Abstract
Purpose :
Evaluate the potential of a cationic calixarene-based nanoaggregate as a novel nanocarrier for curcumin ocular delivery by investigation of anti-inflammatory effects.
Methods :
An amphiphilic self-assembling calix[4]arene derivative bearing 4 choline groups was loaded with curcumin to give a clear colloidal solution in PBS. Size, polydispersity index, and surface charge of the nanostructured system were derived from DLS analysis and zeta potential measurements. UV-vis spectroscopy and HPLC analyses were performed to study solubility and chemical stability of curcumin alone and loaded in the system. Curcumin, calixarene and curcumin-loaded calixarene were used to test biocompatibility on corneal cells and J774 murine macrophage cells (MTT assay) and to evaluate in vitro/in vivo anti-inflammatory effects. On J774 cells pre-treated (2h) and post-treated (24h) after LPS-stimulation, western blot analysis were performed to test the expression of inflammation markers. Following treatment for 3 days before and 7 days after induction of uveitis by injection of LPS, rats were sacrificed (16 and 72 hrs) and eyes taken to perform histology and immunohistochemical staining.
Results :
The curcumin-loaded calixarene showed a mean hydrodynamic diameter of 82 nm, polydispersity index of 0.2 and zeta potential of +23 mV. The drug loading capacity was 10%. Calixarene enhanced curcumin solubility and chemical stability. No cytotoxicity was reported using curcumin alone (range 0.00125-0.05 mg/ml) and calixarene with or without curcumin (range 0.015-0.25 mg/ml). The higher anti-inflammatory activity of the curcumin-loaded calixarene was shown through the modulation of NF-κB activation, reduction of IκBα degradation, COX-2, iNOS expression and nitrite levels (p<0.0001 vs LPS control). In vivo studies confirmed the anti-inflammatory effects of curcumin and particularly of the curcumin-loaded calixarene.
Conclusions :
An amphiphilic calix[4]arene derivative that self-assembles in discrete cationic nanoaggregates was designed to optimize the delivery of curcumin. The capability to improve solubility, stability, and bioavailability of curcumin as well as the enhanced anti-inflammatory effects observed in vitro and in vivo make of the calixarene nanoaggregate an innovative and promising carrier for ocular drug delivery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.