Influence of ammonium salts on the interaction of fluoroquinolone antibiotic drug with sodium dodecyl sulfate at different temperatures and compositions

Interaction between gastric enzyme pepsin and tetradecyltrimethylammonium bromide in presence of sodium electrolytes: Exploration of micellization behavior

Pepsin is a proteolytic enzyme used in the treatment of digestive disorders. In this study, we investigated the physicochemical properties of the tetradecyltrimethylammonium bromide (TTAB) and pepsin protein mixture in various sodium salt media within a temperature range of 300.55-320.55 K with 5 K intervals. The conductometric study of the TTAB+pepsin mixture revealed a reduction in the critical micelle concentration (CMC) in electrolyte media. The micellization of TTAB was delayed in the presence of pepsin. The CMC of the TTAB + pepsin mixture was found to depend on the concentrations of electrolytes and protein, as well as the temperature variations. The aggregation of the TTAB+pepsin mixture was hindered as a function of [pepsin] and increasing temperatures, while micellization was promoted in aqueous electrolyte solutions. The negative free energy changes (∆Gm0) indicated the spontaneous aggregation of the TTAB+pepsin mixture. Changes in enthalpy, entropy, molar heat capacities, transfer properties, and enthalpy-entropy compensation variables were calculated and illustrated rationally. The interaction forces between TTAB and pepsin protein in the experimental solvents were primarily hydrophobic and electrostatic (ion-dipole) in nature. An analysis of molecular docking revealed hydrophobic interactions as the main stabilizing forces in the TTAB-pepsin complex.

Aggregation phenomena and physico-chemical properties of tetradecyltrimethylammonium bromide and protein (bovine serum albumin) mixture: Influence of electrolytes and temperature

It is important for biological, pharmaceutical, and cosmetic industries to understand how proteins and surfactants interact. Herein, the interaction of bovine serum albumin (BSA) with tetradecyltrimethylammonium bromide (TTAB) in different inorganic salts (KCl, K2SO4, K3PO4.H2O) has been explored through the conductivity measurement method at different temperatures (300.55 to 325.55 K) with a specific salt concentration and at a fixed temperature (310.55 K) using different salts concentrations. The extent of micelle ionization (α) and different thermodynamic parameters associated with BSA and TTAB mixtures in salt solutions were calculated. Evaluation of the magnitudes of ∆Hm0 and ∆Sm0 showed that the association was exothermic and primarily an enthalpy-operated process in all cases at lower contents of BSA, but the system became endothermic, and entropy driven in the presence of K3PO4.H2O at a relatively higher concentration of BSA. The enthalpy-entropy compensation variables were determined, which explained the types and nature of interactions between TTAB and BSA in salt media. Molecular docking analysis revealed that the main stabilizing factors in the BSA-TTAB complex are electrostatic and hydrophobic interactions. These findings aligned with the significant results obtained from the conductometry method regarding the nature and characteristics of binding forces observed between BSA and TTAB.

Formation and Phase Transformation of MgCO3·3H2O Whiskers in the Presence of Sodium Dodecyl Sulfate

Huge amounts of MgCl₂·6H₂O are produced annually as a byproduct or waste from KCl production in the Qinghai province of China. An ecological and economic way to solve this problem is transforming the abandoned MgCl₂·6H₂O to valuable MgCO₃·3H₂O whiskers. The formation and phase transformation of MgCO₃·3H₂O whiskers were studied in the crystallization process, in which MgCl₂ and NH₄HCO₃ were precipitated in the presence of sodium dodecyl sulfate (SDS) at 50 °C. Results showed that porous spherical MgCO₃·3H₂O, MgCO₃·3H₂O whiskers, and flocculent rod-like 4MgCO₃·Mg(OH)₂·4H₂O were formed with decreasing concentration of SDS as the crystallization proceeded. When the concentration of SDS was lower than the critical micellar concentration (6.5 mmol·L^-1) at 60 min, SDS was beneficial for the growth in the [010] direction to form one-dimensional MgCO₃·3H₂O whiskers with a high aspect ratio, good uniformity, and a smooth surface (length, 60-70 μm; aspect ratio, 110-140).

