Magnetic silica hybrids modified with guanidine containing co-polymers for drug delivery applications

Guanidine containing co-polymers grafted onto silica nanoparticles to form core-shell structure were prepared by sol-gel method in the presence of gamma-Fe2O3 nanoparticles. The morphological features for uncoated and coated silica particles have been characterized with scanning electron microscopy. The results show that the polymer coated silicas exhibit spherical morphology with rough polymeric surface covered by gamma-Fe2O3 nanoparticles. The grafting amount of guanidine containing co-polymers evaluated by thermogravimetric analysis was in the range from 17 to 30%. Then, the drug loading properties and cumulative release of silica hybrids modified with guanidine containing co-polymers were evaluated using molsidomine as a model drug. It was shown that after polymer grafting the loading content of molsidomine could reach up to 3.42 +/- 0.21 and 234 +/- 0.14 mg/g respectively. The maximum drug release of molsidomine is achieved at pH 1.6 (approximately 71-75% release at 37 degrees C), whereas at pH 7.4 drug release is lower (50.4-59.6% release at 37 degrees C). These results have an important implication that our magneto-controlled silica hybrids modified with guanidine containing co-polymers are promising as drug carriers with controlled behaviour under influence of magnetic field. (C) 2016 Elsevier B.V. All rights reserved.