You can do dialysis, and look for your drug via UV-vis spectroscopy (see article http://www.sciencedirect.com/science/article/pii/S0378517301007219)

Also, if you have an opportunity to do, you can try this:

http://www.sciencedirect.com/science/article/pii/S0378517312010745

Cheers

you can indirectly calculate by Uv-vis spectroscopy

Drug encapsulated = 100*(Drug added-drug free/(liposome+drug)

here is the reference

acta biomaterialia 6(2010) 2732-2739

Maybe it is possible the following way using anionic surfactant selective electrodes:

add a defined amount of anionic surfactant to peptide without liposomes, to liposomes without peptide and to liposomes loaded with peptide, then calculate.

By the way peptides are not hydrophilic but amphiphilic.

Dear Natascia

Articles below may be helpful for you

- Carina Pimentel Itapema Alves1; Danielle Guimarães Almeida Diniz1 ; Eliana Martins Lima1*

Study of isotretinoin encapsulation into liposomes

Electronic Journal of Pharmaceutics

ISSN 1808-0804 Vol. IV (1), 79-85, 2007

- SINGH, A. K.; DAS, J. Liposome encapsulated vitamin A compounds exhibit greater stability and diminished toxicity. Biophysical Chemistry. v.73, p. 155-162, 1998

- MEHTA, K.; SADEGHI, T.; MCQUEEN, T.; LOPEZ-BERESTEIN, G. Liposome encapsulation circumvents the hepatic clearance mechanisms of all-trans-retinoic acid. Leuk. Res. v.18, p. 587-596, 1994

- VEMURI, SRIRAM.; RHODES, C. T. Preparatation and characterization of lipossomes as therapeutic delivery systems:

a review. Pharm Acta Helv. v. 70, p.95-111, 1995

You can use ultracentrifuge or dializing in order to separate liposomes from free drug. And the evaluate the analite indirectly or directly using UV or HPLC.

Hi,

for UV analysis. The blank has to contain solvent+ blank microparticles right?

Hi colleagues,

Attached papers describe encapsulation efficiency evaluation of different types of liposomes and nanoliposomes encapsulating different drugs: