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Nanoparticles — Preparation and Applications
Published in Max Donbrow, Microcapsules and Nanoparticles in Medicine and Pharmacy, 2020
More recently, attempts have been made to use the process of polymerization in an organic continuous phase for the production of polyalkylcyanoacrylate nanoparticles. Poly-methylcyanoacrylate,49-52 polyethylcyanoacrylate,49,52 and polybutylcyanoacrylate49,52 nanoparticles were produced using cyclohexane, isooctane, chloroform, dichlormethane, n-pentane, rc-hexane, butanol, toluol, castor oil, and/or isopropyl myristate as the organic phase. Polysorbate 2049 and 81,52 Arlacel A®,49 sodium dioctylsulfosuccinate,51 poly-hydroxyethylen-4-laurylether,52 sorbitan monolaurate,52 sorbitan monopalmitate,52 sorbitan monostearate,52 sorbitan trioleate,50 and Cremophor RH 40®50 were used as the emulsifiers. The drugs used were doxorubicin,49 fluorescein,49 triamcinolone,50 pilocarpine,52 and timolol.52 The drugs are dissolved in a small amount of water that is solubilized by the surfactants in the organic phase. For this solubilization, higher amounts of surfactants are required than by polymerization in an aqueous phase. The monomers are then either added directly to52 or dissolved in organic solvents.49,51 Upon contact of the monomer molecules with the solubilized water molecules, the polymerization is initiated (Figure 1).
1,4-Dioxane Chemistry, Uses, and Occurrence
Published in Thomas K.G. Mohr, William H. DiGuiseppi, Janet K. Anderson, James W. Hatton, Jeremy Bishop, Barrie Selcoe, William B. Kappleman, Environmental Investigation and Remediation, 2020
Food additives have been regulated in the United States and Europe for their 1,4-dioxane content. The U.S. Food Chemicals Codex restricts residual 1,4-dioxane content in polysorbates to 10 mg/kg. Polysorbate 60 [polyoxyethylene (20) sorbitan monostearate] is an emulsifier used in ice cream, frozen custard, ice milk, fruit sherbet, and other frozen desserts. Polysorbate 60 is used alone or in combination with polysorbate 65 and/or polysorbate 80. Polysorbates have been found to contain trace levels of 1,4-dioxane and ethylene oxide as impurities, which result from the production processes used for polysorbates (FDA, 1999). Polysorbate 60 and polysorbate 80, which are produced from the polymerization of polyoxyethylene, have historically been found to contain 1,4-dioxane (Birkel et al., 1979). Levels of 1,4-dioxane in these compounds have been reported to range from 5 to 6 ppm (mg/L) (ATSDR, 2004).
Telechelic Polycarbonates
Published in Sophie M. Guillaume, Handbook of Telechelic Polyesters, Polycarbonates, and Polyethers, 2017
In the absence of any catalyst, a trifunctional poly(ethylene glycol) (PEG)-based surfactant, namely poly(oxyethylene sorbitan monolaurate), initiated the ROP of TMC (bulk, 150°C) providing amphiphilic star-shaped poly(oxyethylene sorbitan monolaurate)-b-PTMC copolymers in excellent yields (Mn = 4500–11,900 g.mol−1; Scheme 6.44) [131]. The copolymers were successfully dispersed in a water/ethyl acetate mixture, and the resulting uniform suspension could incorporate a hydrophobic pigment and a fluorescent probe, thus highlighting potential drug delivery opportunities.
Effect of ZnO nanoparticles doping on structural, dielectric and interfacial behavior of polyoxyethylene (20) sorbitan/ethylene glycol lyotropic phases
Published in Soft Materials, 2021
Lyotropics are the self-assembled soft molecular structures derived from surfactants (ionic and nonionic) in the presence of solvents (water or organic ones).[1-2] Owing to the self-assembling nature and orientational ordering, these materials are recognized as a functional material and extensively explored in the fields of electronics, nanotechnology, solar cells energy.[8–10] Apart from this, the self-organizing nature of LLCs shows the close analogy with biological systems and are also being used in biomedical, food technology, pharmaceutical (drug delivery) and structural biology.[11] In this report, we limit our discussion on the nonionic surfactants and their LLC phases only. Nonionic amphiphiles are an important class of surfactants and they are well known for their low toxicities and high effectiveness even at low concentrations.[12] As far as the LLCs phases concerned, binary and ternary mixtures of polyoxyethylene (EO),[13] Triton X-114, Brij-35, Brij-700, Tween-20, Triton X-100)[14] and polysorbates are the commonly studied nonionic surfactant systems for this cause.[15] Polyoxyethylene sorbitan also has excellent emulsifying properties and is being prominently used in the pharmaceutical industry, food and as aerating agents and lubricants.[13,16,17]
Physical features’ characterization of the water-in-mineral oil macro emulsion stabilized by a nonionic surfactant
Published in Journal of Dispersion Science and Technology, 2022
This study aims to assess the bulk properties and main features of the water-in-mineral oil emulsions stabilized by a nonionic surfactant (Span 83). Sorbitan sesquioleate (Span 83) from the Span nonionic surfactant family is widely used as an emulsifier for the formulation of the creams and ointments for cosmetic use and pharmaceuticals.[17]Figure 1 displays the chemical structure of Span 83, and Table 1 summarizes the properties of this type of surfactant. The low HLB value of Span 83 indicates higher solubility in the oil phase and according to Bancroft’s rule, this will facilitate the formation of the w/o emulsion.