Testosterone buciclate

Testosterone buciclate
Clinical data
Other namesTestosterone bucyclate; Testosterone 17β-buciclate; 20 Aet-1; CDB-1781; Testosterone 17β-(trans-4-butylcyclohexyl)carboxylate
Routes of
administration		Intramuscular injection
Drug classAndrogen; Anabolic steroid; Androgen ester
Pharmacokinetic data
BioavailabilityOral: very low
Intramuscular: very high
MetabolismLiver
Elimination half-lifeTea seed oil: 20.9 days (i.m.Tooltip intramuscular injection)[1][2]
Castor oil: 33.9 days (i.m.)[1][2]
ExcretionUrine
Identifiers
  • [(8R,9S,10R,13S,14S,17S)-10,13-dimethyl-3-oxo-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl] 4-butylcyclohexane-1-carboxylate
CAS Number
PubChem CID
ChemSpider
UNII
CompTox Dashboard (EPA)
Chemical and physical data
FormulaC30H46O3
Molar mass454.695 g·mol−1
3D model (JSmol)
  • CCCCC1CCC(CC1)C(=O)O[C@H]2CC[C@@H]3[C@@]2(CC[C@H]4[C@H]3CCC5=CC(=O)CC[C@]45C)C
  • InChI=1S/C30H46O3/c1-4-5-6-20-7-9-21(10-8-20)28(32)33-27-14-13-25-24-12-11-22-19-23(31)15-17-29(22,2)26(24)16-18-30(25,27)3/h19-21,24-27H,4-18H2,1-3H3/t20?,21?,24-,25-,26-,27-,29-,30-/m0/s1
  • Key:ODZDZTOROXGJAV-IRWJKHRASA-N

Testosterone buciclate (developmental code names 20 Aet-1, CDB-1781) is a synthetic, injected anabolic–androgenic steroid (AAS) which was never marketed.[3][4][5] It was developed in collaboration by the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development (NICHD) and the World Health Organization (WHO) in the 1970s and early 1980s for use in androgen replacement therapy for male hypogonadism and as a potential male contraceptive.[3] It was first described in 1986.[4] The medication is an androgen ester – specifically, the C17β buciclate (4-butylcyclohexane-1-carboxylate) ester of testosterone – and is a prodrug of testosterone with a very long duration of action when used as a depot via intramuscular injection.[3][6] Testosterone buciclate is formulated as a microcrystalline aqueous suspension with a defined particle size of at least 75% in the range of 10 to 50 μm.[7]

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]

