Rapid-Acting and Human Insulins: Hexamer Dissociation Kinetics upon Dilution of the Pharmaceutical Formulation

Abstract

PurposeComparison of the dissociation kinetics of rapid-acting insulins lispro, aspart, glulisine and human insulin under physiologically relevant conditions.MethodsDissociation kinetics after dilution were monitored directly in terms of the average molecular mass using combined static and dynamic light scattering. Changes in tertiary structure were detected by near-UV circular dichroism.ResultsGlulisine forms compact hexamers in formulation even in the absence of Zn2+. Upon severe dilution, these rapidly dissociate into monomers in less than 10 s. In contrast, in formulations of lispro and aspart, the presence of Zn2+ and phenolic compounds is essential for formation of compact R6 hexamers. These slowly dissociate in times ranging from seconds to one hour depending on the concentration of phenolic additives. The disadvantage of the long dissociation times of lispro and aspart can be diminished by a rapid depletion of the concentration of phenolic additives independent of the insulin dilution. This is especially important in conditions similar to those after subcutaneous injection, where only minor dilution of the insulins occurs.ConclusionKnowledge of the diverging dissociation mechanisms of lispro and aspart compared to glulisine will be helpful for optimizing formulation conditions of rapid-acting insulins.Electronic supplementary materialThe online version of this article (doi:10.1007/s11095-017-2233-0) contains supplementary material, which is available to authorized users.

Characterisation of insulin analogues therapeutically available to patients

“…The same phenomenon should have occurred for the native insulins if it were not for the fact that these fast acting analogues were designed to dissociate in this way, and is in agreement with the mode of action in vivo , where fast-acting analogues are injected subcutaneously and dissociate into the more effective monomer form faster than regular insulin. Similar conclusions were drawn by Gast et al, [ 40 ] who also studied the association/dissociation kinetics of these fast acting analogues.…”

A co-formulation of supramolecularly stabilized insulin and pramlintide enhances mealtime glucagon suppression in diabetic pigs

“…These insulin formulations contain a mixture of hexamers, dimers and monomers, which, upon subcutaneous injection, dissociate and are absorbed at different rates resulting in the delayed onset and long duration of action of these formulations ( Figure 1b ). [ 19 – 21 ] In contrast, the pramlintide monomer is absorbed rapidly from the subcutaneous space ( Figure 1b ). The lack of overlap between insulin and pramlintide pharmacokinetics in current treatment strategies hinders the synergistic effects of pramlintide and insulin action.…”

Profiling Insulin Oligomeric States by 1H NMR Spectroscopy for Formulation Development of Ultra-Rapid-Acting Insulin

“…Aspart with 80 mM nicotinamide shows a slight increase in dissociation rate, Figure 4a, and a corresponding decrease in R h and increase in polydispersity by DLS, Figure S7 (consistent with previous reports on the dissociation kinetics of rapid acting insulins on dilution). 13 With 130 mM nicotinamide, aspart has similar dissociation rate and R h , but the shift to 2 distinct diffusion behaviors with no change in MWeff or distribution, suggest that nicotinamide is shifting the population of the oligomeric species without affecting the hexamer dissociation rate. Likewise, the large change in dissociation rate observed at 260 mM nicotinamide coincides with a change in the distribution of both components of the diffusion profile.…”

“…Combined with insulin hexamer dissociation kinetic assays, dynamic light scattering (DLS), or other biophysical data, these simple NMR methods provide additional insight into formulated insulin behavior and further our understanding of the effects of excipients in fast-acting insulin formulation. 13…”