Surface engineered nanostructured lipid carriers for targeting MDR tumor: Part II. In vivo biodistribution, pharmacodynamic and hematological toxicity studies.

Irinotecan loaded nanostructured lipid carrier (NLC-Ir) was surface decorated with hyaluronic acid graft polymer. Hyaluronic acid is a biocompatible, non-antigenic and hydrophilic, CD-44 ligand that can impart many useful features to the nanocarrier for anticancer drug delivery. The present investigation demonstrated that hyaluronic acid coated HA-NLC had significantly lower haemolytic potential as compared to uncoated NLC. Further, HA-NLC had a reduced plasma protein interaction and low macrophage uptake. The in vivo tumor targeting and pharmacodynamics efficacy of HA-NLC was studied in Ehrlich's Ascites Tumor (EAT) allograft model. Radio scintigraphic biodistribution studies revealed that HA-NLC carrier got accumulated in the tumor tissues in good proportion. Additionally, the content of radioactivity associated with tumor tissues remained constant at 2, 4 and 24 h (2.41, 2.48 and 2.47%, respectively), while it got reduced in other organs. Furthermore, tumor to muscle ratio of radioactivity suggested a better accumulation of HA-NLC in tumor tissues that was significantly enhanced (P<0.05) with time. In vivo antitumor activity of hyaluronan coated HA-NLC-Ir was 5.8 and 2.6 times higher as compared to control and free drug solution respectively. Furthermore, encapsulation of irinotecan in HA-NLC-Ir nanocarrier was found to have reduced the thrombocytopenia and neutropenia associated with free irinotecan. Thus, it can be inferred that the hyaluronic acid decorated nanocarrier can provide a haemo-compatible, non-toxic and target based delivery system for the effective management of cancer.

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.