The complexation of tetrahydroxycalix4arene-methyldimethylphosphine oxide (CMPO), tetrahydroxythiacalix4arene-methyldimethylphosphine oxide (TCMPO), and tetrapropoxycalix4arene-methyldiethylphosphine oxide (CEPO) with active pharmaceutical ingredients of antiviral drugs Remdesivir, Nevirapine, Vesatolimod, Bictegravir, Emtricitabine, and Tenofovir in the water medium was studied using the RP HPLC method. By analyzing the dependence of the drug capacity values on the concentration of calixarenes in the chromatographic mobile phase, the stability constants (KA = 1100 - 12000 M-1) of the complexes formed were determined. Quantum-chemical calculations show that the antiviral drugs form supramolecular exo-complexes with the calixarene-phosphine oxide molecules. These complexes can be stabilized by intermolecular hydrogen bonds between the proton acceptor P=O groups and the proton donor groups of antiviral drugs.
Kalchenko et al. (Tue,) studied this question.