7414-83-7

White Crystalline Solid

Etidronic acid is used as a calcium regulator. Etidronic acid is a bisphosphonate antiresorptive agent.

progestin

Used as a calcium regulator. A bisphosphonate bone resorptive inhibitor

ChEBI: An organic sodium salt resulting from the replacement of two protons from etidronic acid (one from from each of the phosphonic acid groups) by sodium ions.

Sequestering and chelating agent; scale and corrosion inhibitor.

Agents in the first generation (e.g., etidronate disodium and tiludronate) that were dosed continuously produced poorly mineralized bone, because there was no interval for appropriate bone mineralization to occur. Subsequent studies that used a cyclic dosing schedule (400 mg/day for 2 weeks, followed by 2.5 months of calcium supplementation only) showed improvement in bone mineralization. Etidronate has been approved for treatment of Paget's disease of the bone but not for treatment of osteoporosis. Tiludronate is approximately 10-fold more potent than etidronate and, when given orally for 6 months (200, 400, or 800 mg/day), increases BMD by 2%. No further bone loss was detected in patients 6 months after cessation of therapy.

Etidron,Gentili,Italy,1977

Phosphorous acid was premixed with acetic acid to form a 50 wt % solution of phosphorous acid dissolved in acetic acid. The acids were mixed on a molar basis of 1.36:1, acetic acid to phosphorous acid, and this corresponded on a mol percentage basis to 57.6% acetic acid and 42.4% phosphorous acid. Acetic anhydride was continuously metered into a stream of the phosphorous acid-acetic acid mixture to form the reaction solution. The acetic anhydride was metered into the acid mixture at a mol ratio of 1.33 mols of acetic anhydride per mol of phosphorous acid. The metering rates were 18.5 lb/hr of the phosphorous acid/acetic acid premixed solution and 15.1 lb/hr acetic anhydride. The reaction solution was continuously passed through a heat exchanger where it was heated to 190°F then it was continuously fed into a two stage back-mix reaction zone where due to the heat of reaction the temperature rose to 275°F. The average residence in the reaction zone was 27 min. The reaction zone consisted of two back-mix reactors each having a capacity of 7.5 pounds of the reaction solution. A stream of reaction solution was continuously with drawn from the second reactor and continuously mixed with a stream of water which was being metered at a rate of 2 lb/hr. This amount of water corresponded to 18% excess over the theoretical amount necessary to hydrolyze all of the acetyl-containing compounds in the reaction solution to free acids. The hydrolyzed solution was continuously passed through a heat exchanger and cooled to room temperature after which the solution was continuously passed to a crystallizer where, with agitation, the ethane-1-hydroxy-1,1-diphosphonic acid crystallized. The slurry was then filtered and the crystals were recovered and dried. Analysis of the product showed a conversion rate of phosphorous acid to ethane-1-hydroxy-1,1- diphosphonic acid of 86%. Sodium hydroxide may be used to give the disodium salt.

Didronel (Millot Laboratories, France); Didronel (Procter & Gamble).

Bone calcium regulator

Etidronate helps to guard chronic ocular hypertension prompted retinal oxidative stress. It stimulates the development of retinal ganglion cells through insulin-like growth factor 1 (IGF-1) signaling pathway. It may possess neuroprotective effects in in vivo and in vitro rat model of glaucoma. Etidronate belongs to bisphosphonates.

Etidronate is a first generation bisphosphonate that may be useful for the treatment of severe hypercalcemia associated with neoplastic disease. Its use in human medicine has been largely replaced with newer, more potent bisphosphonates that can be dosed less often or have fewer adverse effects. Etidronate is also indicated in humans for the treatment of Paget’s disease and heterotopic ossification (e.g., after total hip replacement).

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