Compatibility of intravenous metronidazole with some all-in-one parenteral nutrition regimens

Supplementation of parenteral nutrition (PN) admixtures with other parenteral drugs may be desired especially in the case of polypharmacy and limited vascular access. Metronidazole (MTZ) is administered in surgical and critically ill patients often requiring concomitant nutritional therapy in the form of parenteral nutrition. The aim of the study was to evaluate the possibility of the concomitant administration of MTZ with PN admixtures from one container.

MTZ (1500 mg) was combined with six different PN admixtures and stored for 7 days before the simulation of administration. The mean droplet size (MDS) of the lipid emulsion, zeta potential, color, and pH of the tested samples were determined every 24 h. The content of MTZ was determined by the high-performance liquid chromatography method within the same time frames.

PN admixtures supplemented with MTZ were characterized by a pH range from 6.19 to 6.38 and zeta potential range from -21.6 mV to -8.8 mV. For all samples the pharmacopeial criteria for intravenously administered emulsions were met: The visual inspection showed no sign of emulsion destabilization or precipitation, and the MDS was <500 nm. The MTZ content remained >90% of the initial value throughout the whole study period.

Results showed the physicochemical compatibility and stability of PN admixtures supplemented with MTZ at the dose of 1500 mg. Such formulations can be stored at a temperature of 5°C for up to 7 d before administration to the patient.