Nanostructures from alkyl vitamin C derivatives (ASCn):: Properties and potential platform for drug delivery

Alkyl vitamin C derivatives (ASC(n)) combine in their structure a lipophilic and a hydrophilic moiety and exhibit proper-ties of typical surfactant molecules. Self-assembly properties of ASC(n) depend on the length of n-alkyl fatty chain. ASC(n) start to aggregate at temperatures (CMT, Krafft point) in which the solubility reaches the critical micellar concentration (CMC). Above this temperature, ASC(n) can aggregate in micelles or gel phase, depending of alkyl side chain. Upon cooling, for less soluble derivatives (ASC(12), ASC(14) and ASC(16)) liquid-crystal structures named coagels are obtained. They are able to solubilized insoluble and unstable drugs, protect them from any possible aggressive environment and promote their permeation through skin. Besides, the rheological properties of the coagels would be adequate for topical administration of pharmaceutical. These systems possess very interesting properties making ASC(n), coagels promising pharmaceutical platforms for drug delivery. Results from investigations about all these properties are described and analyzed. Also, the perspectives of these systems as drug delivery systems are discussed. (c) 2007 Elsevier B.V. All rights reserved.