Not water, but formalin, dissolves urate crystals in tophaceous tissue samples.
OBJECTIVE
To examine the relative solubility of urate crystals in water, formalin, and ethanol.


METHODS
Weighed aliquots of synthetic crystals were incubated in each solvent for 72 h at 4 degrees C and were then examined by polarized microscopy.


RESULTS
urate crystals were insoluble in alcohol, sparingly soluble in water, and markedly soluble in formalin.


CONCLUSIONS
The marked solubility of urate in formalin is consistent with formation of urate:formaldehyde addition products.
Simkin
P A
PA
Department of Medicine, University of Washington, Seattle 98195.
Bassett
J E
JE
Lee
Q P
QP
D003460:Crystallization; D000431:Ethanol / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry*; D006073:Gout / Q000473:pathology; D006801:Humans; D012995:Solubility; D014527:Uric Acid / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D014867:Water; D005557:Formaldehyde; D014527:Uric Acid; D000431:Ethanol