A technique for assessing the effects of pH and photodegradation on the stability of the iron chelate of ethyl N-methyl-4-hydroxy-5-oxo-3-pyrroline-3-carboxylate.
Ethyl N-methyl-4-hydroxy-5-oxo-3-pyrroline-3-carboxylate forms a deep red chelate with iron salts. The color intensity is directly related to the iron concentration. The photostability of the red color was determined at pH 1.2 and 5 by spectrophotometric assay at 484 nm at intervals during irradiation by tungsten light at 1020 microW/cm2. After 528 hr of continuous irradiation in deionized water, 90.9% of the iron chelate had decomposed. The reaction followed zero order kinetics. Maximal stability was observed at pH 5 at both 10(-1) and 10(-2) molar concentrations of the iron chelate; no detectable decomposition occurred after 192 hr of continuous irradiation. The iron chelate in biological tissues is stable for 18 months. The staining technique is superior to other histological methods for estimating low concentrations of iron in tissue.
Ball
M T
MT
Department of Pharmacy, School of Applied Sciences, De Montfort University, Leicester, United Kingdom.
Gupta
R
R
Sugden
J K
JK
D002712:Chlorides; D004355:Drug Stability; D005290:Ferric Compounds / Q000032:analysis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007502:Iron Chelating Agents / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D010777:Photochemistry; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D012996:Solutions; D013053:Spectrophotometry / Q000379:methods
D002712:Chlorides; D005290:Ferric Compounds; D007502:Iron Chelating Agents; D012996:Solutions; C091526:ethyl N-methyl-4-hydroxy-5-oxo-3-pyrroline-3-carboxylate iron chelate; D011761:Pyrrolidonecarboxylic Acid; C024555:ferric chloride