Influences of NaCl and Na2SO4 on the Micellization Behavior of the Mixture of Cetylpyridinium Chloride + Polyvinyl Pyrrolidone at Several Temperatures

Herein, the conductivity measurement technique is used to determine the interactions that may occur between polyvinyl pyrrolidone (PVP) polymer and cetylpyridinium chloride (CPC) surfactant in the presence of NaCl and Na2SO4 of fixed concentration at variable temperatures (298.15-323.15 K) with an interval of 5 K. In the absence or presence of salts, we observed three critical micelle concentrations (CMC) for the CPC + PVP mixture. In all situations, CMC1 values of CPC + PVP system were found to be higher in water than in attendance of salts (NaCl and Na2SO4). Temperature and additives have the tendency to affect counterion binding values. Various physico-chemical parameters were analyzed and demonstrated smoothly, including free energy (ΔG0m), enthalpy (ΔH0m) and entropy change (ΔS0m). The micellization process is achieved to be spontaneous based on the obtained negative ΔG0m values. The linearity of the ΔHmo and ΔSmo values is excellent. The intrinsic enthalpy gain (ΔH0*m) and compensation temperature (Tc) were calculated and discussed with logical points. Interactions of polymer hydrophobic chains or the polymer + surfactant associated with amphiphilic surface-active drugs can employ a strong impact on the behavior of the gels.

Aggregation behavior and thermodynamic properties of the mixture of sodium carboxymethyl cellulose and cetyltrimethylammonium bromide in numerous temperatures and mixed solvents

Interaction of sodium carboxymethylcellulose (SCMC) with cetyltrimethylammonium bromide (CTAB; cationic in nature) in H2O and additives (alcohols and diols) media has been investigated using conductivity technique. The micellar parameters such as critical micelle concentration (cmc), fraction of counter ion binding (β), thermodynamic parameters, transfer properties, and enthalpy-entropy compensation parameters of CTAB + SCMC mixture have been assessed in water and aq. alcohols/diols media. One cmc value was achieved for CTAB + SCMC mixtures in the entire circumstances and the attendance of SCMC disfavors the CTAB micellization. The cmc values were obtained to be greater in alcohols and diols media compared to H2O medium. The cmc values also exhibit a dependency on the solvent composition and temperature variation. In all the cases, the ΔG 0 m values were achieved to be negative which signifying the spontaneous formation of micelles while the extent of spontaneity is decreased in alcohols and diols media. Both the ΔH 0 m and ΔS 0 m reveal that hydrophobic, ion-dipole as well as electrostatic interactions are the proposed binding forces between CTAB and SCMC. The compensation parameters (ΔH 0* m and T c ) are in decent agreement with the biological fluid.

Synthesis, Characterization, and Evaluation of Solution Properties of Sesame Fatty Methyl Ester Sulfonate Surfactant

The search for alternative, biodegradable, and sustainable raw materials to replace finite petrochemicals is an area of great interest. Triglycerides obtained from oilseed crops are such potential raw materials. In this study, sesame oil was trans-esterified to sesame fatty methyl esters (SEFAMEs) that were used as precursors in the synthesis of sesame fatty methyl esters sulfonate (SEFAMESO) surfactant. SEFAME and SEFAMESO surfactants were characterized by high-performance liquid chromatography-mass spectrometry (HPLC-MS), 1H NMR, and Fourier transform infrared (FTIR) spectra. HPLC-MS, 1H NMR, and FTIR spectra indicated successful trans-esterification and conversion of SEFAMEs to SEFAMESO. Solution properties of the SEFAMESO surfactant including hydrophilic-lipophilic balance (HLB) value, Krafft point, foam-ability, critical micelle concentration (CMC), counterion degree of binding and thermodynamic parameters such as ΔG°mic, ΔH°mic, ΔS°mic, ΔH°mic,* and T C were evaluated. The CMC values of SEFAMESO at 298.15 K were relatively lower than that of the sodium dodecyl sulfate (SDS) standard, and these values decreased to a minimum at 303.15 K and then increased with an increase in temperature. ΔG°mic values were negative indicating a spontaneous micellization process. ΔH°mic and ΔS°mic values revealed that micellization was entropy-driven at low temperatures and both entropy- and enthalpy-driven at high temperatures. ΔH°mic,* values were negative suggesting formation of stable micelles. The evaluated properties revealed the potential application of the synthesized surfactant as a cleansing agent.