Investigation of the vesicle-to-micelle transition of 11-amino undecanoic acid derived sulphonamide and a comprehensive study of its interaction with protein.

In the present manuscript, an amphiphile sulphonamide based surfactant benzenesulphonyl-11-amino sodium undecanoate (BASU) is designed and synthesized. The surface activity of the amphiphile in the solutions is studied at neutral pH so that the resulting amphiphile self-organizes and transfers from large unilamellar vesicles to small micelles from dilute to concentrated solutions. During the aggregate transitions, the common surfactants tend to form the small aggregate at low concentrations; but BASU shows the large vesicle structure at low concentration of ~3 mM and converts into the small micelle at ~9 mM. Therefore, different techniques have been used, such as, tensiometry, conductometry, fluorimetry and DLS and some microscopic characterization, e.g., confocal fluorescence microscopy to reveal the aggregate assembly and transition mechanism. The isothermal titration calorimetry is used for quantitative measurement of thermodynamic properties of self-assembly formation and the process is found spontaneous and entropically favorable. The permeability of the vesicle membrane bilayer is explored by a kinetic study. Effects of salt and cholesterol on the aggregate of respective amphiphile are also investigated. The interaction of surfactant with both human and bovine serum albumin is analyzed through UV-visible and fluorescence techniques to draw a comparative study. Antibacterial activity is tested by both spectral and zone inhibition methods and its application for mixed amphiphiles (e.g., BASU/CTAB) is found. Therefore, according to the ability of formation of unilamellar vesicles (ULV) and its stability, permeability and antibacterial activity, the amphiphile can have potential applications in the medicinal field.

Interaction between a Nonsteroidal Anti-inflammatory Drug (Ibuprofen) and an Anionic Surfactant (AOT) and Effects of Salt (NaI) and Hydrotrope (4-4-4).

Ibuprofen (IBF), 2-(4-isobutylphenyl) propionic acid, is a surface-active, common nonsteroidal anti-inflammatory drug (NSAID), and it possesses a high critical micelle concentration (cmc) compared to that of conventional surfactants. The interactions of this common NSAID with an anionic surfactant, sodium octyl sulfosuccinate, were studied by tensiometric, fluorimetric, and calorimetric measurements to investigate this system as a possible model drug-delivery system for an NSAID like IBF, particularly in a high-dose regime for IBF. The interactions between the drug and the surfactant were modeled using a regular solution theory approach in the presence and absence of a model electrolyte (sodium iodide) and a novel nonaromatic, gemini hydrotrope, tetramethylene-1,4-bis( N, N-dimethyl- N-butylammonium)bromide (4-4-4). Both the simple and the hydrotropic electrolyte were shown to have an effect on the solution properties (aggregation parameters, interfacial properties, and thermodynamics of aggregate formation) of the drug-surfactant mixtures and on the interaction between the drug and the surfactant. Surface charges of all self-assembled systems were estimated from ζ-potential measurements, whereas density functional theory calculations showed the interaction energy comparison among all of the binary and ternary combinations. All of these results were interpreted in terms of how altering the subtle balance of hydrophobic and electrostatic forces can significantly improve the ability of these self-assembled systems to transport drug molecules.