Purpose: The aim of this study was to investigate the sex-dependent difference in P-glycoprotein activity as measured by the probe drug talinolol.
Methods: A randomized, single-blind, parallel study was carried out in 20 healthy male and 20 healthy female volunteers. The pharmacokinetics of talinolol were measured after single oral dosing of 50-mg tablet and the pharmacokinetic parameters for male and female subjects were compared after excluding the potential influence of P-gp genetic polymorphisms.
Results: Talinolol AUC(0-48h) in the female subjects was 23.5% (p = 0.003) higher than that of male subjects. There was no significant sex difference in weight-corrected oral clearance, AUC, or other PK parameters.
Conclusion: The AUC and other PK data of talinolol, corrected for body weight, did not differ between genders after oral administration. The observed sex difference in talinolol systemic exposure is of little clinical relevance. The overall activity of P-gp shows no sex-related difference.