Etidronate

Etidronic acid

Clinical data
AHFS/Drugs.com	International Drug Names
License data	US FDA: Etidronate+disodium
Pregnancy category	US: C (Risk not ruled out)
Routes of administration	Oral, intravenous
ATC code	M05BA01 (WHO) M05BB01 (WHO)
Legal status
Legal status	In general: ℞ (Prescription only)
Pharmacokinetic data
Bioavailability	3%
Metabolism	Nil
Biological half-life	1 to 6 hours
Excretion	Renal and fecal
Identifiers
IUPAC name (1-hydroxyethan-1,1-diyl)bis(phosphonic acid)
CAS Number	2809-21-4 Y
PubChem CID	3305
IUPHAR/BPS	7184
DrugBank	DB01077 Y
ChemSpider	3189 Y
UNII	M2F465ROXU
KEGG	D02373 Y
ChEBI	CHEBI:4907 Y
ChEMBL	CHEMBL871 Y
ECHA InfoCard	100.018.684
Chemical and physical data
Formula	C2H8O7P2
Molar mass	206.028 g/mol
3D model (Jmol)	Interactive image
SMILES O=P(O)(O)C(O)(C)P(=O)(O)O
InChI InChI=1S/C2H8O7P2/c1-2(3,10(4,5)6)11(7,8)9/h3H,1H3,(H2,4,5,6)(H2,7,8,9) Y Key:DBVJJBKOTRCVKF-UHFFFAOYSA-N Y

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, abbreviated M_nHEDP (M: is a cation, n: number of M maximum 4).

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 stabiliser 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.

Etidronic acid can be prepared by reaction of Phosphorus trichloride with acetic acid in a tertiary amine, or by reaction of an acetic acid/acetic anhydride mixture with phosphorous acid.