Stability of hydrophilic vitamins mixtures in the presence of electrolytes and trace elements for parenteral nutrition: A nuclear magnetic resonance spectroscopy investigation

In total parenteral nutrition (TPN)​, esp. in the case of preterm infants, simultaneous administration of vitamins and trace elements is still a problematic issue: guidelines put in evidence the lack of specific documentation. In this work NMR spectroscopy was applied to the study of vitamins (pyridoxine hydrochloride, thiamine nitrate, riboflavin-​5'-​phosphate and nicotinamide) stability in presence of salts and trace elements. Vitamins in D2O were first analyzed by 1H NMR spectroscopy in absence of salts and trace elements; changes in chem. shifts or in diffusion coeffs., measured by NMR DOSY technique, were analyzed. The effects of salts and trace elements on single vitamins and on their admixts. were then investigated by performing quant. analyses during 48 h. Selected vitamins are subject to intermol. interactions. No degradative effects were obsd. in presence of salts and trace elements. Only riboflavin-​5'-​phosphate is subject to pptn. in presence of divalent cations; however, at low concn. and in presence of other vitamins this effect was not obsd. Solns. analyzed, in the condition of this study, are stable for at least 48 h and vitamins and trace elements can be administered together in TPN.