We investigated the stability of ascorbic acid (AA) and the sum of AA
plus dehydroascorbic acid (TAA) in a total parenteral nutrition (TPN)
mixture that contained 1000 ml Vamin 14, 1000 ml glucose 30%, 500 ml I
ntralipid 20%, potassium phosphate, a multivitamin preparation (Cernev
it) and trace elements. We used a spectrophotometer to measure AA and
TAA. AA decreased from 42.2 (+/-0.9) mu g/ml to 6.8 (+/-0.2) mu g/ml i
n 7 days. Over the same time the concentration of TAA decreased from 4
2.2 (+/-0.5) mu g/ml to 35.9 (+/-0.6) mu g/ml, i.e. 63.3 (+/-1.2)% of
the original concentration. When the solution was stored in glass bott
les and saturated with nitrogen or when trace elements were omitted, t
he concentration decreased by only 25.2 (+/-0.2)% and 23.8 (+/-1.6)% r
espectively over 7 days. The influence of oxygen, lipids, trace elemen
ts and underfilling the bag was also investigated. We,conclude that it
is acceptable to prepare these bags in advance and to store them for
7 days at 2-4 degrees C.