Gentisic Acid, Sodium Salt

Gentisic acid (2,5-Dihydroxybenzoic acid, 5-hydroxysalicylic acid) is chemically related to salicylate and aspirin (acetylsalicylate) and shares with the latter agent analgesic and anti-inflammatory properties. Gentisic acid is an aromatic carboxylic acid used as a sample matrix in Matrix-assisted laser desorption/ionization Mass spectrometry. As a hydroquinone, it is readily oxidized and is used as an antioxidant excipient in some pharmaceutical preparations. In vitro stabilization of low-tin bone-imaging agents has previously been achieved with ascorbic acid. Gentisic acid is shown to be an equally effective antioxidant for the (1-hydroxyethylidene) diphosphonate (HEDP) and hydroxymethylenediphosphonate (HMDP) skeletal agents. In vitro studies show less than 2% free sodium [99mTc] pertechnetate at 24 hr with the gentisic acid stabilizer. Studies in guinea pigs at 3 and 24 hr-whether with C-14- or H-3-labeled gentisic acid as stabilizer-show no alteration in the biodistribution of either skeletal imaging agent by the addition of the gentisic acid. , Gentisic acid is a safe and effective stabilizer, and clinical studies have shown bioequivalency with ascorbic acid. Gentisic acid has been shown to be one of the most commenly occurring aromatic acids of green plants. Synonyms: 2,5-Dihydroxybenzoic acid, Sodium Salt, 5-Hydroxysalicylate sodium, CAS Number: 4955-90-2, Molecular Formula: C7H5O4Na, Molecular Weight: 176.10, Appearance: Supplied as a white to tan crystalline powder. Purity: >99%, Solubility (50mg/ml, H2O): Amber, clear, complete, pH (1%): 6.0-8.0, Loss of Drying: <16%, Residue on Ignition: <0.2%, Chloride: <0.0005%, Related Substances: < 0.5%, Storage: RT