 Pharmacokinetic study of transdermal E2 in Turner syndrome teens showed absorption of E2 by first order kinetics 9. Steady state was achieved approximately 9 hrs after application of a 37.5 μg patch, and serum concentrations reached a mean of 52.9 17.8 SD pgml. This demonstrates a rise in plasma estradiol of about 1 pgml 3.67 pmoll for every 1.0 μg applied to the skin, similar to package insert data in adults. This would suggest that a starting dose of 5-10 ug transdermal E2 daily approximates the 133-266 μg monthly amount of E2 delivered by the 0.2-0.4 mg monthly injections of E2 cypionate. 