Investigation of the host-guest complexation between 4-sulfocalix[4]arene and nedaplatin for potential use in drug delivery

Abstract

Macromolecules including macrocyclic species have been reported to have the potential to encapsulate biologically active compounds such as drugs through host-guest complexation to increase their solubility, stability and bioavailability. In this paper the first experimental and theoretical investigation of the complexation between nedaplatin, a second generation antineoplastic drug, and p-4-sulfocalix[4]arene, a macromolecule possessing a bipolar amphiphilic structure with good biocompatibility and relatively low haemolytic toxicity for potential use as a drug delivery system is presented. Data from 1H NMR, UV, Job's plot analysis, HPLC and DFT calculations are detailed and suggest the formation of a 1:1 complex. The stability constant of the complex was experimentally estimated to be 3.6×104M−1 and 2.1×104M−1 which correspond to values of −6.2 and −5.9kcalmol−1, respectively for the free energy of complexation while the interaction free energy is calculated to be −4.9kcalmol−1. The formed species is shown to be stabilised in solution through hydrogen bonding between the host and the guest which may allow for this strategy to be effective for potential use in drug delivery.