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Volumetric, acoustic and molecular docking investigations are helpful to elucidate the molecular interactions occurring between saccharides/derivatives with cefadroxil drug in aqueous solution. The density, ρ and speed of sound, u were measured for saccharides and their derivatives, in molality, mB = (0.001–0.004) mol∙kg−1 aqueous solutions of cefadroxil at temperatures, T = (288.15, 298.15, 308.15, 318.15) K. These values were used to retrieve the corresponding values of standard partial molar volumes, V2° and partial molar isentropic compressibilties, K°s,2 at infinite-dilution. From these data, the transfer properties (ΔtrV2° and ΔtrK°s,2) for saccharides from water to aqueous solutions of cefadroxil have been evaluated. These parameters provide an essence about the type and nature of interactions occurring between saccharide (solute) and cefadroxil drug. Further, the molecular docking studies have also been carried out, which give information about the active groups present in both solutes and cefadroxil molecules at the binding site. Both the experimental and theoretical studies show that the distinct stereochemical –OH group present in the studied saccharides/derivatives interact differently with the cefadroxil molecule. The theoretical studies also show that the –NH, –NH2, >C O and –COOH groups of cefadroxil participate more actively at the binding site.

Enthalpy change, q of polyhydroxy solutes; (+)- d -xylose, xylitol, (−)- l -sorbose, d -sorbitol, (+)- d -glucose, and (+)- d -maltose monohydrate have been measured in water and in aqueous (0.10, 0.15, 0.25, and 0.35) mol·kg− 1 ammonium bromide (NH4Br) and (0.15, 0.25, and 0.35) mol·kg− 1 tetraethylammonium bromide (Et4NBr) solutions at T = (288.15, 298.15, 308.15, and 318.15) K by using isothermal titration microcalorimeter. From the data q, the limiting standard enthalpies of dilution (ΔdilH°) and their corresponding transfer parameters (ΔtΔdilH°) have been evaluated. The enthalpic interaction coefficients that characterize the interactions of polyhydroxy solutes with ammonium salts in aqueous solutions were determined from ΔtΔdilH° values. Proton (1H) NMR spectra were recorded for mB = (0.15, 0.25 and 0.35) mol·kg− 1 tetraethylammonium bromide solutions and in ternary solutions {polyhydroxy solute + Et4NBr + 9:1 (w/w) H2O + D2O}, where the molality of solute has been fixed as mA = 0.25 mol·kg− 1. The comparison of NMR results shows more upfield shift in ternary solutions than in pure alkyl ammonium salt solution, thereby suggesting the predominance of hydrophobic-ionic interactions over hydrophilic-ionic interactions.

To investigate the molecular interactions of polyhydroxy solutes with cetyltrimethylammonium bromide (CTAB) surfactant, we have measured the densities and viscosities of (+)- d -xylose, xylitol, (−)- l -sorbose, d -sorbitol, (+)- d -glucose, and (+)- d -maltose in (4.0, 8.0, and 12.0) · 10−4 mol·kg−1 CTAB(aq) solutions at (298.15, 308.15 and 318.15) K. The density data have been utilized to evaluate apparent molar volumes (V2,ϕ), partial molar volumes (V2°) and their transfer (ΔtV2°) values at infinite-dilution. The viscosity data were analyzed using the Jones-Dole equation and further used to calculate the viscosity B-coefficients and transfer B-coefficients, ΔtB. The structure-making/-breaking behavior of the polyhydroxy solutes were analyzed using the signs and magnitude of (∂2V2°/∂T2)P and dB/dT coefficients. It has been observed that the positive ΔtV2° and ΔtB values increase with increasing CTAB concentration. 1H NMR spectroscopic study of polyhydroxy solutes was also carried out in mB = (4.0, 8.0, and 12.0) · 10−4 mol·kg−1 CTAB solutions which were made in 9:1 (w/w) H2O + D2O solvent. NMR results showed higher downfield shift in ternary (polyhydroxy solute + CTAB + 9:1 (w/w) H2O + D2O) solutions as compared to pure CTAB solution, hence suggested the predominance of hydrophilic-ionic interactions over hydrophobic-ionic interactions.

