Nanoparticles emulsion-solvent evaporation

Fig. 3 Preparation of polymeric nanoparticles by emulsion solvent evaporation technique...

In an effort to develop an effective bioadhesive system for buccal administration, insulin was encapsulated into polyacrylamide nanoparticles by the emulsion solvent evaporation method [98]. Though nanoparticle formation ensures even distribution of the drug, pelleting of the nanoparticles was performed to obtain three-dimensional structural conformity. In addition, it was hypothetized that the pelletized particles will remain adhered to the mucosa, leading to good absorption. While studying bioadhesion and drug release profiles, it was found that the... 

The most widely used emulsion solvent evaporation method for preparation of nanoparticles using PLGA requires surfactants to stabilize the dispersed particle [23]. This method often has a problem that the surfactant remains at the surface of the particles and is then difficult to remove when PVA is used as surfactant. Other surfactants such as the span series or tween series, PEO, etc. are also used... 

Poly(s-caprolactone) Poly(e-caprolactone) is a semicrystalline polymer synthesized by anionic, cationic, free-radical, or ring-opening polymerization [94]. It is available in a range of molecular weights and degrades by bulk hydrolysis autocatalyzed by the carboxylic acid end groups. The presence of enzymes such as protease, amylase, and pancreatic lipase accelerates polymer degradation [95], The various methods of preparation of poly(e-caprolactone) nanoparticles include emulsion polymerization, interfacial deposition, emulsion-solvent evaporation, desolvation, and dialysis. These methods and various applications are extensively reviewed [94],... 

Poly(alkyl-cyanoacrylates) As poly(alkyl-cyanoacrylates) form strong bonds with polar substrates including the skin and living tissues, they exhibit bioadhesive properties. These polymers are synthesized by free-radical, anionic, or zwitterionic polymerization. As detailed in a recent review, poly(alkyl-cyanoacrylate) nanoparticles are prepared by emulsion polymerization, interfacial polymerization, nanoprecipitation, and emulsion-solvent evaporation methods [102],... 

Emulsion Solvent Evaporation The basic concept of the emulsion solvent evaporation technique producing nanoparticles is very straightforward. The particles are formed as an emulsion of a polymer-surfactant mixture and dispersed in an organic solvent. The solvent is then evaporated to leave behind the individual emulsion droplets which form stable free nanoparticles [203], This method is far easier and more preferable over methods such as spray drying and homogenization and operates under ambient conditions and mild emulsification conditions. The size and composition of the final particles are affected by variables such as phase ratio of the emulsion system, organic solvent composition, emulsion concentration, apparatus used, and properties of the polymer [204],... 

Jaiswal J, Gupta SK, Kreuter J. Preparation of biodegradable cyclosporine nanoparticles by high-pressure emulsion-solvent evaporation process. / Control Release 2004 96(1) 169-178. 

If preformed polymers are used for the encapsulation of magnetic nanoparticles, a combination of miniemulsion and emulsion/solvent evaporation techniques... 

The main advantage of EHDA over conventional methods of micro-/nanoparticle production like emulsion/solvent evaporation is that EHDA eliminates or strongly decreases the need for surfactants. 

Synthesis of polymer microspheres in the presence of magnetic nanoparticles, such as suspension polymerization or its modified versions, dispersion polymerization, surface-initiated radical polymerization, acid-catalyzed condensation polymerization, emulsion polymerization, mini-/microemulsion polymerization, in situ oxidative polymerization, inverse emulsion cross-linking, emulsion/double emulsion-solvent evaporation, and supercritical fluid extraction of o/w miniemulsion... 

Liu D, Jiang S, Shen H, Qin S, Liu J, Zhang Q et al. Diclofenac sodium-loaded solid lipid nanoparticles prepared by emulsion/solvent evaporation method. Journal of Nanoparticle Research. 2011 13(6) 2375-2386. 

Water-soluble therapeutic proteins and peptides can be delivered using porous nanospheres or nanocapsules formed by a double emulsion solvent evaporation procedure. A concern with the delivery of proteins by nanoparticles is the loss of protein activity before its release. Desai et al. showed about 30% of tetanus toxoid activity was lost due after encapsulation and release from nanoparticles (Desai et al. 1996). Protein may be inactivated due to denaturation based on exposure to organic solvents and adsorption onto the oil-water interface during fabrication (van de Weert et al. 2000 Lu et al. 2000). A strategy for reducing adsorption of the therapeutic protein is the incorporation of human or bovine semm albumin in the aqueous phase, which restricts the access of the therapeutic protein to the phase interface (Kim and Park 1999). Another proposed cause of protein inactivation is decreased local pH experienced by the encapsulated protein due to acidic degradation byproducts. This can be addressed by including an alkaline buffer into the aqueous phase (Zhu et al. 2000). 

To improve the oral bioavailability of calcitonin, Garcia-Fuentes et al. used tripalmitate nanoparticles coated with chi-tosan or polyethylene glycol. The nanoparticles were prepared by a double emulsion solvent evaporation method that was adapted due to its high efficiency for the encapsulation of peptides. The nanoparticles were stabilized with soybean lecithin and the surface coating was done by incubation of the prepared lipid nanoparticles in a chitosan/poloxamer solution or by initial addition of PEG-stearate to the organic phase. Excess stabilizers were removed by centrifugation. Whereas... 

Lee M, et al. Size control of self-assembled nanoparticles by an emulsion/ solvent evaporation method. Colloid Polym Sci. 2(X)6 284 506-12. 

E. Pindn-Segundo, M.G. Nava-Arzaluz, D. Lechuga-Ballesteros. Pharmaceutical polymeric nanoparticles prepared by the double emulsion-solvent evaporation technique. Recent Pat DrugDeliv Formul. 6 (3) 224-235,2012. 

Recent Advances in the Emulsion Solvent Evaporation Technique for the Preparation of Nanoparticles and Nanocapsules... 

Abstract The emulsion solvent evaporation technique is a method for preparing nanoparticles and nanocapsules that are particularly adapted for applications requiring materials with high purity and low toxicity, such as for biomedicine or electronics. We discuss here new important advances concerning the elucidation of the mechanism of nanoparticle formation, and the synthesis of nanoparticles with new structures or from new polymers. 

Because the emulsion-solvent evaporation is versatile, new nanoparticles structures and nanoparticles from new materials are expected to be reported. Open questions such as how to create very monodisperse nanoparticles via this technique and the influence of the molecular state of the polymer on the nanoparticle and nanocapsule properties such as permeability are expected to be answered in the foreseeable future, helping to create more functional and useful materials. 

In a study, polymeric nanoparticles (NPs) composed of a new redox-responsive polymer, poly(ethylene glycol]-b-poly(lactic acid] [MPEG-SS-PLA], were prepared to carry paclitaxel [PTX] for glutathione (GSH]-regulated drug delivery. The PTX-loaded MPEG-SS-PLA NPs were fabricated using an optimized oil-in-water emulsion/solvent evaporation method. The HPLC results revealed that the NPs released almost 90% PTX within 96 h when GSH presented at intracellular concentrations, whereas only a very small PTX amount was released at plasma GSH levels. The MTT assay results show that the NPs caused concentration- and time-... 

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