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Chemical Stability of Selenious Acid in Total Parenteral Nutrition Solutions Containing Ascorbic Acid
Author(s) -
Ganther H.E.,
Kraus R.J.
Publication year - 1989
Publication title -
journal of parenteral and enteral nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.935
H-Index - 98
eISSN - 1941-2444
pISSN - 0148-6071
DOI - 10.1177/0148607189013002185
Subject(s) - ascorbic acid , parenteral nutrition , selenium , chemistry , enteral administration , chromatography , medicine , food science , organic chemistry
Reduction of selenious acid (H 2 SeO 3 ) to elemental Se by ascorbic acid was investigated in regard to the stability of selenite in total parenteral nutrition (TPN) solutions. [ 75 Se] H 2 SeO 3 (100 μg Se/liter) was incubated at 25°C with pure ascorbic acid (100 or 500 mg/liter) or added to complete TPN solutions containing similar levels of ascorbate. The mixtures were subjected to thin layer electrophoresis at pH 5.3 to separate HSeO 3 − from Se°. In complete TPN formulas, little or no reduction of HSeO 3 − to Se° occurred over a 24‐hr period, whereas complete reduction occurred with pure ascorbic acid. Further experiments showed that the amino acid component of the TPN formula was preventing the reduction of selenite, and that reduction of selenite by ascorbate did not occur in buffered solutions having a pH of 5 or greater. These results show that reduction of selenite is strongly influenced by pH. At the concentrations of H 2 SeO 3 and ascorbic acid commonly used, reduction to elemental Se is unlikely to be a practical problem in TPN solutions in the near‐neutral pH range. ( Journal of Parenteral and Enteral Nutrition 13 :185–188, 1989)