| Clinical data | |
|---|---|
| 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 |
| Routes of administration | Intramuscular injection |
| Drug class | Progestogen;Progestogen ester |
| ATC code |
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| Identifiers | |
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| CAS Number | |
| PubChemCID | |
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| CompTox Dashboard(EPA) | |
| ECHA InfoCard | 100.081.125 |
| Chemical and physical data | |
| Formula | C25H34O3 |
| Molar mass | 382.544 g·mol−1 |
| 3D model (JSmol) | |
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Levonorgestrel butanoate (LNG-B) (developmental code nameHRP-002),[1][2] orlevonorgestrel 17β-butanoate, is asteroidalprogestin of the19-nortestosterone group which was developed by theWorld Health Organization (WHO) in collaboration with the Contraceptive Development Branch (CDB) of theNational Institute of Child Health and Human Development as a long-actinginjectablecontraceptive.[3][4][5] It is the C17βbutanoateester oflevonorgestrel, and acts as aprodrug of levonorgestrel in the body.[4] The drug is at or beyond thephase III stage of clinical development, but has not been marketed at this time.[3] It was first described in the literature, by the WHO, in 1983, and has been under investigation for potential clinical use since then.[4][6]
LNG-B has been under investigation as a long-lasting injectable contraceptive for women.[7] A singleintramuscular injection of anaqueous suspension of 5 or 10 mg LNG-B has a duration of 3 months,[3][7] whereas an injection of 50 mg has a duration of 6 months.[1] The drug was also previously tested successfully as acombined injectable contraceptive withestradiol hexahydrobenzoate, but this formulation was never marketed.[7] LNG-B has been tested successfully in combination withtestosterone buciclate as a long-lasting injectablecontraceptive for men as well.[8][9]
LNG-B may have several advantages overdepot medroxyprogesterone acetate, including the use of much lower comparative dosages, reduced progestogenicside effects likehypogonadism andamenorrhea, and a more rapid return infertility following discontinuation.[7][10] The drug has a well-establishedsafety record owing to the use of levonorgestrel as anoral contraceptive since the 1960s.[7]
| Compound | Form | Dose for specific uses (mg)[c] | DOA[d] | |||
|---|---|---|---|---|---|---|
| TFD[e] | POICD[f] | CICD[g] | ||||
| Algestone acetophenide | Oil soln. | - | – | 75–150 | 14–32 d | |
| Gestonorone caproate | Oil soln. | 25–50 | – | – | 8–13 d | |
| Hydroxyprogest. acetate[h] | Aq. susp. | 350 | – | – | 9–16 d | |
| Hydroxyprogest. caproate | Oil soln. | 250–500[i] | – | 250–500 | 5–21 d | |
| Medroxyprog. acetate | Aq. susp. | 50–100 | 150 | 25 | 14–50+ d | |
| Megestrol acetate | Aq. susp. | - | – | 25 | >14 d | |
| Norethisterone enanthate | Oil soln. | 100–200 | 200 | 50 | 11–52 d | |
| Progesterone | Oil soln. | 200[i] | – | – | 2–6 d | |
| Aq. soln. | ? | – | – | 1–2 d | ||
| Aq. susp. | 50–200 | – | – | 7–14 d | ||
Notes and sources:
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17α-Hydroxyprogesterone caproate is a depot progestogen which is entirely free of side actions. The dose required to induce secretory changes in primed endometrium is about 250 mg. per menstrual cycle.
The results showed that after injection the concentration of plasma MA increased rapidly. The meantime of peak plasma MA level was 3rd day, there was a linear relationship between log of plasma MA concentration and time (day) after administration in all subjects, elimination phase half-life t1/2β = 14.35 ± 9.1 days.