Androgen replacement therapy formulations and dosages used in men
Route Medication Major brand names Form Dosage
Oral Testosteronea – Tablet 400–800 mg/day (in divided doses)
Testosterone undecanoate Andriol, Jatenzo Capsule 40–80 mg/2–4× day (with meals)
Methyltestosteroneb Android, Metandren, Testred Tablet 10–50 mg/day
Fluoxymesteroneb Halotestin, Ora-Testryl, Ultandren Tablet 5–20 mg/day
Metandienoneb Dianabol Tablet 5–15 mg/day
Mesteroloneb Proviron Tablet 25–150 mg/day
Sublingual Testosteroneb Testoral Tablet 5–10 mg 1–4×/day
Methyltestosteroneb Metandren, Oreton Methyl Tablet 10–30 mg/day
Buccal Testosterone Striant Tablet 30 mg 2×/day
Methyltestosteroneb Metandren, Oreton Methyl Tablet 5–25 mg/day
Transdermal Testosterone AndroGel, Testim, TestoGel Gel 25–125 mg/day
Androderm, AndroPatch, TestoPatch Non-scrotal patch 2.5–15 mg/day
Testoderm Scrotal patch 4–6 mg/day
Axiron Axillary solution 30–120 mg/day
Androstanolone (DHT) Andractim Gel 100–250 mg/day
Rectal Testosterone Rektandron, Testosteronb Suppository 40 mg 2–3×/day
Injection (IMTooltip intramuscular injection or SCTooltip subcutaneous injection) Testosterone Andronaq, Sterotate, Virosterone Aqueous suspension 10–50 mg 2–3×/week
Testosterone propionateb Testoviron Oil solution 10–50 mg 2–3×/week
Testosterone enanthate Delatestryl Oil solution 50–250 mg 1x/1–4 weeks
Xyosted Auto-injector 50–100 mg 1×/week
Testosterone cypionate Depo-Testosterone Oil solution 50–250 mg 1x/1–4 weeks
Testosterone isobutyrate Agovirin Depot Aqueous suspension 50–100 mg 1x/1–2 weeks
Testosterone phenylacetateb Perandren, Androject Oil solution 50–200 mg 1×/3–5 weeks
Mixed testosterone esters Sustanon 100, Sustanon 250 Oil solution 50–250 mg 1×/2–4 weeks
Testosterone undecanoate Aveed, Nebido Oil solution 750–1,000 mg 1×/10–14 weeks
Testosterone buciclatea – Aqueous suspension 600–1,000 mg 1×/12–20 weeks
Implant Testosterone Testopel Pellet 150–1,200 mg/3–6 months
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.
Pharmacokinetics of testosterone esters
Testosterone ester Form Route TmaxTooltip Time to peak levels t1/2Tooltip Elimination half-life MRTTooltip Mean residence time
Testosterone undecanoate Oil-filled capsules Oral ? 1.6 hours 3.7 hours
Testosterone propionate Oil solution Intramuscular injection ? 0.8 days 1.5 days
Testosterone enanthate Castor oil solution Intramuscular injection 10 days 4.5 days 8.5 days
Testosterone undecanoate Tea seed oil solution Intramuscular injection 13.0 days 20.9 days 34.9 days
Testosterone undecanoate Castor oil solution Intramuscular injection 11.4 days 33.9 days 36.0 days
Testosterone buciclatea Aqueous suspension Intramuscular injection 25.8 days 29.5 days 60.0 days
Notes: Testosterone cypionate has similar pharmacokinetics to Testosterone enanthate. Footnotes: a = Never marketed. Sources: See template.
Parenteral durations of androgens/anabolic steroids
Medication Form Major brand names Duration
Testosterone Aqueous suspension Andronaq, Sterotate, Virosterone 2–3 days
Testosterone propionate Oil solution Androteston, Perandren, Testoviron 3–4 days
Testosterone phenylpropionate Oil solution Testolent 8 days
Testosterone isobutyrate Aqueous suspension Agovirin Depot, Perandren M 14 days
Mixed testosterone estersa Oil solution Triolandren 10–20 days
Mixed testosterone estersb Oil solution Testosid Depot 14–20 days
Testosterone enanthate Oil solution Delatestryl 14–28 days
Testosterone cypionate Oil solution Depovirin 14–28 days
Mixed testosterone estersc Oil solution Sustanon 250 28 days
Testosterone undecanoate Oil solution Aveed, Nebido 100 days
Testosterone buciclated Aqueous suspension 20 Aet-1, CDB-1781e 90–120 days
Nandrolone phenylpropionate Oil solution Durabolin 10 days
Nandrolone decanoate Oil solution Deca Durabolin 21–28 days
Methandriol Aqueous suspension Notandron, Protandren 8 days
Methandriol bisenanthoyl acetate Oil solution Notandron Depot 16 days
Metenolone acetate Oil solution Primobolan 3 days
Metenolone enanthate Oil solution Primobolan Depot 14 days
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.
Structural properties of major testosterone esters
Androgen Structure Ester Relative
mol. weight		 Relative
T contentb		 logPc
Position(s) Moiet(ies) Type Lengtha
Testosterone – – – – 1.00 1.00 3.0–3.4
Testosterone propionate C17β Propanoic acid Straight-chain fatty acid 3 1.19 0.84 3.7–4.9
Testosterone isobutyrate C17β Isobutyric acid Branched-chain fatty acid – (~3) 1.24 0.80 4.9–5.3
Testosterone isocaproate C17β Isohexanoic acid Branched-chain fatty acid – (~5) 1.34 0.75 4.4–6.3
Testosterone caproate C17β Hexanoic acid Straight-chain fatty acid 6 1.35 0.75 5.8–6.5
Testosterone phenylpropionate C17β Phenylpropanoic acid Aromatic fatty acid – (~6) 1.46 0.69 5.8–6.5
Testosterone cypionate C17β Cyclopentylpropanoic acid Cyclic carboxylic acid – (~6) 1.43 0.70 5.1–7.0
Testosterone enanthate C17β Heptanoic acid Straight-chain fatty acid 7 1.39 0.72 3.6–7.0
Testosterone decanoate C17β Decanoic acid Straight-chain fatty acid 10 1.53 0.65 6.3–8.6
Testosterone undecanoate C17β Undecanoic acid Straight-chain fatty acid 11 1.58 0.63 6.7–9.2
Testosterone buciclated C17β Bucyclic acide Cyclic carboxylic acid – (~9) 1.58 0.63 7.9–8.5
Footnotes: a = Length of ester in carbon atoms for straight-chain fatty acids or approximate length of ester in carbon atoms for aromatic or cyclic fatty acids. b = Relative testosterone content by weight (i.e., relative androgenic/anabolic potency). c = Experimental or predicted octanol/water partition coefficient (i.e., lipophilicity/hydrophobicity). Retrieved from PubChem, ChemSpider, and DrugBank. d = Never marketed. e = Bucyclic acid = trans-4-Butylcyclohexane-1-carboxylic acid. Sources: See individual articles.
  1. ^ a b c d e f Nieschlag 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. ISBN 978-3-662-04491-9.
  2. ^ a b c d e Behre 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. CiteSeerX 10.1.1.503.1752. doi:10.1530/eje.0.1400414. PMID 10229906. S2CID 22597244.
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  7. ^ 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. ISBN 978-0-471-13320-9. 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 [...].
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