Sodium phosphates

Sodium phosphate is a generic term for the salts of sodium hydroxide and phosphoric acid. They are:

• sodium dihydrogen phosphate, commonly termed monosodium phosphate, (NaH₂PO₄), is also known as "sodium phosphate, monobasic".
• disodium hydrogen phosphate, commonly termed disodium phosphate, (Na₂HPO₄) is also known as "sodium phosphate, dibasic".
• Trisodium phosphate, commonly shortened to just sodium phosphate, (Na₃PO₄), is also known as "sodium phosphate, tribasic".
• sodium aluminium phosphate, (Na₈Al₂(OH)₂(PO₄)₄).^[1]

Sodium phosphates are often used as meat preservatives, as an alternative to sodium nitrite. This is common in canned meats.

Risk

Oral sodium phosphates for bowel preparation for colonoscopy may in some individuals carry a risk of kidney injury under the form of phosphate nephropathy. There are several oral phosphate formulations which are prepared extemporaneously. Oral phosphate prep drugs have been withdrawn in the United States, although evidence of causality is equivocal.^[2] Since safe and effective replacements for phosphate puratives are available, several authors have recommended general disuse of oral phosphates.^[3]

References

1. ^ Bell, Russel N (1973), "SODIUM ALUMINUM PHOSPHATE CHEESE EMULSIFYING AGENT", US Patent 3726960, April 
2. ^ Markowitz, GS; Perazella, MA (Aug 12), "Acute Phosphate Nephropathy", Kidney Int. 76 (10): 1027–34, doi:10.1038/ki.2009.308, PMID 19675530 
3. ^ Mackey, AC; Green, L; Amand, KS; Avigan, M (2009), "Sodium phosphate tablets and acute Phosphate Nephropathy", Am J Gastroenterol 104 (8): 1903–6, Aug, doi:10.1038/ajg.2009.342, PMID 19661931 

Lien, Nat Clin Pract Nephrol 2008, http://www.ncbi.nlm.nih.gov/pubmed/18797448, http://www.medscape.com/viewprogram/17294_pnt