Objective: The steady-state pharmacokinetics of two doses of a transdermal testosterone cream (TTC) was investigated after daily application for 21 days.
Methods: This was a two-way cross-over study conducted for 6 weeks. Seven healthy postmenopausal women (mean age, 59.3 y) were randomly allocated to 5 or 10 mg of TTC applied daily to the upper arm. Serum total testosterone (TT), free testosterone (fT), sex hormone–binding globulin, and metabolite concentrations were measured. Baseline-corrected and uncorrected serum TT and fT pharmacokinetic parameters (AUC0-24, Cavg, Cmax, and Tmax) were calculated using a standard model-independent approach.
Results: After the single-dose application of 5 mg of TTC on day 22, the median uncorrected TT Cavg was found to be 0.54 ng/mL (range, 0.43-1.31), and the median uncorrected fT Cavg was found to be 4.14 pg/mL (range, 2.41-9.72). Doubling of the dose only resulted in a 30% increase in baseline-corrected TT Cavg (0.52 vs 0.69 ng/mL for 5 and 10 mg, respectively) and a 31% increase in baseline-corrected fT Cavg (4.75 vs 6.24 pg/mL for 5 and 10 mg, respectively). Neither dose resulted in any meaningful variation in dihydrotestosterone, estrone, estradiol, or sex hormone–binding globulin across the postdose sampling period.
Conclusions: The 5-mg TTC dose restores TT and fT levels to levels above and within the reference range, respectively, for premenopausal women.
From the 1Women’s Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia; and 2School of Pharmacy and Medical Sciences and 3Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
Received December 23, 2013; revised and accepted March 20, 2014.
Funding/support: Monash University sponsored the study. Lawley Pharmaceuticals (Subiaco, Western Australia, Australia) funded the cost of hormone quantification and provided the study drug. E.F. is a PhD student sponsored by the Iran Ministry of Health and Medical Education. S.E.R. is a National Health and Medical Research Council Australian clinical fellow (grant 1054946). S.R.D. is a National Health and Medical Research Council principal research fellow (grant 1041853).
Clinical trial registration: ACTRN12612001250820.
Financial disclosure/conflicts of interest: S.R.D. is presently an investigator for Trimel.
Address correspondence to: Susan R. Davis, MBBS, FRACP, PhD, Women’s Health Research Program, School of Public Health and Preventive Medicine, Monash University, The Alfred Center, Commercial Road, Melbourne, VIC 3004, Australia. E-mail: firstname.lastname@example.org