Open AccessIn vitro characterization of phosphatidylglyceroglycerol‐based thermosensitive liposomes with encapsulated 1 H MR T 1 ‐shortening gadodiamide
Author(s) -
Wang Tungte,
Hossann Martin,
Reinl Herbert M.,
Peller Michael,
Eibl Hansjoerg,
Reiser Maximilian,
Issels Rolf D.,
Lindner Lars H.
Publication year - 2008
Publication title -
contrast media & molecular imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.714
H-Index - 50
eISSN - 1555-4317
pISSN - 1555-4309
DOI - 10.1002/cmmi.226
Subject(s) - gadodiamide , nuclear magnetic resonance , chemistry , nanocapsules , materials science , gadolinium , nuclear medicine , analytical chemistry (journal) , chromatography , medicine , nanotechnology , nanoparticle , physics , organic chemistry
Thermosensitive liposomes (TSL) with encapsulated proton ( 1 H) magnetic resonance (MR) contrast agents have been proposed for noninvasive online temperature monitoring during tumor treatment using chemotherapy combined with hyperthermia (HT). The technique exploits the fact that water exchange between the TSL interior and exterior is increased and/or the encapsulated 1 H MR contrast agent is released near the gel‐to‐liquid crystalline phase transition temperature ( T m ) of TSL and thus shortens the 1 H MR relaxation time of tissue. In this work, newly developed, phosphatidylglyceroglycerol (DPPGOG)‐based TSL with encapsulated 1 H MR longitudinal relaxation time ( T 1 )‐shortening gadodiamide (Gd‐DTPA‐BMA) were characterized in vitro by measuring the temperature dependence of the T 1 of these gadodiamide‐containing DPPGOG‐TSL samples between 30 and 50°C. The measurements revealed that the T 1 nonlinearly slightly decreased with increasing temperature from 30 to 37°C, mainly due to increased water exchange between the gadodiamide‐containing DPPGOG‐TSL interior and exterior with the exception of negligible gadodiamide release. This implies that gadodiamide‐containing DPPGOG‐TSL were stable at temperatures ≤37°C, which was also confirmed by an independent stability study. From 37 to 44°C, the T 1 nonlinearly markedly decreased with increasing temperature since encapsulated gadodiamide was rapidly released. Above 44°C, gadodiamide was completely released and the T 1 was directly proportional to temperature while heated from 44 to 50°C and cooled from 50 to 30°C, respectively. Additionally, gadodiamide release was theoretically quantified and this calculated concentration was consistent with the actually released amount directly obtained from the cooling course of empty DPPGOG‐TSL with completely released gadodiamide. Copyright © 2008 John Wiley & Sons, Ltd.