Curcumin is not soluble in water, so when it is released from nanoparticles it will just precipitate and will not be able to pass through the dialysis membrane. Adding a detergent such as Tween to the system may keep the curcumin from precipitating, but the micelles of detergent are too large to pass through the dialysis tubing. A possible solution would be to use a different detergent, one with small micelles such as CHAPS, and also use a dialysis membrane with a high molecular weight cutoff, such as 100,000.

Here is a table of detergent properties:

http://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Instructions/detergent_selection_table.pdf

Dear Sir, Solubility is the main problem, curcumin is not soluble at all and thus will not pass through the membrane but gets collected and settles. Thanks

Is there another better way to investigate in vitro release of curcumin from liposomes?

You might be able to separate liposomal from non-liposomal curcumin by density gradient centrifugation. Since the expectation is that curcumin released from liposomes will precipitate, it should be possible to pellet it through a layer of a sucrose solution of a certain density, whereas the liposomes will remain on top. You would have to experiment to see whether there is a suitable sucrose concentration. It will also depend on the nature of the liposomes.

Thanks a lot. We actually use simple centrifugation to separate different size of liposomes.