Testolactone

Absorption

Testolactone is well absorbed from the gastrointestinal tract.

Toxicity

Oral LD50s in mouse and dog are 1630 mg/kg and 593-926 mg/kg, respectively.

Originator

Fludestrin,Heyden,W. Germany,1968

The Uses of Testolactone

Testolactone USP (Teslac) is used to treat Breast cancer.

The Uses of Testolactone

Antineoplastic; non-selective steroidal aromatase inhibitor that prevents the conversion from androgen to estrogen. Used in in the treatment of familial male precocious puberty. An effective anti-tumor agent.

Background

An antineoplastic agent that is a derivative of progesterone and used to treat advanced breast cancer.

Indications

For palliative treatment of advanced breast cancer in postmenopausal women.

Definition

ChEBI: Testolactone is a seco-androstane and a 3-oxo-Delta(1),Delta(4)-steroid.

Manufacturing Process

(a) Fermentation: A medium of the following composition is prepared: 3.0 grams cornsteep liquor solids; 3.0 grams NH4H2PO4; 2.5 grams CaCO3; 2.2 grams soybean oil; 0.5 gram progesterone and distilled water to make 1 liter. The medium is adjusted to pH 7.00.1. Then, 100 ml portions of the medium are distributed in 500 ml Erlenmeyer flasks and the flasks plugged with cotton and sterilized in the usual manner (i.e., by autoclaving for 30 minutes at 120°C). When cool, each of the flasks is inoculated with 5 to 10% of a vegetative inoculum of Cylindrocarpon radicola [the vegetative inoculum being grown from stock cultures (lyophilized vial or agar slant) for 48 to 72 hours in a medium of the following composition: 15 grams cornsteep liquor; 10 grams brown sugar; 6 grams NaNO3; 0.001 gram ZnSO4; 1.5 grams KH2PO4;0.5 gram MgSO47H2O; 5 grams CaCO3; 2 grams lard oil; and distilled water to make 1 liter].
The flasks are then placed on a reciprocating shaker (120 one and one-half inch cycles per minute) and mechanically shaken at 25°C for 3 days. The contents of the flasks are then pooled and, after the pH of the culture is adjusted to about 40.2 with sulfuric acid, filtered through Seitz filter pads to separate the mycelium from the fermented medium.
(b) Extraction: 40 liters of the culture filtrate obtained in (a) is extracted with 40 liters chloroform in an extractor (e.g., Podbelniak, US Patent 2,530,886, or improvements thereon) and the filtered chloroform extract is evaporated to dryness in vacuo. The residue (11.1 grams) is taken up in 200 ml of 80% aqueous methanol, and the resulting solution is extracted four times with 100 ml portions of hexane. The 80% aqueous methanol solution is then concentrated in vacuo until crystals appear; and, after cooling at 0°C for several (usually about 3 to 4) hours, the crystals formed are recovered by filtration. About 2.9 grams 1-dehydrotestololactone (MP 217° to 217.5°C) are thus obtained. Concentration of the mother liquors yields additionally about 6.0 grams of the lactone. Recrystallization from acetone yields a purified 1-dehydrotestololactone having a melting point of 218° to 219°C.

Therapeutic Function

Cancer chemotherapy

General Description

Testolactone, 13-hydroxy-3-oxo-13,17-secoandrosta-1,4-dien-17-oic acidΔ-lactone (Teslac),was originally synthesized as a possible anabolic steroid,considering its structural similarity to testosterone. The keystructural difference from anabolic steroids is the D-ring lactone instead of the typical cyclopentyl ring. Althoughconsidered in many texts an androgen or anabolic steroid (itis a Schedule III drug because of its classification as an anabolicsteroid), testolactone lacks androgenic effects in vivo.Its action is believed to be caused by irreversible inhibitionof aromatase. It is a relatively weak inhibitor of aromatase,but the irreversible nature of the inhibition can lead to prolongedeffects. Its relatively weak inhibition of aromataseand its undesirable dosage schedule (5×50-mg tabletsq.i.d.) give this older agent only limited use in breast cancertreatment because of better available options.

Pharmacokinetics

Testolactone is a synthetic anti-neoplastic agent that is structurally distinct from the androgen steroid nucleus in possessing a six-membered lactone ring in place of the usual five-membered carbocyclic D-ring. Despite some similarity to testosterone, testolactone has no in vivo androgenic effect. No other hormonal effects have been reported in clinical studies in patients receiving testolactone.

Metabolism

Hepatic. Metabolized to several derivatives in the liver, all of which preserve the lactone D-ring.