Simultaneous quantitative determination of diazepam and liposomes using differential pulse polarography

The need for evaluating the retention of drugs in liposomes has lead to dev elopment of a new methodology, based on the differential pulse polarography (DPP), for the simultaneous quantitative determination of non-entrapped di azepam (DZP) and PC liposomes in a buffered solution, pH 7.4, at 37 degrees C, It was found that DZP polarographic signal depends both on liposome con centration and liposome size. Calibration plots of the DZP concentration vs , the current intensity in the presence of different lipid concentration we re constructed. The liposome and DZP concentration were determined using th ese plots and the "standard addition" technique, The DPP detection limit fo r DZP was found to be 15 mu g l(-1) while for liposomes in samples with 6 m g l(-1) DZP was calculated to be 0.01 mg ml(-1). (C) 1999 Elsevier Science B.V, All rights reserved.