Nanobiohybrids as delivery vehicles for camptothecin

A novel method of delivering non-ionic, poorly water-soluble drugs such as campthothecin was developed. Camptothecin was first incorporated into micelles derived from negatively charged surfactants. The negatively charged micelles were then encapsulated in nanoparticles of magnesium-aluminum layered double hydroxides (LDHs) by an ion exchange process. The resulting nanobiohybrids released camptothecin rapidly with complete release within 10 min at both pH 4.8 and 7.2. The LDH complex with carmine released carmine within 30 min at pH 4.8, but took over 70 days at pH 7.2. When administered to Glioma cells in vitro, the nanobiohybrid containing camptothecin resulted in significantly lower survival times compared to untreated cells, or to cells incubated with the surfactant, the pristine LDH, or water (delivery medium). The encapsulation method allowed for an approximately threefold increase in solubility of camptothecin. In addition, the modification of the surface of the LDH provided potential site-directing of the nanohybrids. These enhancements to the delivery scheme suggest the potential use of these hybrids for a variety of drug therapies. (C) 2004 Elsevier B.V All rights reserved.