A first estimation of the thermodynamic parameters of water/n-octanol partitioning of some tricyclic antidepressants: Similarities and differences with the values of other psychotropic drugs

Abstract

Thermometric titrimetry allows the determination of the thermodynamic parameters of transfer from water to n-octanol for tricyclic antidepressants. Their transfers are both entropy and enthalpy driven, whereas those of phenothiazinic neuroleptics are solely entropy driven. The hypothesis of the folding of the lateral chain upon the tricyclic nucleus in antidepressive drugs gives a satisfactory explanation of the results. Differences and analogies of behavior during the partitioning of antidepressants and phenothiazinic compounds are also underlined.