抄録
Recently, most total parenteral nutrition (TPN) fluids are now prepared in a clean room, and then are stocked in a pharmacy until use. After preparation, a time lag usually occurs before the onset of infusing TPN to patients. There are some unstable vitamins in such TPN fluid mixtures. Although a sufficient amount of vitamins are initially added to the fluids, it is necessary to ascertain whether or not a sufficient amount of vitamins remain in the mixture at the actual time of infusion.
In the present study, based on information available in the literature on time-dependent vitamin stability of various TPN fluids, the estimates of the essential quantity of vitamins infused were carried out by a modified procedure of a computating area under a pharmacokinetic curve (AUC). The expression of the Integrated Dose in Period (IDP) was replaced for the AUC. Through the survey of 1, 850 prescriptions over a one-month period, the combinations of most frequently used TPN liquids and vitamin A (VA), vitamin B1 (VB1), vitamin B2 (VB2), and vitamin C (VC) were selected. The theoretical vitamin contents in the TPN mixtures were estimated either at room temperature or in a shielded condition. For each vitamin, the expected remainder from the time of preparation up to 24 hours was designated as IDP0-24, the one from 12 hours after the preparation to 36 hours as IDP12-36, and that from 24 hours after to 48 hours as IDP24-48. The IDP values thus obtained were compared with the recommended standard daily intake of vitamins.
The results indicated that the IDP values for VA, VB2, and VC tended to be smaller than the daily recommended amounts under light illumination, thus suggesting the mixture should be shielded to help allow it to maintain the necessary amounts. On the other hand, regardless of the influence of light or shielding, sufficient IDPs of VB1 were observed at all the examined times. These results showed that the storage of fluids after being mixed with vitamins should be always maintained in a shielded condition. The present study theoretically demonstrated that under dark conditions, the time lag after TPN-vitamin mixture preparation would not affect the supply of VA, VB1, VB2and VC and the computation of IDP based on the stability data obtained from the literature was found to provide a good conventional measure for care-providers to ensure sufficient vitamin supplementation without performing time-consuming and laborious laboratory experiments.
