Surface engineered nanostructured lipid carriers for targeting MDR tumor: Part I. Synthesis, characterization and in vitro investigation

Over expression of P-glycoprotein (P-gp) in cancer cells often results in highly aggressive, multi-drug resistant (MDR) phenotype. Such tumors are very difficult to treat with conventional therapy and often lead to failure of the treatment. In this work, we fabricated surface engineered hybrid lipid nanoparticles grafted with novel AL-HA polymer by mineralization technique. AL-HA graft polymer was prepared by covalent conjugation of alendronate sodium and hyaluronic acid. Compritol ATO 888 and capmule MCM C8 hybrid lipid mix was employed to prepare irinotecan containing nanostructured lipid carrier (NLC) by using functional excipients with P-gp inhibition activity. AL-HA was successfully grafted over NLC-Ir (uncoated irinotecan loaded NLC) by calcium-assisted mineralization. HA-NLC-Ir (hyaluronic acid coated irinotecan loaded NLC) particles have a nanoscale size of 386 +/- 2.2 nm along with a zeta potential value of 19.7 +/- 1.2 mV. NLC-Ir as well as HA-NLC-Ir showed a slow and sustained drug release. In vitro cell line studies performed on HT-29 and Colo-320 colon cancer cells revealed a reduced IC50 even in MDR cells. Flowcytometry studies demonstrated the capability of the developed nanocarriers to deliver the P-gp substrate moieties in MDR cancer cells. Furthermore, the targeting potential of HA-NLC was confirmed by CLSM studies. The cell line studies also revealed that NLC formulation had a potential of inhibiting P-gp by affecting ATPase activity and MDR1 gene expression. (C) 2014 Elsevier B.V. All rights reserved.