following a single oral dose of 100 mg all-trans- or 13-cis-retinoic acid per kg body wt , concentrations of the parent drugs , of the c-13 isomerization products , as well as of their 4-oxo metabolites were determined in maternal plasma and embryo at two sensitive stages of organogenesis , i.e. , days 9 or 11 of gestation .
C0022265
13-cis-retinoic
C0032961
gestation