New approach to improve encapsulation and antitumor activity of doxorubicin loaded in solid lipid nanoparticles

This work aimed to develop solid lipid nanoparticles (SLNs) loaded with doxorubicin evaluating the influence of docosahexaenoic acid (DHA), a polyunsaturated fatty acid that enhances the activity of anticancer drugs, on drug encapsulation efficiency (EE). The SLN were characterized for size, zeta potential, entrapment efficiency (EE) and drug release. Studies of in vitro antitumor activity and cellular uptake were also conducted. The reduction in particle size (from 127 +/- 14 to 94 +/- 1 nm) and negative charges were obtained for SLN loaded with DHA and triethanolamine (TEA), amine used to increase the solubility of doxorubicin in melted lipid. The EE was significantly improved from 36 +/- 4% to 99 +/- 2% for SLN without and with DHA at 0.4%, respectively. The doxorubicin release in a slightly acid medium (pH 5.0) was higher than that observed at physiological pH. The in vitro studies clearly showed the higher cytotoxicity of doxorubicin-DHA-loaded SLN than free doxorubicin + DHA on human lung tumor cell line (A549) and the improved cellular uptake achieved with the drug encapsulation can be an explanation. These findings suggest that DHA-doxorubicin-loaded SLN is a promising alternative for the treatment of cancer. (C) 2012 Elsevier B.V. All rights reserved.