Synthetic progestin drospirenone was assessed as single compound and in mixtures.
Mixtures of drospirenone with P4 and estrogen were assessed in vitro and in vivo.
Mixture activities in vitro were mostly additive.
Mixture activities in zebrafish eleuthero-embryos were more complex.
Equi-effective mixtures of DRS and EE2 showed antagonistic interactions in vivo.