Effects of vehicle supplementation on total estradiol absorption from a transdermal estradiol delivery system.

OBJECTIVE

To evaluate the effects of vehicle supplementation on serum estradiol (E2) delivery pharmacokinetics from the Ciba-Geigy (Summit, NJ) 0.1-mg Estraderm Patch.

DESIGN

Postmenopausal women were randomized to a 28-day crossover treatment protocol separated by a 14-day wash out period.

SETTING

Normal human volunteers were studied in an academic research environment.

PATIENTS, PARTICIPANTS: The subject pool included eight healthy postmenopausal women between 32 and 60 years of age.

INTERVENTIONS

In treatment A, a 0.1-mg Estraderm Patch was worn for 7 days; in treatment B, and identical patch was worn into which 0.6 mL of ethanol was injected on day 3 of use.

MAIN OUTCOME MEASURES

Serum E2 levels were measured in both groups.

RESULTS

Although E2 absorption showed characteristic interpatient variability, addition of ethanol significantly extended the mean time for serum E2 levels to return to baseline, without increasing peak absorption. The mean extension was 50 hours.

CONCLUSION

The addition of ethanol to the Estraderm Patch increased the duration of elevated serum E2 levels measured in menopausal women, thus potentially increasing the effective life span of the transdermal therapeutic system.