Stability of filgrastim and epoetin alfa in a system designed for enteral administration in neonates

OBJECTIVE: To determine the stability of recombinant granulocyte colony-sti mulating factor (rG-CSF, filgrastim) and recombinant erythropoietin (rEpo, epoetin alfa) in a solution designed for enteral administration in the neon atal intensive care unit. DESIGN: Filgrastim and epoetin alfa were added to a solution with NaCl 0.9% , sodium acetate, potassium chloride, and human albumin in concentrations d esigned to mimic human amniotic fluid. Additionally, the solution was dripp ed through polyvinyl chloride feeding tubes to simulate feedings, and aliqu ots were collected before, during, and after priming of the tube. Other ali quots were either frozen immediately, stored at room temperature, or refrig erated for 0, 6, 12, 18, and 24 hours. MAIN OUTCOME MEASURES: Filgrastim and epoetin alfa concentrations in the va rious aliquots were compared with the concentrations in the original soluti on. RESULTS: Filgrastim and epoetin alfa concentrations were stable for at leas t 24 hours when refrigerated and for at least three weeks when frozen. At r oom temperature, filgrastim was stable for 18 hours and epoetin alfa for 24 hours. Filgrastim concentrations did not vary significantly before, during , or after priming of the feeding tube, whereas epoetin alfa concentrations decreased significantly unless the feeding tube was primed with 10 mL of s olution. CONCLUSIONS: Filgrastim and epoetin alfa were stable in our amniotic fluid- like solution. In this respect, our solution is suitable for enteral admini stration to patients in the neonatal intensive care unit.