Development of Protein-Specific Analytical Methodologies to Evaluate Compatibility of Recombinant Human (rh)IGF-1/rhIGFBP-3 with Intravenous Medications Co-Administered to Neonates

J Pharm Sci. 2022 May;111(5):1486-1496. doi: 10.1016/j.xphs.2021.10.027. Epub 2021 Oct 28.


The protein complex of recombinant human insulin-like growth factor-1 and insulin‑like growth factor binding protein‑3 (rhIGF-1/rhIGFBP-3; mecasermin rinfabate), is an investigational product for the prevention of complications of prematurity. Delivery of rhIGF-1/rhIGFBP-3 is by continuous central line intravenous infusion in preterm infants until endogenous IGF-1 production begins. Protein-specific analytical methodologies were developed to evaluate the compatibility of rhIGF-1/rhIGFBP-3 at low protein concentrations (∼2.5-10 μg/mL) expected when co-administered with other required medications in the NICU. Highly sensitive detection of the biologic potential degradants (fragments) and/or molecular modifications (oxidized species, aggregates) required the use of reversed-phase high-performance liquid chromatography and size-exclusion ultra-performance liquid chromatography coupled with mass spectrometric detection. We report on the quantification of rhIGF-1/rhIGFBP-3, its components and degradants, to a limit of quantitation of 3.1 μg/mL upon mixing with 24 commonly administered neonatal medications. Methods developed for the rhIGF-1/rhIGFBP-3 admixtures, optimized in studies with furosemide, caffeine citrate and ampicillin, demonstrated good reproducibility, linearity, and limit of detection/quantitation. Using these methods, no increase in degradation of rhIGF-1/rhIGFBP-3 components and no increase in oxidation or aggregation level was observed with caffeine citrate, while admixtures of rhIGF-1/rhIGFBP-3 with ampicillin yielded lower mass recovery of rhIGF-1/rhIGFBP-3 components, which likely resulted from adduct formation. Furosemide was found to be physically incompatible with rhIGF-1/rhIGFBP-3. Our findings support the use of these methodologies for detection of protein modifications under various clinical administration conditions, and additionally supplement physical compatibility data studies of ultra-low concentrations of rhIGF-1/rhIGFBP-3 post co-administration to preterm infants with other medications (manuscript in-preparation).

Keywords: Biopharmaceutical characterization; Degradation product(s); HPLC (high-performance/pressure liquid chromatography); Liquid Chromatography-Mass spectrometry (LC-MS); Physical stability; Protein aggregation.

MeSH terms

  • Ampicillin
  • Furosemide*
  • Humans
  • Infant
  • Infant, Newborn
  • Infant, Premature
  • Insulin-Like Growth Factor I*
  • Recombinant Proteins
  • Reproducibility of Results


  • Recombinant Proteins
  • Insulin-Like Growth Factor I
  • Ampicillin
  • mecasermin
  • Furosemide