Abstract
Nine patients taking oral doses of 10 mg/12 h rac‐pindolol as part of their treatment for hypertension in pregnancy were recruited for the study. Maternal and fetal gestational age ranged from 20–38 years and 28–41 weeks, respectively. Blood was collected from the umbilical cord vein and from the mother from zero to 12 h after drug administration. Urine was collected for 12 h after rac‐pindolol administration at the following intervals: 0–3, 3–6, 6–9, and 9–12 h. Plasma and urine concentrations of the pindolol enantiomers were determined by HPLC using a Chiralpak® AD chiral column and fluorescence detection. The data were fitted to a one‐compartment model and differences between (+)‐R and (−)‐S enantiomers were compared by the paired t‐test (P < 0.05). Mean results are reported. The disposition of pindolol in maternal plasma was stereoselective, with higher AUC (84.34 vs. 95.69 ng.h/ml) and Cl~R~ values (9.16 vs. 10.85 L/h) and lower Vd/f (251.38 vs. 225.17 L) and Cl/f (62.48 vs. 55.74 L/h) for the (+)‐R pindolol. The transplacental distribution of pindolol was not stereoselective. Cord, plasma, and presumably fetal, concentrations of the pindolol enantiomers were 56% of the maternal plasma concentrations up to 6 h after the last dose. Chirality 14:683–687, 2002. © 2002 Wiley‐Liss, Inc.