Catanionic vesicles from an amphiphilic prodrug molecule: a new concept for drug delivery systems

Abstract

Toxicity and low entrapment efficiency are the main problems for pharmaceutical applications of catanionic vesicles. In order to minimize surfactant toxicity, increase the drug loading content and simultaneously reduce the need for tedious chemical synthesis, we use oleic acid as the biocompatible surfactant, which reacts with the selected drug molecules (amlodipine) to produce an amphiphilic prodrug molecule for the straightforward fabrication of catanionic vesicles. The prodrug molecules are easily obtained by proton transfer between amlodipine and oleic acid molecules. The characterization of prodrug molecules and their aggregation behaviours in aqueous solutions are investigated by using Fourier transform infrared spectrophotometry (FTIR), 1H-nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC), surface tension measurement, transmission electron microscopy (TEM), dynamic light scattering (DLS), conductivity and zeta potential (ζ). The results demonstrate that vesicles could be easily formed with the prodrug amphiphilic molecules dispersed in aqueous solutions. Particularly, the drug release behaviour of the as-prepared catanionic vesicles exhibits excellent sustained drug release properties, which demonstrates their promising application in the newly designed drug delivery system.