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Testosterone release from a subcutaneous, biodegradable microcapsule formulation (Viatrel) in hypogonadal men
John K Amory1, Brad D Anawalt, Phillip D Blaskovich
1Population Center for Research in Reproduction, Geriatric Research Education and Clinical Center, Veteran's Affairs Puget Sound Health Care System, Seattle, Washington, USA. jamory@u.washington.edu
Journal of Andrology
|January 10, 2002
Summary
Testosterone microcapsules offer a new long-term therapy for men with hypogonadism. A single injection normalized hormone levels for up to 10-11 weeks, showing promise for convenient testosterone replacement.
Area of Science:
- Endocrinology
- Pharmacology
- Drug Delivery Systems
Background:
- Male hypogonadism necessitates testosterone replacement therapy (TRT).
- Current TRT methods in the US include transdermal patches, topical gels, and intramuscular injections.
- Biodegradable polylactide-co-glycolide microcapsules are established for long-term drug delivery.
Purpose of the Study:
- To evaluate the pharmacokinetics and pharmacodynamics of testosterone release from microcapsules.
- To assess the efficacy and safety of testosterone microcapsules for treating hypogonadism.
Main Methods:
- An open-label, prospective study involving 14 men with hypogonadism.
- Single subcutaneous injection of either 267 mg or 534 mg of testosterone microcapsules.
- Monitoring of serum total testosterone, dihydrotestosterone, estradiol, SHBG, LH, and FSH levels over 8-12 weeks.
Main Results:
- Mean serum total testosterone peaked on day 1 post-injection, with higher levels in the 534 mg group (34.7 nmol/L).
- Hormone levels normalized for up to 42 days (267 mg group) and 70 days (534 mg group).
- No significant adverse reactions were observed, with only mild injection site tenderness reported.
Conclusions:
- A single 534 mg dose of testosterone microcapsules normalizes hormone levels in hypogonadal men for up to 10-11 weeks.
- Testosterone microcapsules represent a potentially safe and convenient option for long-term male hypogonadism treatment.
- This delivery system may also be suitable for male contraceptive regimens.
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