18-Methylsegesterone acetate

18-Methylsegesterone acetate (developmental code name NES-Ac), also known as 18-methyl-19-nor-17α-pregn-4-en-20-yn-17-ol acetate, is a progestin that was never marketed. It is a derivative of segesterone acetate (17α-acetoxy-16-methylene-19-norprogesterone) and is closely related to segesterone and dimethisterone. As a progestin, 18-methylsegesterone acetate is a synthetic hormone that mimics the action of progesterone, a natural hormone involved in the menstrual cycle and pregnancy.

Chemistry[edit | edit source]

18-Methylsegesterone acetate is a synthetic steroid and a derivative of progesterone, belonging to the group of 19-norprogesterones. It is specifically a 19-norsteroid, meaning it lacks the carbon atom at the 19th position, a characteristic feature of this class of compounds. The addition of a methyl group at the 18th position and an acetoxy group at the 17th position distinguishes it from its parent compound, segesterone acetate.

Pharmacology[edit | edit source]

Mechanism of Action[edit | edit source]

As a progestin, 18-methylsegesterone acetate works primarily by binding to and activating the progesterone receptor (PR), which regulates the expression of specific genes involved in the female reproductive system. By mimicking the action of natural progesterone, it can induce similar physiological effects, such as preparing the endometrium for pregnancy and maintaining pregnancy. Progestins are also involved in the suppression of gonadotropin secretion, which can inhibit ovulation and thus act as a method of contraception.

Pharmacokinetics[edit | edit source]

The pharmacokinetic profile of 18-methylsegesterone acetate, including its absorption, distribution, metabolism, and excretion, has not been extensively characterized due to its developmental status and lack of commercial availability.

Clinical Applications[edit | edit source]

18-Methylsegesterone acetate was investigated for potential use in hormonal contraception and other applications where progestin therapy is indicated. However, it has not been introduced to the market, and thus, its clinical efficacy and safety profile remain largely undefined.

Research[edit | edit source]

Research on 18-methylsegesterone acetate has been limited, and it has not progressed beyond the developmental stage. Its potential advantages over other progestins, such as improved safety profile or efficacy, have not been established.