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A randomized, sequential, bioreplication study was performed with 24 healthy volunteers to assess the pharmacokinetic variability of oral and intravenous administrations of valspodar, a multidrug resistance modulator for use as a chemotherapy adjunct. Subjects received 200 mg as a 2-hour intravenous infusion and 400 mg orally as microemulsion soft gelatin capsules each given on two separate occasions. Following replicate intravenous administrations, reproducibility in peak concentration and area-under-the-curve was demonstrated by interoccasion equivalence testing. Low to moderate inter- and intra-subject pharmacokinetic variability were observed with coefficients of variation ranged from 9% to 19%. Absolute bioavailability from the microemulsion formulation was 60%. Replicate oral administrations demonstrated uniform and repeatable absorption with interoccasion equivalence in peak concentration, time to reach the peak concentration, and area-under-the-curve. Coefficients of inter- and intra-subject variation for these parameters ranged from 10% to 20% indicating low to moderate pharmacokinetic variability. When variabilities were compared between the two routes of administration, the absence of differences indicated that the rate and extent of drug absorption from the microemulsion formulation was as uniform and repeatable as by intravenous infusion.

Objective: To investigate the effects of tibolone on carbohydrate metabolism, and to compare these effects with those of a sequential regimen of conjugated equine estrogens and medrogestone. Methods: This was an open-label, multicentre, comparative study. Seventy-two postmenopausal women were randomized to receive either tibolone 2.5 mg/day or conjugated equine estrogens 0.6 mg plus sequential medrogestone 5 mg (CEE/M) for six 28-day cycles. Carbohydrate metabolism was evaluated at baseline and after three and six cycles of treatment by an oral glucose tolerance test (OGTT). A blood sample was taken at 30, 60, 90 and 120 mm after glucose 75 mg dosing for determination of plasma glucose, insulin and connecting peptide (C-peptide) levels. Results: The changes from baseline of glucose, insulin and C-peptide area-under-the-curve (AUC) values were not statistically significant after 3 and 6 months of tibolone or CEE/M treatment. There was a small transitory decrease in HbA 1C after three cycles of treatment with tibolone. Conclusion: The effects of tibolone and CEE/M on carbohydrate metabolism were considered to have no clinical significance.