Thermodynamic Characterization of the Interaction between the Antimicrobial Drug Sulfamethazine and Two Selected Cyclodextrins

New Insights into pH-dependent Complex Formation between Lignosulfonates and Anthocyanins: Impact on Color and Oxidative Stability

Anthocyanins have limited application as natural colorants and antioxidants due to their color loss and instability under certain conditions. This research explores the formation of a complex between lignosulfonates (LS) and cyanidin-3-O-glucoside (C3G) using a multitechnique approach as well as the effect on C3G's red color, oxidative stability, and antioxidant activity in acidic mediums. All data revealed pH-dependent LS-C3G interactions. The thermodynamic parameters showed weak noncovalent interactions, mainly electrostatic interactions, hydrogen bonds, and hydrophobic effect, with a higher association constant determined at pH 3. Fourier-transform infrared spectroscopy and Zeta-potential experiments further corroborate evidence of these LS-C3G interactions. Fluorescence quenching and lifetime experiments revealed static and dynamic quenching at pH 1 and 3, respectively. UV-visible spectroscopy demonstrated a bathochromic shift upon complex formation and a hyperchromic effect at pH 3 and 4, as a consequence of the improved red color of C3G. Electrochemical results suggested that at pH 3 the LS enhances C3G stability by protecting its oxidizable moieties over time, as well as improving the antioxidant activity of the anthocyanin in the complex.

On Interactions of Sulfamerazine with Cyclodextrins from Coupled Diffusometry and Toxicity Tests

This scientific study employs the Taylor dispersion technique for diffusion measurements to investigate the interaction between sulfamerazine (NaSMR) and macromolecular cyclodextrins (β-CD and HP-β-CD). The results reveal that the presence of β-CD influences the diffusion of the solution component, NaSMR, indicating a counterflow of this drug due to solute interaction. However, diffusion data indicate no inclusion of NaSMR within the sterically hindered HP-β-CD cavity. Additionally, toxicity tests were conducted, including pollen germination (Actinidia deliciosa) and growth curve assays in BY-2 cells. The pollen germination tests demonstrate a reduction in sulfamerazine toxicity, suggesting potential applications for this antimicrobial agent with diminished adverse effects. This comprehensive investigation contributes to a deeper understanding of sulfamerazine-cyclodextrin interactions and their implications for pharmaceutical and biological systems.

The Effect of Alkali Iodide Salts in the Inclusion Process of Phenolphthalein in β-Cyclodextrin: A Spectroscopic and Theoretical Study

The formation of the inclusion complex between β-cyclodextrin (CD) and phenolphthalein (PP) was investigated by means of UV-Vis and FT-IR spectroscopies. The thermodynamic parameters were calculated in the absence and presence of LiI, KI, NaI and CsI iodide salts. The enthalpy change during the formation was found to be negative for all solutions with iodide salts. The enthalpy change was found to decrease in the sequence no salt > NaI > KI> CsI > LiI. Moreover, it was observed that with increasing salt concentration enthalpy decreases monotonically. The interaction between the two molecules was mostly attributed to hydrogen bonding and Van der Waals interactions. Thermodynamic properties revealed that electrostatic forces also contribute when LiI is present in solutions. A molecular docking study was performed to elucidate the docking between phenolphthalein and cyclodextrin. The FT-IR spectra of CD, PP and the CD-PP complex were recorded to establish the formation of the inclusion complex. Semi-empirical and DFT methods were utilized to study theoretically the complexation process and calculate the IR vibrational spectra. The adequate agreement between theoretical and experimental results supports the proposed structural model for the CD-PP complexation.

Temperature-Induced Change of Water Structure in Aqueous Solutions of Some Kosmotropic and Chaotropic Salts

The hydrogen bond structure of water was examined by comparing the temperature dependent OH-stretching bands of water and aqueous NaClO₄, KClO₄, Na₂SO₄, and K₂SO₄ solutions. Results called attention to the role of cations on top of the importance of anions determining the emerging structure of a multi-layered system consisting single water rings or multi-ring water-clusters.

