Quantitative structure-property relationships (QSPR) for steroidal compounds of environmental importance

A quantitative structure-property relationships (QSPR) study was carried out for 17 steroidal compounds using calculated molecular descriptors and measured properties. The utility of calculated molecular descriptors and properties was evaluated and improved in some instances by subgroup classification of these 17 compounds into estrogens and androgens. The calculated values for the octanol-water partition coefficient (logK(ow)) were found to be in good agreement with the measured values for all 17 compounds, whilst good agreement between the calculated and measured values for aqueous solubility (logS) was found only for the subgroup of androgens. Good linear relationships (R(2)0.782) were found between measured logK(ow) values and three molecular descriptors (logFOSA, hydrophobic component of the total solvent accessible surface area; logFISA, hydrophilic component of the total solvent accessible area and logPSA, Van de Waals surface area of polar nitrogen and oxygen atoms). For the measured logS values, only weak correlations with molecular descriptors were observed (R(2)0.505). The coefficient of logS in the relationship with the hydrophobic parameter (logFOSA) was negative but positive with the hydrophilic parameters (logFISA and logPSA). Conversely with logK(ow) the opposite was found. These observations are in accord with the effects of molecular polarity on aqueous solubility.