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Electrolyte solutions
Published in W. John Rankin, Chemical Thermodynamics, 2019
Water dissolves many salts, hydrophilic organic molecules, such as sugars and simple alcohols, and most acids. The two hydrogen atoms in the water molecule are bonded to the oxygen atom at an angle of 104.45°, and water thus behaves as a polar compound − each molecule is an electric dipole. This results in relatively weak bonding between the molecules (hydrogen bonds) in which the hydrogen atoms function as a bridge between adjacent oxygen atoms. When certain types of solid substances are added to water, the hydrogen bonds are disrupted at the solid−liquid interface thereby releasing water dipoles. These are attracted to the points of charge on the solid and, if these attractions are sufficiently large to overcome the inter−ionic attractions in the solid, the substance dissolves to form ions in solution. These ions are then surrounded by water molecules which form a relatively ordered structure close to the ion, called the inner co-ordination sphere. This structure progressively becomes less ordered towards the bulk of the solvent. The resulting solution remains electrically neutral as the sum of charges on cations is balanced by those on anions.
Pharmaceutical Applications of Gelatin
Published in Amit Kumar Nayak, Md Saquib Hasnain, Dilipkumar Pal, Natural Polymers for Pharmaceutical Applications, 2019
Vishal Girdhar, Shalini Patil, Sunil Kumar Dubey, Gautam Singhvi
Liposomes are small bilayered spherical systems comprising phospholipids which has an aqueous core. These have been successfully used for the delivery of both the hydrophilic as well as the hydrophobic drug. It is one of the most advanced delivery systems because of its many advantages like high biocompatibility with the active molecule and its ability to target the site of action. Because of the use of phospholipids in the liposomes, a hydrophilic core is created and the bilayer formed is hydrophobic in nature which is why liposomes have been used for the entrapment of both the hydrophilic as well as the hydrophobic drugs.
Giant Micelles and Shampoos
Published in Raoul Zana, Eric W. Kaler, Giant Micelles, 2007
Most hydrophilic surfactants are endowed with the property of shifting from molecular solution to spherical micelles then to elongated (wormlike) micelles before reaching the domain of mesomorphic phases (hexagonal, lamellar, etc.) as their concentration is increased.
Synthesis of salt-resistant hyperbranched waterborne polyurethane associative thickener and its application in textile printing
Published in The Journal of The Textile Institute, 2023
Polyurethane thickener is a non-ionic associative thickener which emerged after APAT (Suzuki et al., 2012). Unlike APAT, polyurethane thickener is composed of hydrophilic segments, hydrophobic segments and urethanes as linking groups, forming a ‘hydrophobic-hydrophilic-hydrophobic’ linear molecular structure (Barmar et al., 2005). In aqueous solution, the hydrophobic segments associate with several other ones to form micellar cores, and the hydrophilic segments come into being the flower loops. Thereby the flower-like micelles are formed (Peng et al., 2014). At the same time, the hydrophilic segments act as bridges among the micelles (Peng et al., 2014). Furthermore, the hydrophilic segments can form hydrogen bonds with the surrounding water molecules and restrict the movement of water molecules, thereby increasing the viscosity of the aqueous solution (Peng et al., 2014). The polyurethane thickener is non-ionic and its thickening effect is hardly affected by the salt. In addition, polyurethane thickener possesses good stability to the change of pH and film-forming property. Therefore, polyurethane thickener has attracted much attention over the years (Liu et al., 2020; Xu et al., 2016). However, compared with APAT, the thickening effect of linear polyurethane thickener is dissatisfactory.
Pistacia atlantica fruit essential oil nanoemulsions (PAEO-NE), an effective antiangiogenic therapeutic and cell-dependent apoptosis inducer on A549 human lung cancer cells
Published in Inorganic and Nano-Metal Chemistry, 2022
Mahvash Vakili Karkanrood, Masoud Homayouni Tabrizi, Touran Ardalan, Mozhgan Soltani, Farzanehsadat Khadem, Toktam Nosrat, Soheila Moeini
Plant oils and essential oils are a significant part of natural bioactive compounds, but due to their hydrophobic structure, they have less solubility in hydrophilic solutions such as blood fluid. This is the main limiting factor for their medicinal applications. In this regard, changing their hydrophobic nature to a hydrophilic type may make them soluble and biocompatible, which is possible by encapsulating them with amphiphilic agents and creating a drug delivery system such as nanoemulsion.[28] The use of nanocarriers such as nanoemulsion can reduce toxicity, increase half-life, and targeted delivery of bioactive compounds in chemotherapy.[29] Nano-based drug systems are significantly associated with improved drug efficacy and safety. Due to the nanometer size, drug-containing nanoemulsion droplets can easily enter tumor tissue, which increases the effectiveness of drugs.[30,31]
Fabrication and characterization of porous, degradable, biocompatible poly(vinyl alcohol)/tannic acid/gelatin/hyaluronic acid hydrogels with good mechanical properties for cartilage tissue engineering
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Changxin Xiang, Zijian Guo, Zehua Wang, Jianan Zhang, Weiyi Chen, Xiaona Li, Xiaochun Wei, Pengcui Li
The moisture content of hydrogels is illustrated in Figure 4a. The moisture content of PT, PTGH1, PTGH2 and PTGH3 hydrogels was 83.8 ± 1.04%, 85.7 ± 0.95%, 88.8 ± 1.16% and 91.3 ± 0.64%, respectively. According to previous studies, the high water content was probably due to addition of Gel and HA, which contained abundant hydrophilic groups [32]. The hydrophilic groups could easily form hydrogen bonds with water molecules and retain water molecules. Therefore, the water content of hybrid hydrogels increased with the GH content increasing. The high water content could provide PTGH hydrogels with a good lubrication effect and the friction coefficient as cartilage tissue regenerate materials [33].