Bioavailability Study of Menorest®, a New Estrogen Transdermal Delivery System, Compared with a Transdermal Reservoir...

Area of Science:

• Endocrinology
• Pharmacokinetics
• Dermatology

Background:

• Hormone replacement therapy (HRT) is crucial for managing menopausal symptoms.
• Transdermal estradiol delivery systems aim to mimic physiological hormone profiles.
• Comparing novel delivery systems to established ones is essential for optimizing patient care.

Purpose of the Study:

• To compare the bioavailability and plasma profiles of estradiol and estrone from Menorest® versus Estraderm®.
• To evaluate the short-term safety and cutaneous tolerance of both estradiol transdermal systems.
• To assess if Menorest® provides more stable and physiological estradiol levels.

Main Methods:

• An open-label, randomized, crossover study involving 31 healthy postmenopausal women.
• Repeated application of Menorest® and Estraderm® for three 3.5-day periods (10.5 days total wear time per system).
• Measurement of plasma estradiol and estrone concentrations at steady-state over 106 hours, alongside assessment of local skin reactions.

Main Results:

• Both systems demonstrated similar overall bioavailability (AUC, Cav).
• Menorest® exhibited less fluctuating and more sustained plasma estradiol levels compared to Estraderm®.
• Menorest® showed a significantly lower incidence of local erythema (8.9% vs. 18.3%).

Conclusions:

• Menorest® provides a more consistent and sustained delivery of estradiol, approximating early to mid-follicular premenopausal levels.
• The new adhesive matrix system (Menorest®) offers improved cutaneous tolerance over the reference membrane/reservoir system (Estraderm®).
• Menorest® represents a potentially improved option for transdermal estradiol therapy with enhanced pharmacokinetic and safety profiles.