Biochemical stabilization of glucagon at alkaline pH

Nicholas Caputo, Melanie A. Jackson, Jessica Castle, Joseph El Youssef, Parkash A. Bakhtiani, Colin P. Bergstrom, Julie M. Carroll, Matthew E. Breen, Gerald L. Leonard, Larry David, Charles Roberts, W. Kenneth Ward

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Background: For patients with type 1 diabetes mellitus, a bihormonal artificial endocrine pancreas system utilizing glucagon and insulin has been found to stabilize glycemic control. However, commercially available formulations of glucagon cannot currently be used in such systems because of physical instability characterized by aggregation and chemical degradation. Storing glucagon at pH 10 blocks protein aggregation but results in chemical degradation. Reductions in pH minimize chemical degradation, but even small reductions increase protein aggregation. We hypothesized that common pharmaceutical excipients accompanied by a new excipient would inhibit glucagon aggregation at an alkaline pH.

Methods and Results: As measured by tryptophan intrinsic fluorescence shift and optical density at 630nm, protein aggregation was indeed minimized when glucagon was formulated with curcumin and albumin. This formulation also reduced chemical degradation, measured by liquid chromatography with mass spectrometry. Biological activity was retained after aging for 7 days in an in vitro cell-based bioassay and also in Yorkshire swine.

Conclusions: Based on these findings, a formulation of glucagon stabilized with curcumin, polysorbate-80, l-methionine, and albumin at alkaline pH in glycine buffer may be suitable for extended use in a portable pump in the setting of a bihormonal artificial endocrine pancreas.

Original languageEnglish (US)
Pages (from-to)747-758
Number of pages12
JournalDiabetes Technology and Therapeutics
Volume16
Issue number11
DOIs
StatePublished - 2014

Fingerprint

Glucagon
Insulin Infusion Systems
Curcumin
Excipients
Albumins
Proteins
Endocrine System
Polysorbates
Type 1 Diabetes Mellitus
Tryptophan
Liquid Chromatography
Biological Assay
Methionine
Glycine
Mass Spectrometry
Buffers
Swine
Fluorescence
Insulin
Pharmaceutical Preparations

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Medical Laboratory Technology

Cite this

Caputo, N., Jackson, M. A., Castle, J., El Youssef, J., Bakhtiani, P. A., Bergstrom, C. P., ... Ward, W. K. (2014). Biochemical stabilization of glucagon at alkaline pH. Diabetes Technology and Therapeutics, 16(11), 747-758. https://doi.org/10.1089/dia.2014.0047

Biochemical stabilization of glucagon at alkaline pH. / Caputo, Nicholas; Jackson, Melanie A.; Castle, Jessica; El Youssef, Joseph; Bakhtiani, Parkash A.; Bergstrom, Colin P.; Carroll, Julie M.; Breen, Matthew E.; Leonard, Gerald L.; David, Larry; Roberts, Charles; Ward, W. Kenneth.

In: Diabetes Technology and Therapeutics, Vol. 16, No. 11, 2014, p. 747-758.

Research output: Contribution to journalArticle

Caputo, N, Jackson, MA, Castle, J, El Youssef, J, Bakhtiani, PA, Bergstrom, CP, Carroll, JM, Breen, ME, Leonard, GL, David, L, Roberts, C & Ward, WK 2014, 'Biochemical stabilization of glucagon at alkaline pH', Diabetes Technology and Therapeutics, vol. 16, no. 11, pp. 747-758. https://doi.org/10.1089/dia.2014.0047
Caputo, Nicholas ; Jackson, Melanie A. ; Castle, Jessica ; El Youssef, Joseph ; Bakhtiani, Parkash A. ; Bergstrom, Colin P. ; Carroll, Julie M. ; Breen, Matthew E. ; Leonard, Gerald L. ; David, Larry ; Roberts, Charles ; Ward, W. Kenneth. / Biochemical stabilization of glucagon at alkaline pH. In: Diabetes Technology and Therapeutics. 2014 ; Vol. 16, No. 11. pp. 747-758.
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