Sulfonamide drugs: structure, antibacterial property, toxicity, and biophysical interactions

Sulfonamide (or sulphonamide) functional group chemistry (SN) forms the basis of several groups of drug. In vivo sulfonamides exhibit a range of pharmacological activities, such as anti-carbonic anhydrase and anti-t dihydropteroate synthetase allowing them to play a role in treating a diverse range of disease states such as diuresis, hypoglycemia, thyroiditis, inflammation, and glaucoma. Sulfamethazine (SMZ) is a commonly used sulphonamide drug in veterinary medicine that acts as an antibacterial compound to treat livestock diseases such as gastrointestinal and respiratory tract infections. Sulfadiazine (SDZ) is another frequently employed sulphonamide drug that is used in combination with the anti-malarial drug pyrimethamine to treat toxoplasmosis in warm-blooded animals. This study explores the research findings and the work behaviours of SN (SMZ and SDZ) drugs. The areas covered include SN drug structure, SN drug antibacterial activity, SN drug toxicity, and SN environmental toxicity.

The Role of β-Cyclodextrin in the Textile Industry-Review

β-Cyclodextrin (β-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk conical shape organization, with a well-defined cavity, provides an adequate environment for several types of molecules to be included. Complexation changes the properties of the guest molecules and can increase their stability and bioavailability, protecting against degradation, and reducing their volatility. Thanks to its versatility, biocompatibility, and biodegradability, β-CD is widespread in many research and industrial applications. In this review, we summarize the role of β-CD and its derivatives in the textile industry. First, we present some general physicochemical characteristics, followed by its application in the areas of dyeing, finishing, and wastewater treatment. The review covers the role of β-CD as an auxiliary agent in dyeing, and as a matrix for dye adsorption until chemical modifications are applied as a finishing agent. Finally, new perspectives about its use in textiles, such as in smart materials for microbial control, are presented.

Adsorption of Sulfamethazine Drug onto the Modified Derivatives of Carbon Nanotubes at Different pH

The sulfamethazine drug interaction with carbon nanotubes was investigated with the aim of improving the adsorption capacity of the adsorptive materials. Experiments were performed to clarify how the molecular environment affects the adsorption process. Single-walled carbon nanotubes have a higher removal efficiency of sulfamethazine than pristine or functionalized multi-walled carbon nanotubes. Although the presence of cyclodextrin molecules improves the solubility of sulfamethazine, it reduces the adsorption capacity of the carbon nanotube towards the sulfamethazine drug and, therefore, inhibits the removal of these antibiotic pollutants from waters by carbon nanotubes.

Applying Different Techniques to Improve the Bioavailability of Candesartan Cilexetil Antihypertensive Drug

Purpose

The objective of this study was to compare different techniques to enhance the solubility and dissolution rate, and hence the bioavailability of candesartan cilexetil.

Methods

To achieve this target, various techniques were employed such as solid dispersions, inclusion complexes, and preparation of candesartan nanoparticles. Following the preparations, all samples were characterized for their physicochemical properties, and the samples of the best results were subjected to further bioavailability studies.

Results

Results of dissolution studies revealed an increase in the dissolution rate of all samples. The highest dissolution rate was achieved using solid dispersion of the drug with PVP K-90 (1:4). Physicochemical investigations (XR, DSC, and FT-IR) suggested formation of hydrogen bonding and changing in the crystalline structure of the drug. Regarding the inclusion complexes, more stable complex was formed between HP-β-CD and CC compared to β-CD, as indicated by phase solubility diagrams. Antisolvent method resulted in the preparation of stable nanoparticles, as indicated by ζ potential, with average particle size of 238.9 ± 19.25 nm using PVP K-90 as a hydrophilic polymer. The best sample that gave the highest dissolution rate (CC/PVP K-90 1:4) was allowed for further pharmacokinetic studies using UPLC MS/MS assay of rabbit plasma. Results showed a significant increase in the bioavailability of CC from ~15% to ~48%.

Conclusion

The bioavailability of CC was significantly improved from ~15% to ~48% when formulated as SDs with PVP K-90 with 1:4 drug:polymer ratio.