Parenteral aluminum loading in critical care medicine. Part I: Aluminum content of infusion solutions and solutions for parenteral nutrition.

BACKGROUND

For patients with disturbed aluminum (Al) excretion, a high Al intake is not without risk. As main aluminum sources infusion solutions and solutions for parenteral nutrition have been identified. This study will give current survey of aluminum loading of the above-mentioned preparations.

MATERIAL AND METHODS

The aluminum loading of 139 different infusion solutions and solutions for parenteral nutrition was determined. The solutions were from the clinical pharmacy of the Klinikum Steglitz of the Free University Berlin or were bought in a public pharmacy. The aluminum content was determined by means of two different, independent analytical methods: a) graphite furnace atomic absorption spectroscopy (GFAAS) and b) inductively coupled plasma atomic emission spectroscopy (ICP-AES). The agreement of the measured values was good except for five samples, where different values were found. Mistakes due to contamination were excluded on the basis of the results of measuring standard reference materials.

RESULTS

Small-volume additives of TPN (total parenteral nutrition) formulations were highly contaminated with aluminum, e.g. Ca and phosphate solutions (29-12,000 micrograms/l), vitamin C solutions (700-1,200 micrograms/l) and trace element solutions (67-6,200 micrograms/l). Furthermore about 44% of the crystalline amino acid solutions and lipid emulsions had an aluminum content of 25 to 55 micrograms/l. Low aluminum levels were found in carbohydrate solutions, NaCl and KCl solutions and in distilled water (aqua ad injectabilia).

CONCLUSIONS

Many of the solutions for parenteral nutritional support have an aluminum content which exceeds, in part considerably, the suggested threshold concentration of 25 micrograms/l (0.93 mumol/l), recommended by the American Society for Clinical Nutrition (ASCN) and the American Society for Parenteral and Enteral Nutrition (ASPEN). The pharmaceutical industry should be required to check the manufacturing process for avoidable sources of contamination, and threshold values for aluminum loading by intravenously applied pharmaceuticals should be laid down in the German and European pharmacopoeia. In cases where contaminations cannot be eliminated during the manufacturing process after careful checking, the aluminum content of the infusion solution should be declared for the user.