Antiviral Nanomaterials as Potential Targets for Malaria Prevention and Treatment
Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji in Viral and Antiviral Nanomaterials, 2022
This method is a variation of SEE. The drug and lipid excipients are dissolved in a partly water-miscible organic solvent, and the resulting mixture is then saturated with water to reach thermodynamic equilibrium between the two liquids. Since the organic solvent is partly miscible with water, it diffuses into it, causing lipid NPs to precipitate from the dispersed process. This technique can generate NPs with a size of less than 100 nm and a low polydispersity index. Further, the solvent from the system could be eliminated by evaporation or filtration. Nonionic surfactants lead to the formation of larger particles than ionic surfactants (Pineda-Reyes et al. 2021). This technique offers many advantages, such as high encapsulation efficiency, good reproducibility, avoidance of homogenization, easy scale-up, and narrow particle-size distribution. Process parameters such as polymer and surfactant nature and concentration, type of solvent, agitation speed and time, type of stirrer, temperature of dilution water, and viscosity of external phase affect the properties of prepared nanoparticles. The main disadvantages of this method are the removal of large amounts of water from suspension and the risk of hydrophilic drug leakage into the aqueous external process during emulsification.
Silicone oil in the anterior chamber
A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha in Vitreoretinal Surgical Techniques, 2019
After six months, silicone oil can appear in the anterior chamber in emulsified form. The emulsification is the result of fragmentation of the oil globule into multiple micelles, resulting from the interaction of the oil with molecules containing both hydrophilic and lipophilic elements. The process is analogous to the effect of soap on oil in water. While an IPI has been well demonstrated to prevent accumulation of nonemulsified silicone oil in the anterior chamber in the short-term postoperative course, it is not effective in preventing the long-term accumulation of emulsified oil.4 The rate of emulsification is correlated only with the duration of silicone oil in the eye, although aggressive postoperative inflammatory control may help to reduce plasma constituents that would accelerate emulsification.
Surfactants in Cosmetic Products
Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters in Cosmetic Formulation, 2019
Likewise, the HLB of the emulsifier system to be used to emulsify an oil phase (mixture of emollients) is calculated as the weighted average amount of emulsifier multiplied by the HLB of each. In this way, the HLB of the oil phase mixture can be made compatible with that of the emulsifier system. As an example, if it is desired to emulsify a paraffin with an HLB of 10, a mixture of emulsifiers of which HLB is 9 to 11 will be required. In addition, the rules of chemical compatibility and amount of emulsifier should be observed to obtain a stable emulsion. From the practice of emulsion processing, it has been established that the amount of emulsifier to be used represents 20 to 25% by weight of the oil phase. If the resulting product has good stability, the amount of emulsifier may be reduced. With an insufficient dose of emulsifier, emulsion breakdown and phase separation will occur. With an excessive amount of emulsifier, an excess of micelles occurs and that favours the cutaneous absorption of active vehicles and may reduce the viscosity of the emulsion.
Self-emulsifying drug delivery systems: a novel approach to deliver drugs
Published in Drug Delivery, 2022
Self-emulsification is influenced by the quality and nature of the concentration of surfactants, pair of oil/surfactant, and oil/surfactant ratio, and the physiological parameters in which it happens, including pH, and temperature. SEDDSs vary from conventional oral drug delivery systems in that digestion of enzymes significantly changes the excipients in the formulation (Amara et al., 2019). Gastric and pancreatic lipases hydrolyze the lipids in the oil phase of SEDDSs in the GIT, releasing additional amphiphilic lipid digestion products. The solubilization of biliary lipids secreted in the bile is quick and these released digested lipids. Different parameters are linked with the gastrointestinal lipolysis process during lipid digestion. These parameters include pancreatic and gastric lipase secretions, the difference in the small intestine’s pH in and the stomach, pH of the lipase action, and secretions of the bile that allow solubilization of micelle by lipolysis products (Park et al., 2020; Sirvi et al., 2022).
Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions
Published in Expert Opinion on Drug Delivery, 2022
Arya Kadukkattil Ramanunny, Sachin Kumar Singh, Sheetu Wadhwa, Monica Gulati, Bhupinder Kapoor, Rubiya Khursheed, Gowthamarajan Kuppusamy, Kamal Dua, Harish Dureja, Dinesh Kumar Chellappan, Niraj Kumar Jha, Piyush Kumar Gupta, Sukriti Vishwas
While preparing NANEs, generally, the lipophilic drugs are solubilized in the oil phase. Upon mixing of oil phase with surfactant-co-surfactant (Smix) and dispersion medium, emulsification process begins. During the process, the lipophilic drug stays inside the oil droplets. The oily matrix protects the encapsulated drug from the oxidation and hydrolytic degradation [91]. In case of Pickering emulsions, where the traditional surfactant is substituted with solid particles such as silica nanoparticles, clay, etc., also the drug resides in the oil matrix and solid particles accumulate at the interface of the immiscible phases. This ensures efficient stabilization of the system [92]. Schematic representation of drug encapsulation in NANEs and Pickering NANEs is shown in Figure 1.
In-vitro and in-vivo evaluation of taste-masked ibuprofen formulated in oral dry emulsions
Published in Drug Development and Industrial Pharmacy, 2021
Haojun Qi, Jiening Dun, Feng Zhao, Xiaodan Qi
An emulsion is a dispersion of two immiscible liquids, in which one liquid is dispersed in the other liquid in the form of droplets under the influence of an emulsifier. The oil-in-water emulsion has been recognized as an effective and stable carrier delivery system for lipophilic drugs. The taste-masking effect is realized by encapsulating the drug in emulsion drops to reduce contact with taste receptors. However, the emulsion is a thermodynamically unstable system, in which unstable physical phenomena such as creaming, flocculation, and demulsification occur easily [18], which can adversely affect production, storage, transportation, and application. These problems can be mitigated by transforming a liquid emulsion into a dry emulsion [19]. Dry emulsions are typically prepared by adding water-soluble materials into liquid emulsions, and the moisture is removed by e.g. spray drying, freeze-drying and vacuum distillation, to give solid particles or powder. The oil phase remains, so the dry emulsion can be rapidly dispersed in added water and restored to a homogeneous emulsion [20] suitable for oral administration to children.
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