(1R)-1-[3-Hydroxy-3-oxido-8-oxo-10-(2-pyridinyldithio)-2,4-dioxa-7-aza-3-phosphadec-1-yl]-1,2-ethanediyl Ester Hexadecanoic Acid Monosodium Salt is a paramagnetic pH sensitive liposome that can be used as imaging tools for visualizing drug-delivery and release processes by Magnetic Resonance Imaging (MRI).