title: Assessment of ascorbic acid stability in different multilayered parenteral nutrition bags: critical influence of the bag wall material.
abstract: BACKGROUND
  The recent development of multilayered bags has minimized ascorbic acid oxidation in parenteral nutrition (PN) admixtures. However, the gas-barrier property of multilayered bags depends on their plastic material. This study compared ascorbic acid stability in different multilayered bags under experimental conditions.
  
  
  METHODS
  Oxygen permeability of a newly developed 6-layered bag (6-L) was compared with a highly mechanical-resistant 3-layered bag (3-L(R)) and a highly flexible 3-layered bag (3-L(F)) using gas chromatography. Ascorbic acid stability was assessed by iodine titration in bags filled with 2.5 L H(2)O and 40 g carbohydrates after setting residual O(2) content at < or =1 or > or =5 ppm. The effect of storage at 4 degrees C, 21 degrees C, and 40 degrees C on ascorbic acid stability was assessed over 48 hours in a complete PN admixture (ie, 330 g carbohydrates, 100 g lipids, 96 g amino acids and trace elements) using high-pressure liquid chromatography.
  
  
  RESULTS
  Oxygen permeability was markedly reduced in 6-L bags (0.5 mL O(2) /m(2)/d) compared with 3-L(R) (150 mL O(2) /m(2)/d) and 3-L(R) (1500 mL O(2)/m(2)/d). Accordingly, ascorbic acid was more stable in 6-L bags (half-life [T(1/2)] = 16 days up to 40 degrees C) than in 3-L(R) (T(1/2) = 9 days at 4 degrees C, 47 hours at 21 degrees C and 29 hours at 40 degrees C) and 3-L(F) (T(1/2) = 15 hours at 4 degrees C, 10 hours at 21 degrees C, and 6 hours at 40 degrees C). During the first 6 hours after PN admixture compounding, an additive ascorbic acid loss of 4.6 +/- 0.5 mg/L/ppm O(2) occurred because of residual O(2) in the bag.
  
  
  CONCLUSIONS
  The new combination of plastic layers and careful O(2) monitoring during the filling process allowed near to complete prevention of ascorbic acid degradation in multilayered PN bags during 48 hours, regardless of the storage temperature.
authors.affiliation: Clinical Nutrition and Central Laboratory of Medical Chemistry, Geneva University Hospital, CH-1211 Geneva 14, Switzerland.
authors.forename: Yves M
authors.initials: YM
authors.lastname: Dupertuis
authors.forename: Sihan
authors.initials: S
authors.lastname: Ramseyer
authors.forename: Marc
authors.initials: M
authors.lastname: Fathi
authors.forename: Claude
authors.initials: C
authors.lastname: Pichard
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D004349:Drug Packaging; D004355:Drug Stability; D004356:Drug Storage; D005526:Food, Formulated / Q000032:analysis* / Q000592:standards*; D006801:Humans; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis / Q000737:chemistry*; D010288:Parenteral Nutrition / Q000295:instrumentation* / Q000379:methods; D013696:Temperature; D013997:Time Factors
chemical_list: D001205:Ascorbic Acid; D010100:Oxygen