Yak interferon-alpha loaded solid lipid nanoparticles for controlled release

To explore the potential of a novel animal interferon formulation for controlled release, the yak interferon-alpha (IFN-alpha) glutathione S-transferase (GST) fusion protein was expressed in Escherichia coli (E. coli) and the purified recombinant IFN-alpha was encapsulated into solid lipid nanoparticles (SLN) by double emulsion solvent evaporation (w/o/w) method. The particle size and zeta potential of IFN-alpha-loaded SLN were 124.2 +/- 10.2 nm and -11.2 +/- 0.6 mV. The encapsulation efficiency of IFN-alpha and loading capacity of the SLN were 83.7 +/- 4.5% and 1.73 +/- 0.15%, respectively. In vitro release study and antiviral assay demonstrated that the IFN-alpha released from the SLN in a 16-day period exhibited antiviral activity in Madin-Darby bovine kidney (MDBK) cells against vesicular stomatitis virus (VSV), and showed a release pattern of an initial burst release followed by a sustained and slow release. Cytotoxicity assay in cell culture demonstrated that the SLN were not toxic. The results of this exploratory study suggest that the IFN-alpha-loaded SLN could be a useful formulation for controlled release in veterinary therapeutics. (C) 2009 Elsevier Ltd. All rights reserved.