Testosterone undecanoate

Ester hydrolysis does not invariably lead to inactive metabolites, as exemplified by acetylsalicylic acid. The cleavage product, salicylic acid, retains pharmacological activity. In certain cases, drugs are administered in the form of esters in order to facilitate absorption (enalapril enalaprilate testosterone undecanoate testosterone) or to reduce irritation of the gastrointestinal Lullmann, Color Atlas of Pharmacology... 

Testosterone propionate, though potent, has a short duration of action and is not practical for long-term use. Testosterone undecanoate can be given orally, administering large amounts of the steroid twice daily (eg, 40 mg/d) however, this is not recommended because oral... 

Hirsutism is common in patients taking androgens, and is often irreversible (62,63). In contrast, in women, loss of scalp hair can occur (64). Of 81 female-to-male transsexual subjects, mean age 37 years (range 21-61), treated with testosterone esters (n = 61 250 mg intramuscularly every 2 weeks) or testosterone undecanoate (n = 20 160-240 mg/day orally), 31 developed male-pattern baldness thinning of the hair was related to the duration of androgen administration and was present in about half of the transsexuals after 13 years (65). 

Testosterone is available as oral testosterone undecano-ate, buccal testosterone, intramuscular testosterone esters, testosterone implants, and testosterone transdermal patches and gel. Proponents of transdermal testosterone products, such as gels and scrotal or non-scrotal dermal patches, claim that they have a good safety profile (101). Transdermal testosterone replacement certainly improves bone mass and lean body mass, reduces fat mass, and improves mood and sexual function. There are said to be no harmful effects on the prostate and lipids. Acne, polycythemia, and gynecomastia are stated to be less common with this form of therapy than with the intramuscular esters. To date these claims must be regarded with some reservations it is not at all clear that in equieffective doses the local or topical forms of administration dissociate wanted and unwanted effects. 

Testosterone is used to treat various androgen deficiency syndromes. Following oral administration, free testosterone is effectively metabolized and inactivated in the liver before it reaches the systemic circulation [65], and unless very high doses are administered, no testosterone is detected in the plasma [66]. Testosterone undecanoate is a prodrug of testosterone esterified in the 17 3-position with undecanoic acid. Following oral administration, this prodrug is metabolized only partly in the intestinal wall [67], and the remaining fraction of... 

Nieschlag, E., et al. 1975. Plasma androgen levels in men after oral administration of testosterone or testosterone undecanoate. Acta Endocrinol (Copenh) 79 366. 

Horst, H.J., et al. 1976. Lymphatic absorption and metabolism of orally administered testosterone undecanoate in man. Klin Wochenschr 54 875. 

Tauber, U., et al. 1986. Absolute bioavailability of testosterone after oral administration of testosterone-undecanoate and testosterone. Eur J Drug Metab Pharmacokinet 11 145. 

Shackleford, D.M., et al. 2003. Contribution of lymphatically transported testosterone undecanoate to the systemic exposure of testosterone after oral administration of two andriol formulations in conscious lymph duct-cannulated dogs. J Pharmacol Exp Ther 306 925. 

De Ridder, J. J., and Koppens, P. C. (1978). Discrimination between endogenous and exogenous testosterone in human plasma after oral treatment with testosterone undecano-ate, using stable-isotope labeled compounds and mass spectrometric analysis. In Stable Isotopes. Applications in Pharmacology, Toxicology and Clinical Research (T. A. Baillie, ed.), pp. 157-165. Mcmillan, New York. 

Testosterone Undecanoate/ Restandol 40mg/Organon Laboratories/hormone replacement therapy... 

Oleic acid is the common name for (Z)-9-octadece-noic acid and is a nearly colorless liquid at room temperature with a melting point of 5-7°C. Oleic acid is practically insoluble in water but has been used as a solvent for oral delivery of hydrophobic drugs in soft gelatin capsules. Oleic acid is used to solubilize ritonavir in Norvir and Kaletra soft gelatin capsules (see section Microemulsion Oral Formulations ). Testosterone undecanoate is an ester prodrug of testosterone intended for oral administration in hormone replacement therapy, and is solubilized in oleic acid in 40 mg Restandol 40 mg soft gelatin capsules. 

Testosterone is available as oral testosterone undecano-ate, buccal testosterone, intramuscular testosterone esters, testosterone implants, and testosterone transder-mal patches and gel. 

Testosterone Undecanoate/ Restandol 40 mg/ Organon Laboratories/1981 CHjj H T ] Hormone replacement therapy 40-160 mg q.d. (1-4 capsules) Soft gelatin capsule 40 mg HSE (equivalents of testosterone, 61 mg of testosterone undecanoate Oleic acid Wholesaler in the refrigerator (2-8°C), and the patient at RT. Protect from light and heat. 

Oleic acid solubilizes 61 mg of testosterone undecanoate in Restandol 40 mg soft gelatin capsules. Testosterone undecanoate is an ester prodrug of testosterone intended for oral administration in hormone replacement therapy. Free testosterone is inactive following oral administration due to virtually complete hepatic first-pass extraction. However, the undecanoate ester prodrug is transported via the intestinal lymphatic system, thereby circumventing the hepatic portal circulation and the associated presystemic first-pass metabolism. The oral dose of testosterone undecanoate is 40-160 mg equivalents of testosterone (one to four capsules) once daily. Restandol 40 mg soft... 

Testosterone undecanoate Andriol 6 hours 10 hours 6 hours —... 

Testocaps is not approved for use in the United States) (Fig. 45.9) has been attributed to formation of testosterone via systemic ester hydrolysis of lymphatically transported testosterone undecanoate (72). Its oral bioavailability was approximately 3%. Lymphatically transported testosterone undecanoate accounted for between 90 and 100% of the systemically available ester and that 83 and 85% of the systemically available testosterone resulted from systemic hydrolysis of lymphatically transported testosterone undecanoate. These data demonstrate that intestinal lymphatic transport of testosterone undecanoate produces increased systemic exposure of testosterone by avoiding the extensive first-pass hepatic metabolism responsible for the inactivation of testosterone after oral administration. 

Yin A, Alfadhli E, Htun M, Dudley R, Faulkner S, Hull L et al. Dietary fat modulates the testosterone pharmacokinetics of a new self-emulsifying formulation of oral testosterone undecanoate in hypogo-nadalmen. JAndrol. 33(6) (2012) 1282-1290. 

Discrimination Between Endogenous and Exogenous Testosterone in Human Plasma After Oral Treatment with Testosterone Undecanoate Using Stable-Isotope-Labeling Compounds and Mass Spectrometrie Analysis Stable Isot., Proc. Int. Symp. 1977... 

Gas Chromatograpny-Mass Spectrometry Quantification Method for Simultaneous Determination of Endogenous and Exogenous Human Plasma Testosterone Levels After Treatment with Testosterone Undecanoate, A New Oral Active Testosterone Derivative Adv. Mass Spectrom. 78 1544-1550 (1978) CA 89 103061n... 

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