Can anyone suggest how to estimate drug distribution in all the phases(i.e is oil phase, aqueous phase and micells) of a oil-in-water nanoemulsion??
Dear Shanker Mamid;
Distribution of the drug between the hydrocarbon and water microemulsion can be determined by 13C NMR. Measure the time of the spin-lattice and spin-spin relaxation.
Nakagava T. Surf. and Colloid Sci ( Wiley. 1976.
Best regards.
Dear sir ,
I need to prove by HPLC after separation of each phase ( Oil phase, Aqueous phase and micelles) with validations.some reported articles are says by ultracentrifugation and microdialysis method.is there any other breaking process is there to break the emulsion.plz suggest me .
Your system: water (greater ) / hydrocarbon (fine droplets, less) / surfactant (surface interface, very little) / drug. It is a dynamic system. If you remove some of the water by chromatography or centrifugation, then it changes. Changes and redistribution of the drug. Changing the ratio of the substances can not be in the system.
Regards.
Do you mean the drug distribution in terms of dispersed droplet phase in continuous phase nanoemulsion?
if yes, I think you may use DLS (Dynamic Light Scattering) technique.
Dear Atthaphon,
As you said DLS technique is for measurement of Globule size(if am not worng ) in terms of Intensity of various globules in different sizes.I need to know the drug in oil phase and aqueous phase and micelles.
You can use ultracentrifugation. You will have a lipid phase, aqueous phase and the pellet phase. From that, you can separate and dilute each of the phases with a proper solvent and then quantify the drug concentration by HPLC. You may have a look on the publications of Philip Sassene et al.
Dear Scheyla,
How to find out drug concentration in oil-water interface and micelles
Dear Shanker,
Emulsion as such is the dispersion of a liquid phase into another liquid. They disperse in the form of droplets. An emulsion should be of single phase. When you are able to separate the phase and study the drug concentration in each phase, that is not a stable emulsion at all.
So, you do not have to study the drug distribution among the phases, since emulsion is single phase system, as per definition.
Good luck
absolutely not - emulsion is at least a two phase system, with at least one kind of interface. Therefore the question about drugs concentration in interface and in micelles.
In a first approximation one might assume that ratio of drug/surfactant is about the same at interface and in micelle. Therefore one might first study the distribution in 2 phase system oil/surfactant solution at or just below cmc. For surfactant partially soluble in oil this will be even more complex, but easier for a common ionic surfactant.
Depending on whether drug is better soluble in oil or water I would start this with determining oil-water partition coefficient overlaying the 2 phases (minimize volumes, maximize interface), followed by using surfactant solutions.
Dear Abdul Azeez,
Thanks for your reply,
Actually my question is drug estimation in different phase like oil and aqueous phase.how much drug entrapped in oil and how much drug is in free aqueous phase.
You need to break the emulsion first and centrifuge using high speed centrifuge and check the drug concentration in those two phases. The presence of micelles in respective phases are determined using DLS technique. emulsion breaking shall be done by lowering pH + addition of salt. or Add salt and heat the emulsion and then centrifuge or Phase inversion temperature technique shall be used. Since at higher temperatures the CMC of the surfactant breaks.
heat will and salt addition might change the partition in oil/water phases
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