I'm preparing polymeric nanoparticles using emulsification solvent evaporation method, but I haven't got the characteristic emulsion that indicates the nanoparticles formation.
by optimizing concentration of surfactant, oxidizer, and monomer concentration.
Hi Tatiana,
What do you mean by 'characteristic emulsion'?
Have you tried to measure particle size (hydrodinamic diameter)?
I guess by characteristic emulsion you meant stable suspension of nanoparticles. Try to vary the surfactant concentration or else use some other like PVA, SDS etc. Also, try to measure the zeta-potential of the final system to have better insight in the stability of the NP.
The formation of nanoparticles can be optimized by changing different variables such as solvent, type of surfactant and its concentration.
Only for the synthesis of monodisperse polymer microspheres, you can try to use the other synthetic techniques. There are many methods in this field. You can select the suitable one, which depends on the monomers.
Hello everyone
Dear Barbara: when I wrote "ccharacteristic emulsion" I mean a milky suspensión, but I got two phases (water and organic phase separately).
Dear Vibhore: you're right, I have been using 0.5 %w/w Poloxamer as a surfactant. And I had though in changing that concentration.
Dear Xinlin: today I tried to use double emulsion solvent evaporation technique (I hace read that that technique may be used to encapsulated hydrophobic drugs) , but, It was obviously so difficult to dissolved an hydrophobic drug in water.
Could you please advice me in double emulsion solvent evaporation technique articles ??
Thank you so muchos forma your answers... !!!!
Try this paper, it is all about double emulsion technique.
http://dx.doi.org/10.1016/j.biortech.2013.01.106
Poloxamer is a generic name applied to nonionic triblock copolymers with different ethylene oxide chain length and thus different HLBs within a range of 3 to 30 and above. They are a crowded family of different amphiphilic nonionic block polymers of hydrophobic propylene oxide and hydrophilic ethylene oxide. Poloxamers adsorb strongly onto the surface of hydrophobic droplets so they are good stabilizers. However, they are sensitive to temperature. The water solubility and surface activity of nonionic surfactants are dependent on the number of ether linkages in the polyoxyethylene chain, which are readily hydrated at room temperature. An increase in temperature reduces the forces of hydration, and the surfactants then become less soluble in water, and emigrate into the oil phase. This could be the reason that your emulsion becomes unstable at high temperatures (note that this is not a general rule as adversely a temperature rise can improve the emulsion stability, depending on the HLB of surfactant and its PIT). So selecting a right Poloxamer is essential (probably with HLB of around 14 to 18). You can easily check the stability of your emulsion at different temperatures to verify this. An ionic surfactant such as SDS, which is insensitive to temperature, can also be used.
The droplet size should also be reduced to the submicron range by using a homogeniser. It is much easier to evaporate a solvent when the droplet size is small, because of its large surface area. It also increases the likelihood of getting nanoparticles, as the solid contents in each droplet is minimised.
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