A single intramuscular injection of testosterone buciclate has been found to produce physiological levels of testosterone within the normal range in hypogonadal men for 3 to 4 months.[3][1][8][9][2] The elimination half-life and mean residence time (average amount of time a single molecule of drug stays in the body) of testosterone buciclate were found to be 29.5 days and 60.0 days, respectively, whereas those of testosterone enanthate in castor oil were only 4.5 days and 8.5 days.[8][9][2] Testosterone buciclate also lasts longer than testosterone undecanoate, which has elimination half-lives and mean residence times of 20.9 days and 34.9 days in tea seed oil and 33.9 days and 36.0 days in castor oil, respectively.[1][9][2] In addition, there is a spike in testosterone levels with testosterone enanthate and testosterone undecanoate that is not seen with testosterone buciclate, with which levels stay highly uniform and decrease very gradually and progressively.[1] Testosterone buciclate can maintain testosterone levels in the normal male range for up to 20 weeks with a single intramuscular injection.[10]
Testosterone buciclate is able to reversibly and completely suppress spermatogenesis in men when used at sufficiently high dosages.[8] As such, the results of clinical studies for use of testosterone buciclate as a male contraceptive were promising, and trials continued as late as 1995,[11] but progress ultimately came to a standstill because the WHO was unable to find an industry partner willing to continue the development of the drug.[1] Because of this, the WHO backed away from testosterone buciclate and focused its research instead on testosterone undecanoate, which is also very long-lasting and has the advantage of having already been marketed and approved for medical use.[12]
Notes: Men produce about 3 to 11 mg of testosterone per day (mean 7 mg/day in young men). Footnotes:a = Never marketed. b = No longer used and/or no longer marketed. Sources: See template.
Note: All are via i.m. injection. Footnotes:a = TP, TV, and TUe. b = TP and TKL. c = TP, TPP, TiCa, and TD. d = Studied but never marketed. e = Developmental code names. Sources: See template.
^ abcdefNieschlag E, Behre HM, Engelmann U, Schwarzer U (29 June 2013). "Male Contrabution to Contraception". In Nieschlag E, Behre H (eds.). Andrology: Male Reproductive Health and Dysfunction. Springer Science & Business Media. pp. 316, 412. ISBN978-3-662-04491-9.
^ abcdeBehre HM, Abshagen K, Oettel M, Hübler D, Nieschlag E (May 1999). "Intramuscular injection of testosterone undecanoate for the treatment of male hypogonadism: phase I studies". European Journal of Endocrinology. 140 (5): 414–419. CiteSeerX10.1.1.503.1752. doi:10.1530/eje.0.1400414. PMID10229906. S2CID22597244.
^Behre HM, Nieschlag E (November 1992). "Testosterone buciclate (20 Aet-1) in hypogonadal men: pharmacokinetics and pharmacodynamics of the new long-acting androgen ester". The Journal of Clinical Endocrinology and Metabolism. 75 (5): 1204–1210. doi:10.1210/jcem.75.5.1430080. PMID1430080.
^Behre HM (13 February 1996). "Testosterone Buciclate". In Bhasin S (ed.). Pharmacology, Biology, and Clinical Applications of Androgens: Current Status and Future Prospects. John Wiley & Sons. pp. 472–. ISBN978-0-471-13320-9.
^Behre HM, Weinbauer GF, Nieschlag E (13 February 1996). "Testosterone Buciclate". In Bhasin S, Gabelnick HL, Spieler JM (eds.). Pharmacology, Biology, and Clinical Applications of Androgens: Current Status and Future Prospects. John Wiley & Sons. pp. 471–480. ISBN978-0-471-13320-9. Testosterone buciclate is applied intramuscularly as a microcrystalline aqueous suspension. [...] After air milling [...] of crystalline testosterone buciclate to a particle size of at least 75% in the range of 10 - 50 μm, the drug was [...] suspended in sterile, aqueous suspension vehicle [...].
^ abcNieschlag E, Behre HM (13 January 2010). "Testosterone Therapy". In Nieschlag E, Behre HM, Nieschlag S (eds.). Andrology: Male Reproductive Health and Dysfunction. Springer Science & Business Media. pp. 441–446. ISBN978-3-540-78355-8.
^Behre HM, Baus S, Kliesch S, Keck C, Simoni M, Nieschlag E (August 1995). "Potential of testosterone buciclate for male contraception: endocrine differences between responders and nonresponders". The Journal of Clinical Endocrinology and Metabolism. 80 (8): 2394–2403. doi:10.1210/jcem.80.8.7543113. PMID7543113.
^Nieschlag E, Kumar N, Sitruk-Ware R (March 2013). "7α-methyl-19-nortestosterone (MENTR): the population council's contribution to research on male contraception and treatment of hypogonadism". Contraception. 87 (3): 288–295. doi:10.1016/j.contraception.2012.08.036. PMID23063338.