Tailoring the efficacy of nimodipine drug delivery using nanocarriers based on A2B miktoarm star polymers

Ghareb M. Soliman, Rishi Sharma, Angela O. Choi, Sunil K. Varshney, Françoise M. Winnik, Ashok K. Kakkar, and Dusica Maysinger,


BiomaterialsVolume 31, Issue 32, November 2010, Pages 8382-8392

[center]Abstract
We report a nanocarrier based on A2B type miktoarm polymers (A = polyethylene glycol (PEG); B = polycaprolactone (PCL)) for nimodipine (NIM), a hydrophobic drug with very poor aqueous solubility that is commonly prescribed for the prevention and treatment of delayed ischemic neurological disorders. The A2B star polymers were constructed on a core with orthogonal functionalities that facilitated the performance of “click” chemistry followed by ring-opening polymerization. These star polymers assemble into spherical micelles into which NIM can be easily loaded by the co-solvent evaporation method. The micelles obtained from the star polymer PEG7752–PCL5800 showed NIM encapsulation efficiency of up to 78 wt% at a feed weight ratio of 5.0%. The loading efficiency of the micelles was dependent on the length of the PCL arm in the A2B miktoarm polymers. Aqueous solubility of NIM was increased by 200 fold via micellar encapsulation. The in vitro release of NIM from the micelles was found to occur at a much slower rate than from its solution. Lipopolysaccharide induced nitric oxide production in N9 microglia cells was reduced in the presence of micelle-encapsulated NIM, as well as in the presence of micelles alone. The treatment of microglia with micelle-encapsulated NIM reduced the release of TNF-α, a pro-inflammatory cytokine. These results suggest that NIM-loaded miktoarm micelles could be useful in the treatment of neuroinflammation.
Keywords: Nimodipine; Miktoarm; Micelle; Drug delivery; Neuroinflammation; Microglia