Stability of milrinone lactate in the presence of 29 critical care drugs and 4 i.v. solutions

The stability of milrinone lactate in the presence of 29 critical care drugs during simulated Y-site injection and in 4 i.v. solutions was studied. Ten milliliters of milrinone 400 mu g/mL (as the lactate salt) was combined with 10 mt of each of 29 commonly used critical care drugs in 5% dextrose injection. Also, mixtures containing milrinone 400 mu g/mt in lactated Ringer's injection, 5% dextrose injection, 0.45% sodium chloride injection, and 0.9% sodium chloride injection were prepared. All mixtures were prepared in triplicate and stored at 22-23 degrees C in glass containers or polyvinyl chloride bags under fluorescent light. Samples were withdrawn zero, one, two, and four hours after mixing for each milrinone-secondary drug mixture and at intervals up to seven days for each milrinone-i.v. diluent mixture. Samples were examined visually and analyzed by high-performance liquid chromatography, enzymatic assay, or fluorescence polarization immunoassay. No precipitation or substantial pH change was observed in any of the mixtures. In all the mixtures, milrinone retained more than 96% of its initial concentration, and the other drugs retained more than 97% of their initial concentrations. Milrinone 400 mu g/mL in 5% dextrose injection and 29 critical care drugs were stable for four hours at 22-23 degrees C during simulated Y-site administration. Milrinone 400 mu g/mL was stable in lactated Ringer's injection, 5% dextrose injection, 0.45% sodium chloride injection,and 0.9% sodium chloride injection for seven days at 22-23 degrees C.