Extraction/Leaching of Metal-Containing Additives from Polyvinyl Chloride, Ethyl Vinyl Acetate, and Polypropylene Bags and Infusion Sets into Infusion Solutions

Abstract

Flexible medical devices are primarily made of plasticized polyvinyl chloride (PVC). In recent times, to avoid undesired migration of the PVC plasticizers, ethyl vinyl acetate (EVA) and polypropylene (PP) has replaced PVC. Nevertheless, other additives are necessary to generate useful polymeric materials. Metallic species present in such additives can also leach out into the infusion solutions. The migration of barium (Ba), cadmium (Cd), lead (Pb), tin (Sn), and zinc (Zn) from devices made from PVC, EVA, and PP was evaluated. Bags and infusion sets were decomposed and their metallic contents analyzed. Glucose, NaCl, and Tween 80 were assessed as extraction media. These solutions were stored in PVC, EVA, and PP bags, heat-sterilized, and stored for 8 months at room temperature. Aliquots were taken before and after sterilization and then once per month to determine the contents of the metals. Commercial glucose and NaCl infusions were analyzed by taking aliquots of the solutions from the bags and from the administration set after their administration to patients. The three polymers contained the five metals. Ba was found in the highest concentration in all samples, with a mean of 8.0 mg/kg in PVC, 4.2 mg/kg in EVA, and 4.7 mg/kg in PP samples. Despite this, the only element that migrated into the glucose, NaCl, and Tween 80 solutions was Zn. The same result was found for the commercial glucose and NaCl infusions. Moreover, the Zn concentration in the administration sets was on average 52% higher than that found in the bags.LAY ABSTRACT: Flexible medical devices for infusions and artificial nutrition are made of plastics, such as polyvinyl chloride (PVC), ethyl vinyl acetate (EVA), and polypropylene (PP). These polymers contain additives necessary to generate useful materials. Metallic species present in these additives can leach out into the infusion solutions and come into contact with patients. To assess the risk of patient exposure to these metals, we evaluated the migration behavior of barium (Ba), cadmium (Cd), lead (Pb), tin (Sn), and zinc (Zn) from devices made from PVC, EVA, and PP. Bags and infusion sets were analyzed. Glucose, NaCl, and Tween 80 were investigated as extraction media. The three polymers contained the five metals. Ba was found in the highest concentration in all samples. Despite this, the only element that migrated into the glucose, NaCl, and Tween 80 solutions was Zn.

Keywords: Ethyl vinyl acetate; Medical devices; Metals; Migration; Polypropylene; Polyvinyl chloride.