Testosterone buciclate (developmental code names 20 Aet-1, CDB-1781) is a

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

, injected

anabolic–androgenic steroid Anabolic steroids, also known as anabolic-androgenic steroids (AAS), are a class of drugs that are structurally related to testosterone, the main male sex hormone, and produce effects by binding to the androgen receptor (AR). Anabolism, Anaboli ...

(AAS) which was never marketed. It was developed in collaboration by the Contraceptive Development Branch (CDB) of the

National Institute of Child Health and Human Development The ''Eunice Kennedy Shriver'' National Institute of Child Health and Human Development (NICHD) is one of the National Institutes of Health (NIH) in the United States Department of Health and Human Services. It supports and conducts research ai ...

(NICHD) and the

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

(WHO) in the 1970s and early 1980s for use in

androgen replacement therapy Androgen replacement therapy (ART), often referred to as testosterone replacement therapy (TRT), is a form of hormone therapy in which androgens, often testosterone, are supplemented or replaced. It typically involves the administration of tes ...

for male

hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...

and as a potential

male contraceptive Male contraceptives, also known as male birth control, are methods of preventing pregnancy by interrupting the function of sperm. The main forms of male Birth control, contraception available today are condoms, vasectomy, and Coitus interruptus, w ...

. It was first described in 1986. The medication is an

androgen ester An androgen or anabolic steroid ester is an ester of an androgen/anabolic steroid (AAS) such as the natural testosterone or dihydrotestosterone (DHT) or the synthetic nandrolone (19-nortestosterone). Esterification renders AAS into metabolism-res ...

– specifically, the C17β buciclate (4-butylcyclohexane-1-carboxylate)

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...

– and is a

prodrug A prodrug is a pharmacologically inactive medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be ...

of testosterone with a very long

duration of action Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms (fo ...

when used as a

depot Depot may refer to: Places * Depot, Poland, a village * Depot Glacier (disambiguation) * Depot Island (disambiguation) * Depot Nunatak * Depot Peak Brands and enterprises * Maxwell Street Depot, a restaurant in Chicago, United States * Of ...

via

intramuscular injection Intramuscular injection, often abbreviated IM, is the medical injection, injection of a substance into a muscle. In medicine, it is one of several methods for parenteral, parenteral administration of medications. Intramuscular injection may be ...

. Testosterone buciclate is formulated as a

microcrystalline A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but ...

aqueous suspension with a defined

particle size Particle size is a notion introduced for comparing dimensions of solid particles ('' flecks''), liquid particles ('' droplets''), or gaseous particles ('' bubbles''). The notion of particle size applies to particles in colloids, in ecology, in ...

of at least 75% in the range of 10 to 50 μm. A single intramuscular injection of testosterone buciclate has been found to produce

physiological Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

levels of testosterone within the normal range in hypogonadal men for 3 to 4 months. The

elimination half-life Biological half-life (elimination half-life, pharmacological half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the blood plasma. ...

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 Testosterone enanthate is used in the treatment of low testosterone levels in men. It is also used in hormone therapy for women and transgender men. It is given by injection into muscle or subcutaneously usually once every one to four weeks. ...

castor oil Castor oil is a vegetable oil pressed from castor beans, the seeds of the plant ''Ricinus communis''. The seeds are 40 to 60 percent oil. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is and its den ...

were only 4.5 days and 8.5 days. Testosterone buciclate also lasts longer than

testosterone undecanoate Testosterone undecanoate, sold under the brand name Nebido among others, is an androgen and anabolic steroid (AAS) medication that is used mainly in the treatment of low testosterone levels in men, It is taken by mouth or given by injection ...

, which has elimination half-lives and mean residence times of 20.9 days and 34.9 days in

tea seed oil Tea seed oil (also known as ''camellia oil'', ''camellia seed oil'', ''teanut oil'') is an edible plant oil. It is obtained from the seeds of '' Camellia oleifera''. ''Camellia sasanqua'' is also given as a source of 'tea seed oil. Description ...

and 33.9 days and 36.0 days in castor oil, respectively. 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. Testosterone buciclate can maintain testosterone levels in the normal male range for up to 20 weeks with a single intramuscular injection. Testosterone buciclate is able to reversibly and completely suppress

spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testicle. This process starts with the Mitosis, mitotic division of the stem cells located close to the basement membrane of ...

in men when used at sufficiently high dosages. 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, 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. 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.

References

{{Estrogen receptor modulators Abandoned drugs Anabolic–androgenic steroids Androstanes Buciclate esters Contraception for males Ketones Testosterone esters

See also

References