Additional Research Compound · For laboratory research use only
Also known as PSK-3841, HMR-3841
RU58841 (also written RU 58841, and catalogued as PSK-3841 or HMR-3841) is a non-steroidal androgen receptor antagonist of the N-substituted aryl hydantoin class, synthesised at the Roussel Uclaf research centre and first described in 1994 as a locally acting antiandrogen1,2. Chemically it is 4-[3-(4-hydroxybutyl)-4,4-dimethyl-2,5-dioxoimidazolidin-1-yl]-2-(trifluoromethyl)benzonitrile.
Published work is predominantly preclinical and dates mostly from the 1990s. Studies have examined receptor binding and androgen-dependent organs in hamsters and rats, sebaceous gland models, an androgen receptor reporter assay in prostate cells, a stumptailed macaque model of androgenetic alopecia and human balding scalp grafts maintained on nude mice1,3,4,5,6. Later work addressed prodrug and nanoparticle formulation for follicular targeting, and metabolite identification for doping control7,8.
As described in the research literature
As described in the research literature, RU58841 binds the androgen receptor with high affinity, as measured in hamster prostate and flank organ receptor preparations1. In PC3 prostate cells co-transfected with wild-type androgen receptor and an androgen-responsive reporter, it competitively suppressed dihydrotestosterone activation of the receptor, with a potency the authors described as comparable to hydroxyflutamide, and did not itself activate the receptor6.
Its local rather than systemic profile in animal models has been linked to its metabolism. In rat plasma, RU58841 was cleared relatively rapidly and was converted only to a small extent into the N-desalkyl metabolite RU 56279, which is itself antiandrogenic and eliminated more slowly; the authors related the low systemic activity of RU58841 to this low rate of conversion2. An ester prodrug, RU 58841-myristate, was shown to have little affinity for the receptor itself but to be converted to RU58841 by cultured skin fibroblasts, keratinocytes, dermal papilla cells and sebocytes7.
What published studies have examined
The originating study measured receptor affinity in hamster prostate and flank organ preparations and measured flank organ area, accessory sex organs and testosterone levels1. Reporter assays in PC3 cells compared RU58841 with hydroxyflutamide, bicalutamide and genistein for effects on dihydrotestosterone-driven receptor activity6.
The Syrian hamster ear sebaceous gland model was used to compare RU58841 with related non-steroidal antiandrogens and cyproterone acetate, including reversibility after exposure stopped and the contralateral ear as a check for systemic effects3. In the androgen-dependent fuzzy rat model, sebaceous lobule and duct size, BrdU-labelled cells, serum androgens and prostate weight were compared with castration, finasteride and a type I 5-alpha-reductase inhibitor4.
The bald scalp of stumptailed macaques was studied, a primate model of androgenetic alopecia, with hair density, thickness and length as measures6. A controlled study used balding human scalp grafts maintained on testosterone-conditioned nude mice to examine follicle recycling and linear hair growth rate over six months5.
Plasma pharmacokinetics and metabolic profiles were characterised in rats, identifying RU 56279 as the common N-desalkyl metabolite2. Formulation work loaded the myristate prodrug onto solid lipid nanoparticles and examined skin permeation in Franz cells and follicular targeting in porcine and human skin preparations7. A 2026 doping-control study identified candidate metabolites in vitro by liquid chromatography-high resolution mass spectrometry, and was designed to characterise urinary metabolites, systemic exposure and steroid profile parameters after a single topical application in a small volunteer group8.
RU 58841, a new specific topical antiandrogen: a candidate of choice for the treatment of acne, androgenetic alopecia and hirsutism.
Battmann T, Bonfils A, Branche C, et al. The Journal of Steroid Biochemistry and Molecular Biology, 1994.
Preliminary pharmacokinetics and metabolism of novel non-steroidal antiandrogens in the rat: relation of their systemic activity to the formation of a common metabolite.
Cousty-Berlin D, Bergaud B, Bruyant MC, et al. The Journal of Steroid Biochemistry and Molecular Biology, 1994.
Local inhibition of sebaceous gland growth by topically applied RU 58841.
Matias JR, Gaillard M Annals of the New York Academy of Sciences, 1995.
Effects of topical antiandrogen and 5-alpha-reductase inhibitors on sebaceous glands in male fuzzy rats.
Ye F, Imamura K, Imanishi N, et al. Skin Pharmacology, 1997.
A controlled study of the effects of RU58841, a non-steroidal antiandrogen, on human hair production by balding scalp grafts maintained on testosterone-conditioned nude mice.
De Brouwer B, Tételin C, Leroy T, et al. The British Journal of Dermatology, 1997.
Evaluation of RU58841 as an anti-androgen in prostate PC3 cells and a topical anti-alopecia agent in the bald scalp of stumptailed macaques.
Pan HJ, Wilding G, Uno H, et al. Endocrine, 1998.
RU 58841-myristate--prodrug development for topical treatment of acne and androgenetic alopecia.
Münster U, Nakamura C, Haberland A, et al. Die Pharmazie, 2005.
Investigation Into the Metabolism and Elimination Behavior of RU 58841, and Its Influence on the Steroid Profile in Humans.
Okutan A, Krug O, Fußhöller G, et al. Biomedical Chromatography, 2026.
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