Solvents effect on the stability and reactivity of Tamoxifen and its nano metabolites as the breast anticancer drug

Abstract

The effect of protic and aprotic solvents polarity on optimized geometry and some chemical reactivity indices for Tamoxifen (TAM) and three of its important metabolites, i.e. 3-hydroxy Tamoxifen (3-HTAM), Droloxifen, 4-hydroxy Tamoxifen (4-HTAM), Afimoxifen, and Z-N-desmethyl-4-hydroxy Tamoxifen, Endoxifen (ENDX), antitumor are studied theoretically by density functional theory calculations (B3LYP) with 6-311++G(d, p) basis set in combination with polarizable continuum model (PCM) in selected non polar (CCl4), polar protic (H2O, Ethanol) and polar aprotic (DMSO, Acetone) solvents. The solvent-induced stretching vibrational frequency shifts (SFS) and the solvation influence on the DFT based chemical reactivity indices such as atomic charges, HOMO-LUMO energies, stabilization energies, variation of dipole moment of the conformers, ionization potential, electron affinity, chemical potential, hardness and softness have been investigated. The present results show the high kinetic stability and low chemical reactivity of Tam and its important active metabolite, Endoxifen, in water medium. So a drug carrier with good aqueous solubility should be applied to improve the bioavailability of these antitumor drugs.