Bioavailability of beta-acetyldigoxin after single and repeated doses of tablets and solution

In eight healthy volunteers the bioavailability of beta-acetyldigoxin solution and tablets was measured after single and multiple doses. Plasma and urine data were used to calculate bioavailability by four different methods. The differences obtained and the interindividual variations suggested that different and independent methods should be employed to assess "absolute" and "true" bioavailability. There was no significant difference between the regimens and both preparations had similar bioavailability; mean values (+/- SD) for the solution were 68.3 +/- 8.7% (single dose) and 68.6 +/- 5.9% (multiple doses), and for the tablets 72.8 +/- 7.5% and 66.1 +/- 6.0%, respectively. For routine measurements, single dose studies with plasma and urine sampling for 24 hours and 48 hours, respectively were an accurate and practicable procedure.