Lipid peroxide and hydrogen peroxide formation in parenteral nutrition solutions containing multivitamins

Background: Infusion of parenteral solutions containing peroxides may be de trimental to premature infants. Intralipid frequently contains lipid peroxi des and undergoes further peroxidation when exposed to light. Peroxidation is inhibited by ascorbate, and we have proposed that administration of pero xides could be minimized by mixing multivitamins with the Intralipid. In co ntrast, others have reported that multivitamins generate peroxides and have advised against mixing them with lipid. Our objective was to assess whethe r light-dependent reactions in parenteral solutions containing MVI Pediatri c (MVIP) generate hydrogen peroxide and establish whether addition of multi vitamins to Intralipid is beneficial or detrimental. Results: We were unabl e to make accurate peroxide measurements in MVIP using the ferrous oxidatio n of xylenol orange (FOX) assay, even though others have used it for this p urpose, because of interference by ascorbate. Therefore oxygen release on a dding catalase was measured to assay for hydrogen peroxide. Freshly reconst ituted solutions contained 250 to 500 mu mol/L hydrogen peroxide, and this increased dramatically in ambient light. This is presumably due to light-de pendent, riboflavin-catalyzed reduction of oxygen by ascorbic acid. The rat e of peroxide generation was less for MVIP diluted in Intralipid than in de xtrose solution. Conclusions: Taken together with our previous findings, we conclude that multivitamins protect Intralipid against lipid peroxidation, but light-dependent hydrogen peroxide production and ascorbate loss occur. These latter changes are less than for multivitamins in other total parent eral nutrition solutions, so there is an advantage in mixing multivitamins with Intralipid. However, prevention of ascorbate loss and hydrogen peroxid e formation in any multivitamin solution requires protection of the deliver y system from light.