Etidronic acid

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Etidronic acid
Etidronic acid.svg
Systematic (IUPAC) name
(1-hydroxyethan-1,1-diyl)bis(phosphonic acid)
Clinical data
AHFS/Drugs.com International Drug Names
Licence data US FDA:link
Pregnancy cat. C (US)
Legal status Prescription only
Routes Oral, intravenous
Pharmacokinetic data
Bioavailability 3%
Metabolism Nil
Half-life 1 to 6 hours
Excretion Renal and fecal
Identifiers
CAS number 2809-21-4 YesY
ATC code M05BA01 M05BB01
PubChem CID 3305
DrugBank DB01077
ChemSpider 3189 YesY
UNII M2F465ROXU YesY
KEGG D02373 YesY
ChEBI CHEBI:4907 YesY
ChEMBL CHEMBL871 YesY
Chemical data
Formula C2H8O7P2 
Mol. mass 206.028 g/mol
 YesY (what is this?)  (verify)

Etidronic acid (INN) or 1-hydroxyethane 1,1-diphosphonic acid (HEDP) is a bisphosphonate used in detergents, water treatment, cosmetics and pharmaceutical treatment.

An etidronate is a salt of etidronic acid, abbeviated MnHEDP (M: is a cation, n: number of M maximum 4).

Chelating Agent and Anti-oxidant[edit]

Etidronic acid is a chelating agent and may be added to bind or, to some extent, counter the effects of substances, such as calcium, iron or other metal ions, which may be discharged as a component of grey wastewater and could conceivably contaminate groundwater supplies. As a phosphonate it has corrosion inhibiting properties on unnalloyed steel. Etidronic acid also acts to retard rancidification and oxidation of fatty acids.

HEDP and its salts are added to detergents and other cleaning agents to prevent the effects of hard water. It is also used in peroxide bleaching to prevent degradation of peroxides by transition metals.

Etidronic acid is listed as an ingredient of several cosmetic formulations where it is used for suppressing radical formation, emulsion stabilser and viscosity control. While etidronic acid has not been limited from inclusion in cosmetics and does have legitimate uses, it is recommended that, as with most cosmetic products (particularly soaps), the product should be thoroughly rinsed from the skin after use.

Etidronic acid is also included among swimming pool chemicals. It is used as a stain inhibitor to prevent metal ions coming out of solution and staining the sides of swimming pools.

Use[edit]

Pharmaceutical[edit]

Etidronic acid (trade name Didronel) is a bisphosphonate used to strengthen bone, treat osteoporosis, and treat Paget's disease of bone.

Bisphosphonates primarily reduce osteoclastic activity, which prevents bone resorption, and thus moves the bone resorption/formation equilibrium toward the formation side and hence makes bone stronger on the long run. Etidronate, unlike other bisphosphonates, also prevents bone calcification. For this reason, other bisphosphonates, like alendronate, are preferred when fighting osteoporosis. To prevent bone resorption without affecting too much bone calcification, etidronate must be administered only for a short time once in a while, for example for two weeks every 3 months. When given on a continuous basis, say every day, etidronate will altogether prevent bone calcification. This effect may be useful and etidronate is in fact used this way to fight heterotopic ossification. But in the long run, if used on a continuous basis, it will cause osteomalacia.

Chemical[edit]

Main article: Corrosion inhibitor

HEDP is used as scale and corrosion inhibition in circulating cool water system, oil field and low-pressure boilers in fields such as electric power, chemical industry, metallurgy, fertilizer, etc. In light woven industry, HEDP is used as detergent for metal and nonmetal. In dyeing industry, HEDP is used as peroxide stabilizer and dye-fixing agent; In non-cyanide electroplating, HEDP is used as chelating agent. The dosage of 1–10 mg/L is preferred as scale inhibitor, 10–50 mg/L as corrosion inhibitor, and 1000–2000 mg/L as detergent. Usually, HEDP is used together with polycarboxylic acid.