The physicochemical studies are significant in understanding the molecular interactions of saccharides and their derivatives with amoxicillin drug in aqueous solution. Therefore, the apparent molar volumes (V2,ϕ), and the limiting standard molar enthalpies of dilution (ΔdilH∞m) of saccharides and their derivatives in (0.001, 0.002, 0.003 and 0.004) mol·kg–1 aqueous solutions of amoxicillin were determined from the precise density, ρ and heat change, q measurements at (288.15, 298.15, 308.15 and 318.15) K under pressure, p = 0.1 MPa. The data were processed to obtain the corresponding transfer volumes (ΔtrV2∞) and enthalpies of dilution of transfer (ΔtΔdilH∞m) of solutes from water into aqueous solutions of amoxicillin. The volumetric expansion coefficients (∂V2∞/∂T)P, their second-order derivatives (∂2V2∞/∂T2)P and heat capacity change (∆dilC∞p,2,m) were also determined. Proton (1H) NMR spectra for mA = 0.02 mol·kg–1 saccharides/derivatives were also recorded in different molalities, mB = 0.001, 0.002, 0.003 and 0.004 mol·kg–1 of amoxicillin solution prepared in solvent {9:1 H2O + D2O}. The NMR results show that the Hc proton of amoxicillin has more activity (acidity) and it interacts more with the solute molecules (saccharide/derivative) than other protons of amoxicillin.

Owing to the internal cavity of cyclodextrins, they are very notable to form the inclusion complexes with various drugs. In present work, the binding of trimethoprim (TMP) drug with native α-, β-, and γ-cyclodextrins (CDs) were systematically examined using the isothermal titration calorimetry (ITC), spectroscopic {UV–visible, nuclear magnetic resonance (NMR)} methods, dynamic light scattering (DLS) and molecular modeling of the complex formed by host (cyclodextrins) and guest (trimethoprim) molecules. The stability of the TMP-CDs inclusion complexes increases in the following order: α-CD

Micellization behaviour of cationic surfactant; cetyltrimethylammonium bromide (CTAB) has been studied in water and in aqueous solutions of polyhydroxy compounds (PHC) as solvents at (298.15, 308.15 and 318.15) K using specific conductance and isothermal titration calorimetric (ITC) measurements. From the specific conductance (κ), various parameters such as critical micelle concentration (CMC), degree of ionization of micelle (β), standard Gibbs free energy (ΔGom), enthalpy (ΔHom), and entropy (ΔSom) of micellization have also been calculated. The CMC values of CTAB increase with rise of temperature and decrease linearly with increase in the concentration of PHC. The ITC measurements provide additional insights into the various thermodynamic parameters associated with the micellization process. The results from both techniques have been used to study the influence of PHC on the micellization behaviour of the surfactant.

Densities, ρ, speed of sound, u , for aqueous solutions of alkoxyalkanols like ethylene glycol mono methyl ether (EGMME), ethylene glycol mono ethyl ether (EGMEE) and ethylene glycol mono butyl ether (EGMBE) have been measured in aqueous solutions of surfactant sodium dodecyl sulphate (SDS) at temperatures T = (288.15, 298.15, 308.15 and 318.15) K have been measured. The different parameters such as apparent molar volume, limiting apparent molar volume, transfer volume, partial molar expansibility have been derived from density data to study the nature of interactions and also the aggregation behavior of surfactant with alkoxyalkanols. Experimental speeds of sound data were used to estimate apparent molar isentropic compression, limiting apparent molar isentropic compression, partial molar isentropic compression of transfer. The pair and triplet interaction coefficient have been calculated from both the properties. These parameters have been discussed in the light of ion-ion and ion-solvent interactions.