A modular approach towards drug delivery vehicles using oxanorbornane-based non-ionic amphiphiles

The self-assembly of non-ionic amphiphiles with a hydroxylated oxanorbornane head-group was controlled using amino acid units as spacers between hydrophilic and lipophilic domains to get spherical supramolecular aggregates. The ability of these systems to harbour therapeutic agents like ibuprofen, and their drug-release profiles were evaluated. Apart from directing the assembly, the intervening amino acid unit was found to help in drug entrapment as well. The presence of cholesterol improved their drug-loading ability, and an encapsulation efficiency of up to 66% was shown by the formulation containing the phenylalanine residue as the spacer (NC1c). There was no burst release, and 45% drug release was observed at the end of 24 h in this case (cf. soyaphosphatidylcholine based formulation = 49%). The results from SEM, Cryo-TEM, PXRD and confocal microscopic studies with some insights into molecular packing in this class of aggregates are also included.