Jens Kvist Madsen1,2, Lise Giehm3, Daniel E Otzen4. 1. Interdisciplinary Nanoscience Centre (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK 8000, Aarhus C, Denmark. 2. Department of Pharmaceutical Development, Zealand Pharma A/S, Smedeland 36, DK-Glostrup, Denmark. 3. Department of Pharmaceutical Development, Zealand Pharma A/S, Smedeland 36, DK-Glostrup, Denmark. lgi@zealandpharma.com. 4. Interdisciplinary Nanoscience Centre (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK 8000, Aarhus C, Denmark. dao@inano.au.dk.
Abstract
PURPOSE: The peptide hormone glucagon, used to treat hypoglycaemic incidents, is prone to aggregation. Generating alternatives with better stability is of pharmaceutical interest in the treatment of diabetes. Here we investigate the impact of six different surfactants on the solubility and stability of ZP-GA-1, a stable version of glucagon. METHODS: We use chemical surfactants (sodium dodecyl sulphate, dodecyl maltoside and polysorbate 20) and the biosurfactants rhamnolipid, sophorolipid and surfactin. We investigate their interaction with ZP-GA-1 by pyrene fluorescence, circular dichroism and isothermal titration calorimetry. RESULTS: All six surfactants induce α-helical structure in ZP-GA-1, SDS having the biggest impact and polysorbate 20 the smallest. SDS keeps ZP-GA-1 solubilised over >48 days as opposed to 29 days in DDM, 3 days in polysorbate 20 and 0 days in buffer. Similarly, much less SDS than DDM, polysorbate 20 or biosurfactant is needed to redissolve aggregated ZP-GA-1. ITC confirms this trend, with SDS exhibiting very strong, and polysorbate 20 very weak interactions. CONCLUSION: Simple surfactant structures promote stronger peptide interactions. ITC shows promise as a general strategy to predict surfactants' solubilising powers. Stronger enthalpic interactions improved the absolute solubility of ZP-GA-1 and their strength correlated to the absolute solubility of the peptides though not to the kinetics of precipitation.
PURPOSE: The peptide hormone glucagon, used to treat hypoglycaemic incidents, is prone to aggregation. Generating alternatives with better stability is of pharmaceutical interest in the treatment of diabetes. Here we investigate the impact of six different surfactants on the solubility and stability of ZP-GA-1, a stable version of glucagon. METHODS: We use chemical surfactants (sodium dodecyl sulphate, dodecyl maltoside and polysorbate 20) and the biosurfactants rhamnolipid, sophorolipid and surfactin. We investigate their interaction with ZP-GA-1 by pyrene fluorescence, circular dichroism and isothermal titration calorimetry. RESULTS: All six surfactants induce α-helical structure in ZP-GA-1, SDS having the biggest impact and polysorbate 20 the smallest. SDS keeps ZP-GA-1 solubilised over >48 days as opposed to 29 days in DDM, 3 days in polysorbate 20 and 0 days in buffer. Similarly, much less SDS than DDM, polysorbate 20 or biosurfactant is needed to redissolve aggregated ZP-GA-1. ITC confirms this trend, with SDS exhibiting very strong, and polysorbate 20 very weak interactions. CONCLUSION: Simple surfactant structures promote stronger peptide interactions. ITC shows promise as a general strategy to predict surfactants' solubilising powers. Stronger enthalpic interactions improved the absolute solubility of ZP-GA-1 and their strength correlated to the absolute solubility of the peptides though not to the kinetics of precipitation.
Authors: Robert A Rifkin; Edward T Maggio; Sonny Dike; Douglas A Kerr; Michael Levy Journal: J Neuroimmune Pharmacol Date: 2010-06-08 Impact factor: 4.147
Authors: András Micsonai; Frank Wien; Linda Kernya; Young-Ho Lee; Yuji Goto; Matthieu Réfrégiers; József Kardos Journal: Proc Natl Acad Sci U S A Date: 2015-06-02 Impact factor: 11.205