Enhancing 31P NMR relaxation rates with a kinetically inert gadolinium complex

The heptadentate gadolinium complex Gd.pDO3A (1.Gd) generates significant 31P nuclear magnetic resonance (NMR) relaxation enhancement of biologically relevant phosphate species; adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate.

Theranostic polymeric nanocarriers modified by enhanced gadolinium conjugation techniques

Background: Efficient delivery of the poorly water-soluble compound sorafenib still poses a challenge to current formulation strategies. To incorporate the lipophilic molecule into biocompatible and biodegradable theranostic nanoparticles has great potential for improving efficacy and safety of cancer therapy. Results: In this study, sorafenib nanoencapsulation was optimized using poly(D,L-lactide-co-glycolide) and polyethylene glycol-poly(D,L-lactide-co-glycolide) copolymers comparing three different technologies. The particles ranged in size between 220 and 240 nm with encapsulation efficiencies from 76.1 ± 1.7 % to 69.1 ± 10.1 %. A remarkable maximum drug load of 9.0 % was achieved. Finally, a gadolinium complex was covalently attached to the nanoparticle surface transforming the nanospheres into theranostic devices allowing the localization using magnetic resonance imaging. Conclusion: The manufacture of sorafenib-loaded nanoparticles and the functionalization of the particle surface with a gadolinium complex resulted in a high drug loading, a strong MRI signal, optimal stability features and a sustained release profile.