supports cutaneous wound repair. Full article

We report a highly chemoselective N-sulfonylation of 3-(methylthio)-1H-1,2,4-triazol-5-amine with 4-nitrobenzenesulfonyl chloride promoted by N,N-diisopropylethylamine in acetonitrile under mild conditions. This transformation selectively affords N-(4-nitrophenyl)sulfonylation at the N1 position of the 1,2,4-triazole ring over the exocyclic amine functionality. The product was fully characterized by IR, 1D and 2D NMR spectroscopy, as well as high-resolution mass spectrometry, unequivocally confirming its molecular structure. Full article

A series of 1,2,3-triazole-linked-thiazolidine-2,4-dione hybrids (SDP1–SDP15) were designed, synthesized, and evaluated for their antidiabetic potential. All structures were characterized by FT-IR and NMR spectroscopy (¹H and ¹³C). All derivatives exhibited significant in vitro inhibition of α-glucosidase (IC₅₀: 24.17–46.41 µg/mL) and α-amylase (23.25–50.66 µg/mL), comparable to the standard drug acarbose (IC₅₀: 25.18 and 32.53 µg/mL) and superior to the reference drug pioglitazone (IC₅₀: 84.24 and 79.74 µg/mL) for α-glucosidase and α-amylase, respectively. Molecule SDP8 emerged as the most potent with an IC50 of 24.17 and 23.25 µg/mL for α-glucosidase and α-amylase, respectively. Further, SDP8 exhibited a higher docking score of −10.7 kcal/mol and −10.4 kcal/mol against α-glucosidase and α-amylase than pioglitazone (−8.1 kcal/mol and −7.7 kcal/mol, respectively), suggesting that interaction with these two enzymes may be the cause for its antidiabetic activity. Furthermore, DFT analysis revealed favorable electronic properties with a low HOMO-LUMO energy gap, whereas ADMET predictions revealed moderate drug-like characteristics with some limitations, such as poor solubility, relatively high lipophilicity, and partial noncompliance with drug-likeness regulations. Overall, these results highlight triazole-linked thiazolidinedione hybrids as promising candidates for further development in T2DM, with SDP8 serving as a preliminary lead requiring additional optimization and validation. Full article

The relationship between the position of the thiazole-5H proton signal and the presence of various substituents in the molecule was investigated in detail from an experimental and theoretical point of view. For this purpose, twenty 2,4-disubstituted thiazole derivatives were carefully chosen and synthesized, and their NMR spectra were recorded. Density functional theory calculations of ¹H NMR chemical shifts, frontier molecular orbitals, and molecular electrostatic potential surfaces were performed. The position of the thiazole-5H proton signal in the NMR spectrum is shown to strongly depend on the type and position of substituents in the molecule. Based on the obtained results, we can conclude that compounds with the smallest values of thiazole-5H proton shift are simultaneously those with small electron affinity, ionization potential and molecular electronegativity values, while compounds with the largest values of thiazole-5H proton shift have large electron affinity, ionization potential, and molecular electronegativity and a small HOMO-LUMO energy gap. These relationships become less clear in the case of compounds with intermediate values of the proton shift. Present research is a step towards an easy-to-use tool for predicting electronic effects in materials containing thiazole, based on the position of the thiazole-5H proton NMR signal. Full article

Penaeus sp. shells (shrimp) were used to extract chitosan using acid and basic treatments, which were characterized by IR spectroscopy, Raman spectroscopy, potentiometric titration, and elemental analysis. The degrees of deacetylation were determined to be 71.8%, 75.6%, 53.4%, and 68.6%, respectively. Likewise, viscosimetry measurements were carried out, determining an average molecular weight of chitosan 1 of 1521467.919 (g/mol). The obtained chitosan was used as a substrate in condensation reactions with 10 para-substituted benzaldehydes. The products obtained were characterized by IR, Raman, and ¹H-NMR spectroscopy, AE (Elemental Analysis), TGA (Thermogravimetric Analysis), and DSC (Differential Scanning Calorimetry). For the obtained polymers, biological assays of cytotoxicity using RAW macrophage cells and leishmanicidal activity on promastigotes of Leishmania mexicana were performed. The results show that the synthesized products do not present in vitro cytotoxicity, and that 1 (Chitosan) and 3i (Schiff Base) present leishmanicidal activity. Selected derivatives were incorporated into polyvinyl alcohol-based films and evaluated for surface topography and gas permeability. AFM revealed nanometric roughness patterns, while gas exchange studies demonstrated selective CO₂/O₂ permeability, supporting passive modified atmosphere formation in packaged carrots. Mechanical characterization revealed that the incorporation of Schiff base derivatives significantly influences tensile strength and flexibility, with certain films exhibiting enhanced elongation and mechanical performance compared to pure PVA, highlighting their potential for packaging applications. These findings confirm that chemical functionalization enhances the versatility of chitosan, allowing the design of tailored biopolymers. The synthesized derivatives show promising characteristics for the development of biodegradable films with potential applications in food packaging and antiparasitic material development. Full article

In this report, we describe the synthesis of two new celastrol derivatives featuring aryl-substituted 1,2,3-triazole fragments attached to the celastrol scaffold via an ester linkage. The target compounds, incorporating 4-methoxyphenyl and p-tert-butylphenyl groups, were characterized by ¹H and ¹³C NMR spectroscopy, FTIR, UV-Vis, HRMS, melting point determination, and specific rotation measurements. Full article

Three new heteroleptic copper(I) complexes of the form [Cu(N,N)(XantPhos)]PF₆ were synthesized and characterized, where N,N refers to phenyl-substituted imidazo[4,5-f][1,10]phenanthroline. All complexes were obtained as yellow powders in yields ranging 82–95% and were fully characterized by NMR spectroscopy, FT-IR, and mass spectrometry. The complexes were also redox-optically characterized. Their absorption profiles display a lower-energy metal-to-ligand charge-transfer (MLCT) band at approximately 412 nm. In solution, weak dual emission is observed, combining ligand-centered and MLCT contributions, with oxygen-dependent quenching supporting the presence of triplet character in the latter. Temperature- and solvent-dependent studies reveal thermally coupled emissive states, in which a relaxed ³MLCT state dominates at low temperatures. In the solid state, intense orange-to-red emission arises from restricted molecular motion and stabilized ³MLCT states, with C3 showing the highest efficiency. Additionally, aggregation-induced emission (AIE) is observed in solvent mixtures. These results suggest that remote substitution can influence the excited-state dynamics and aggregation-driven emission in Cu(I) complexes. Full article