Chemistry:18-Methylsegesterone acetate
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| Other names | 18-Methyl-SGA; 13β-Ethyl-SGA; 18-Methylnestorone; 18-Methyl-NES; 13β-Ethylnestorone; 13β-Ethyl-NES; 18-Methylelcometrine; 16-Methylene-17α-acetoxy-18-methyl-19-norprogesterone; 16-Methylene-17α-hydroxy-18-methyl-19-norpregn-4-ene-3,20-dione acetate |
| Drug class | Progestin; Progestogen; Progestogen ester |
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| Chemical and physical data | |
| Formula | C24H32O4 |
| Molar mass | 384.516 g·mol−1 |
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18-Methylsegesterone acetate (18-methyl-SGA; also known as 18-methylnestorone) is a progestin medication of the 19-norprogesterone group which was never marketed.[1][2][3] It was first described in a patent in 1997 and then in a literature paper in 2003.[4][1] 18-Methyl-SGA is the C18 methyl or C13β ethyl derivative of segesterone acetate (SGA; 16-methylene-17α-acetoxy-19-norprogesterone), and shows 3 to 10 times the progestogenic potency of SGA in bioassays.[1] This is analogous to the case of the 19-nortestosterone progestin norethisterone and its 18-methyl derivative levonorgestrel, the latter showing substantially increased potency relative to the former similarly.[1] As SGA is already one of the most potent progestins to have been developed, with 100-fold the potency of progesterone and 10-fold the potency of levonorgestrel in bioassays, 18-methyl-SGA is an extremely potent progestogen, among if not the most potent known.[2][5][1]
SGA is a highly selective progestogen.[1][5] Like SGA, 18-methyl-SGA shows negligible affinity for the androgen receptor.[1][3] While 18-methyl-SGA has not been assessed at the other steroid hormone receptors, it is expected to be highly selective for the progesterone receptor similarly to SGA.[1] 18-Methyl-SGA shows over 16 times the affinity of progesterone for the progesterone receptor expressed in rat uterus.[1] In terms of oral bioavailability, it is known that SGA is not active orally, while the oral activity of 18-methyl-SGA is unknown.[1] The addition of an 18-methyl group to SGA is unlikely to affect its rate of delivery from sustained release systems.[1] As such, 18-methyl-SGA should be ideally suited for use via routes of administration like subcutaneous implants and transdermal patches.[1]
| Progestogen | PR RBA (rat uterus) |
Clauberg assaya |
Pregnancy maintenance |
|---|---|---|---|
| 18-Methyl-SGA | 355% | 0.3 μg | 0.03 mg |
| Segesterone acetate | 107% | 1 μg | 0.3 mg |
| Levonorgestrel | 100% | 3 μg | 0.3 mg |
| Progesterone | 22% | 100 μg | 1.0 mg |
| Footnotes: a = Minimum effective dose. Sources: [1] | |||
See also
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 "Synthesis and biological activity of a new progestogen, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3, 20-dione acetate". Steroids 65 (5): 266–74. May 2000. doi:10.1016/S0039-128X(99)00109-9. PMID 10751638.
- ↑ 2.0 2.1 "Nestorone: clinical applications for contraception and HRT". Steroids 68 (10–13): 907–13. November 2003. doi:10.1016/S0039-128X(03)00140-5. PMID 14667982.
- ↑ 3.0 3.1 "Nestorone as a Novel Progestin for Nonoral Contraception: Structure-Activity Relationships and Brain Metabolism Studies". Endocrinology 158 (1): 170–182. January 2017. doi:10.1210/en.2016-1426. PMID 27824503.
- ↑ 18-methyl 16-methylene 19-nor pregnane derivatives as progestins, pharmaceutical compositions containing them and process for the preparation thereof. https://patents.google.com/patent/WO1997023498A1/en
- ↑ 5.0 5.1 "Nestorone: a progestin with a unique pharmacological profile". Steroids 65 (10–11): 629–36. 2000. doi:10.1016/S0039-128X(00)00119-7. PMID 11108869.
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