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Separation of Surfactant Micelle-Organic Pollutant Complex Using A High-Shear Rotary Ultrafiltration System
Published in Gregory D. Boardman, Hazardous and Industrial Wastes, 2022
Wei Lin, Brian E. Reed, Henyi Xue
Surfactants, or surface active agents, are substances that have amphiphilic molecules which have both hydrophilic groups and a hydrophobic paraffin chain. When dissolved in water, the amphiphilic surfactant molecules have a tendency to collect at any interface where the hydrophobic groups can be partially or completely removed from the contact of water and the hydrophilic groups can remain wetted. The same dual tendencies of the surfactant molecules will cause the formation of particles of colloidal dimensions which are termed micelles when the surfactant concentration is in excess of a certain value. In micelle formation, the molecules undergo self-association in solution to produce aggregates in which the hydrocarbon chains are put together so that the total contact area of the hydrophobic groups of the surfactant molecules with water is reduced [1]. The concentration at which micelles form is termed the critical micelle concentration (CMC).
Nanotechnological Advances for Nutraceutical Delivery
Published in Rakesh K. Sindhu, Mansi Chitkara, Inderjeet Singh Sandhu, Nanotechnology, 2021
Shaveta Sharma, Puneet Sudan, Vimal Arora, Manish Goswami, Parkash Dora
Micelles are widely used to deliver nutraceuticals and have a core– shell characteristic structure in which the hydrophilic head region supports and stabilizes the hydrophobic core in the aqueous medium and increases water solubility, and the hydrophobic region carries and protects the drug. They efficiently improve the efficacy of therapeutic drugs associated with CNS diseases [24]. Micelles are formed above the critical micelle concentration (CMC) and are thermodynamically stable [14]. Beyond the CMC, individual amphiphiles immediately form micelles. Limitations among micelles are low drug-loading efficiency and low serum stability; even they are good nanocarriers for lipophilic bioactives [25]. Bioactives incorporated in micellar nanoformulation show low serum stability mainly when diluted with blood (below CMC) after systemic injection.
Self-assembly of Amphiphilic Molecules
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2019
Domenico Lombardo, Maria Teresa Caccamo, Pietro Calandra
Amphiphiles are (macro-) molecules possessing a water-loving (hydrophilic) component attached to a water-hating (hydrophobic) or a fat-loving (lipophilic) component. In conventional head/tail(s) amphiphiles, the hydrophilic head can be either nonionic or ionic, while the hydrophobic part consists generally of a long hydrocarbon chain. Due to their ability to reduce the interfacial tension, the amphiphilic molecules are often called surfactants (i.e., surface active agents). In aqueous solutions, the amphiphile (hydrophilic) polar headgroup interacts with the water, while the nonpolar (hydrophobic or lipophilic) chain will migrate above the interface (either in the air or in a nonpolar region of the liquid) [5]. In this case, the disruption of the cohesive energy at the interface favors a microphase separation between the selective solvent and the dispersed phase of the amphiphile with the formation of many smaller closed interfaces of micelles-like aggregates [6]. Due to this characteristic, many amphiphiles are employed as detergents, emulsifiers, dispersants, wetting and foaming agents in several applications [7].
Phase separation and thermodynamics of the mixture of metformin hydrochloride + triton X-100 in ammonium salts media: impacts of composition of media
Published in Molecular Physics, 2022
Tajmul Hasan, Shamim Mahbub, Dileep Kumar, Mansour K. Gatasheh, Md. Tuhinur R. Joy, Md. Abdul Goni, Shahed Rana, Md. Anamul Hoque
Surfactants are amphiphilic compounds whose molecular structures are endowed with both lipophilic and hydrophilic moieties. The lipophilic portions of molecules of the surfactant’s compounds are soluble in organic media and are highly hydrophobic, while the hydrophilic ends are predominantly soluble in water. Because of having this dual behaviour, surfactants are often referred to as amphiphiles. The surfactants compounds exhibit the remarkable properties of forming micelles, and the method of forming this micelle species is defined as micellisation. The term ‘critical micelle concentration’ (cmc) describes the concentration of surfactants over which micelle production occurs [1–4]. The extent of cmc varies with the addition of electrolytes, additives, hydrotropic compounds, changes in temperatures, surfactants and compositions of mixed solvents [1–8]. A very special group of surfactants that do not contain charged groups are referred to as non-ionic surfactants. These non-ionic surfactants have drawn significant attention in recent years for their wide applications in different fields such as wetting, cleaning, foaming processes, drug carrier systems, textiles, detergents, cosmetic industries and in various pharmaceutical formulations [9–19].
Significant biopolymers and their applications in buccal mediated drug delivery
Published in Journal of Biomaterials Science, Polymer Edition, 2021
It is a major milk component protein and edible material which is suitable as a drug carrier via the oral delivery route. β-Casein has the property to self-assemble and form micelle-like structures by intermolecular hydrophobic interaction. It is amphiphilic and its self-micelle forming ability makes it a suitable component for drug delivery. 15-60 β-Casein molecule forms a micelle, having a size of 7-14 nm. The size of this micelle can also be changed by changing the temperature, pH, hydrostatic pressure, ionic strength, water activity, etc. For using β-casein for drug delivery, it is necessary to stabilize it, which is generally achieved by crosslinking lysine residue of casein to glutamic residue of transglutaminase and some other methods can also be employed. Many hydrophobic drugs are entrapped within β-casein for target activated release of drug by the oral delivery system. Some of the examples of drugs used for this purpose are mitoxantrone, vinblastine, irinotecan, docetaxel, etc [19].
Cosolvent effect on the dynamics of water in aqueous binary mixtures
Published in Molecular Physics, 2018
Xia Zhang, Lu Zhang, Tan Jin, Qiang Zhang, Wei Zhuang
Binary aqueous mixture as versatile solvent and medium is widely used in the life science, energy, chemical engineering as well as environmental fields [1–6]. Adding solute molecules into water often leads to non-trivial variation of the physical and chemical properties [7–24], which are closely related to the structures and the dynamics of hydrogen bond network. For the aqueous mixture of amphiphilic molecules, an intriguing observation is that many physical properties can vary non-monotonically with similar extrema as the amphiphilic molecule's molar fraction changes from 0 to 1 [7–24]. This deviates from the Raoult's law for the ideal mixtures [8]. Amphiphilic molecules have both hydrophilic and hydrophobic moieties at the same time; therefore, they have two opposite influences on water. The hydrophilic group forms hydrogen bonds with water, while the hydrophobic group may lead to micro-segregation by a hydrophobic hydration effect. Due to the complexity of the highly disordered structure and dynamics in these mixtures, many aspects of the non-idealities remain elusive.