ABSTRACT
Deflazacort (DFZ, a prodrug) is well absorbed and rapidly metabolized into the active metabolite 21-hydroxydeflazacort (21-OH DFZ) after oral administration. The aim of this study is to evaluate the pharmacokinetic properties of 21-OH DFZ in healthy Chinese volunteers after a single and multiple oral administration of DFZ tablets under fed condition. Twelve volunteers (six males and six females) were administered a single dose of 6 mg or 12 mg or 24 mg of DFZ in three different periods separately, according to the 3 x 3 Latin square design. Between each administration period there was a washout period of one week. The multiple-dose study of 12 mg dose DFZ per day for 7 consecutive days was started after a 1 w washout period when the single-dose study completed. The pharmacokinetic parameters of 21-OH DFZ after the single oral administration of 6 mg, 12 mg and 24 mg DFZ tablets were as follows: (37.7 +/- 11.6), (61.5 +/- 17.7) and (123 +/- 23) ng x mL(-1) for C(max); (1.90 +/- 0.32), (1.96 +/- 0.27) and (2.13 +/- 0.34) h for t1/2; (96.6 +/- 25.9), (190 +/- 44) and (422 +/- 107) ng x h x mL(-1) for AUC(0-14 h), respectively. After the multiple dose administration, the mean plasma concentration at steady-state C(av) was (7.00 +/- 1.66) ng x mL(-1) and the degree of plasma concentration fluctuation DF was 7.7 +/- 1.2. The results showed that the pharmacokinetic characteristics of 21-OH DFZ in healthy Chinese volunteers were linear over the dose range of 6 to 24 mg. No significant gender differences were found in the pharmacokinetics of 21-OH DFZ in healthy Chinese volunteers. After the multiple dose administration of 12 mg DFZ for 7 d, no accumulation of 21-OH DFZ in healthy Chinese volunteers was observed.