|Other names||LNG-B; HRP-002; Levonorgestrel 17β-butanoate; 17α-Ethynyl-18-methyl-19-nortestosterone 17β-butanoate; 17α-Ethynyl-18-methylestr-4-en-17β-ol-3-one 17β-butanoate|
|Drug class||Progestogen; Progestogen ester|
|Chemical and physical data|
|Molar mass||382.544 g/mol g·mol−1|
|3D model (JSmol)|
Levonorgestrel butanoate (LNG-B) (developmental code name HRP-002), or levonorgestrel 17β-butanoate, is a steroidal progestin of the 19-nortestosterone group which was developed by the World Health Organization (WHO) in collaboration with the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development as a long-acting injectable contraceptive. It is the C17β butanoate ester of levonorgestrel, and acts as a prodrug of levonorgestrel in the body. The drug is at or beyond the phase III stage of clinical development, but has not been marketed at this time. It was first described in the literature, by the WHO, in 1983, and has been under investigation for potential clinical use since then.
LNG-B has been under investigation as a long-lasting injectable contraceptive for women. A single intramuscular injection of an aqueous suspension of 5 or 10 mg LNG-B has a duration of 3 months, whereas an injection of 50 mg has a duration of 6 months. The drug was also previously tested successfully as a combined injectable contraceptive with estradiol hexahydrobenzoate, but this formulation was never marketed. LNG-B has been tested successfully in combination with testosterone buciclate as a long-lasting injectable contraceptive for men as well.
LNG-B may have several advantages over depot medroxyprogesterone acetate, including the use of much lower comparative dosages, reduced progestogenic side effects like hypogonadism and amenorrhea, and a more rapid return in fertility following discontinuation. The drug has a well-established safety record owing to the use of levonorgestrel as an oral contraceptive since the 1960s.
|Progestogen||Form||Major brand names||Class||TFD
|Algestone acetophenide||Oil solution||Perlutal, Topasel, Yectames||Pregnane||?||–||75–150 mg||100 mg ≈ 14–32 days|
|Cyproterone acetate||Oil solution||Androcur Depot||Pregnane||?||–||–||300 mg ≈ 20 days|
|Dydrogesteronea||Aqueous suspension||–||Retropregnane||?||–||–||100 mg ≈ 16–38 days|
|Gestonorone caproate||Oil solution||Depostat, Primostat||Norpregnane||50 mg||–||–||25–50 mg ≈ 8–13 days|
|Hydroxyprogesterone acetatea||Aqueous suspension||–||Pregnane||350 mg||–||–||150–350 mg ≈ 9–16 days|
|Hydroxyprogesterone caproate||Oil solution||Delalutin, Proluton, Makena||Pregnane||250–500 mgb||–||250–500 mg||65–500 mg ≈ 5–21 days|
|Levonorgestrel butanoatea||Aqueous suspension||–||Gonane||?||–||–||5–50 mg ≈ 3–6 months|
|Lynestrenol phenylpropionatea||Oil solution||–||Estrane||?||–||–||50–100 mg ≈ 14–30 days|
|Medroxyprogesterone acetate||Aqueous suspension||Depo-Provera||Pregnane||50–100 mg||150 mg||25 mg||50–150 mg ≈ 14–50+ days|
|Megestrol acetate||Aqueous suspension||Mego-E||Pregnane||?||–||25 mg||25 mg ≈ >14 daysc|
|Norethisterone enanthate||Oil solution||Noristerat, Mesigyna||Estrane||100–200 mg||200 mg||50 mg||50–200 mg ≈ 11–52 days|
|Oxogestone phenylpropionatea||Oil solution||–||Norpregnane||?||–||–||100 mg ≈ 19–20 days|
|Progesterone||Oil solution||Progestaject, Gestone, Strone||Pregnane||200 mgb||–||–||25–350 mg ≈ 2–6 days|
|Aqueous suspension||Agolutin Depot||Pregnane||50–200 mg||–||–||50–300 mg ≈ 7–14 days|
|Note: All by intramuscular or subcutaneous injection. All are synthetic except for P4, which is bioidentical. P4 production during the luteal phase is ~25 (15–50) mg/day. The OID of OHPC is 250 to 500 mg/month. Footnotes: a = Never marketed by this route. b = In divided doses (2 × 125 or 250 mg for OHPC, 10 × 20 mg for P4). c = Half-life is ~14 days. Sources: Main: See template.|