1. From the well-known opinion the term self is refered to nanosized microemulsions that are thermodynamically stable. Nanoemulsion are kinetically stable and are not formed by self-organization process.

2. In any case when you dissolve a drug in the some type of emulsion this drug is solubilized in this kind of solvent. Where the drug molecule localized depends on the type of nanoemulsion water/oil, oil/water or bicontinues state. Depending on the drug nature (hydrophobic, hydrophilic or diphilic it can solubilized inside of oil or water core or at the interface between water and oil. 

3. In the case of nanoemulsion it is difficult to speak about classical micelles because we have some nanodrops of water and oil separated by surfactant.

3. Because drug usually has no long hydrophobic tail it is not micelle-froming component but additional component that can solubilize in the microheterogeneous system. Some physical methods like NMR can help to determine the localization the drug in nano(micro)emulsiom.

I don't think so. The mechanism of surfactant improving drug solubility is they can form micelles. So, I think the two forms are actually same thing.

you can identified by MSR when drug solubilize in surfactant. If your drug is amphiphilic, try to find out the cmc /critical micelle concentration of that drug.

The drug may be amphiphilic. Therefore, it forms a mixed micelles with the surfactant. If the drug is poorly soluble in water, it is solubilized in the micelles.

Best regards.

 I thank to these answer, but if we make a self nano emulsion formulation, it contains a high amount of surfactant thus incorporated drug i.e. poorly water soluble probably entrapped in globule or solubilized by micelle, who to distinguish between them?

If the drug is dissolved in the micelle has a solubilization. If the drug is dissolved in the emulsion, the emulsification is called,i.e. poorly water soluble probably entrapped in globule (hydrocarbon).

thanks a lot sir

1. From the well-known opinion the term self is refered to nanosized microemulsions that are thermodynamically stable. Nanoemulsion are kinetically stable and are not formed by self-organization process.

2. In any case when you dissolve a drug in the some type of emulsion this drug is solubilized in this kind of solvent. Where the drug molecule localized depends on the type of nanoemulsion water/oil, oil/water or bicontinues state. Depending on the drug nature (hydrophobic, hydrophilic or diphilic it can solubilized inside of oil or water core or at the interface between water and oil. 

3. In the case of nanoemulsion it is difficult to speak about classical micelles because we have some nanodrops of water and oil separated by surfactant.

3. Because drug usually has no long hydrophobic tail it is not micelle-froming component but additional component that can solubilize in the microheterogeneous system. Some physical methods like NMR can help to determine the localization the drug in nano(micro)emulsiom.

Now I get your point. In nanoemulsions both micelles and surfactant-stabilyzed droplets (the dispersed phase) coexist in the continuous phase. So the lipofilic drug can be inside of the micelles or in the droplets. I have the same doubt in how to measure it, perhaps by the differences in the diffusion/mobility. Following up this question, hope anybody can help us with this! BR

Dear Prof.Sergei Nikolaevich Shtykov and Prof.Yuri Mirgorod,

Thanks. Very good comment.

Best,

Abbas

After reading the question and the answers I could only add. I see the question next:

What are possibilities to choose colloid carrier of the drug?

There are two types of colloid carriers, i.e. colloid systems

1.     Colloid solution

• ·         Single surfactant molecules (Csurf < CMC),

                        Not suitable as a currier

• ·         Micilles formed by surfactant association (Csurf > CMC),

                        Drug molecules unpolar or low polar can be solubilized within the

                        micelles

• ·         Mixed micelles made of surfactant and amphiphilic drug molecules

2.     Colloid dispersion (oil in water emulsion)

• ·         Nanoemulsion spontaneously formed (microemulsion), besides surfactant usually  cosurfactant is needed. Surface pressure within the surfactant/cosurfactant film around droplets is different leading to negative surface tension and thermodynamic stability of the system.
• ·         Nanoemulsion formed by high pressure homogenizer                     System does not possess thermodynamic stability

In both cases oil soluble drug are to be dissolved in disperse oil phase prior to emulsion formation.

What way will be used depends of the user and circumstances.

You may try to judge based on turbidity or translucence. In that case you have dispersed drug in nano- or micro dispersion. Same if after centrifugation you obtain a turbid/translucent and a clear layer. Otherwise you have a solution, i.e. solubilized drug.