The pharmacokinetics of dl- and l-moprolol in the human

The pharmacokinetics of a single dose (75 mg) of dl-moprolol and l-moprolol, a new beta -blocking agent, were appraised over 3 days in two groups of ten volunteers. The peak plasma level (GLC method) (598 +/- 99 ng/ml), the area under the curve (3.054 +/- 578 ng.ml/h), and 24-h urinary excretion (34.83 +/- 6.33 mg) after 1-moprolol intake were more elevated than after dl-moprolol intake. However, the plasma elimination half-life was not statistically different, 2.3 +/- 0.26 h after 1-moprolol versus 2.11 +/- 0.3 h after dl-moprolol. The double product (systolic blood pressure x heart rate) was significantly decreased only in volunteers after receiving 1-moprolol but not after dl-moprolol. The mean pharmacodynamic half-life estimated from exercise heart rate after dl-moprolol was 11.6 h.