TY - JOUR
T1 - Adsorption of insulin with varying self-association profiles to a solid Teflon surface-Influence on protein structures, fibrillation tendency and thermal stability
AU - Jørgensen, Lene
AU - Bennedsen, Pernille
AU - Hoffmann, Søren Vrønning
AU - Pinholt, Charlotte
AU - Krogh, Rasmus Linnemann
AU - Jensen, Minna Grønning
AU - Hostrup, Susanne
AU - Burkinksky, Jens T.
PY - 2011/4/18
Y1 - 2011/4/18
N2 - Interfaces are present in the preparation of pharmaceutical products and are well known for having an influence on the physical stability of proteins. The aim of this study was to examine the conformation (i.e. secondary and tertiary structures) and fibrillation tendency, overall aggregation tendency and thermal stability of adsorbed human insulin at a solid particulate Teflon surface. The effects of changes in the association degree of insulin on the structure and stability have been determined. Using SEC-HPLC, association profiles were determined for insulin aspart, zinc-free human insulin and human insulin with two Zn2+ per hexamer in concentrations ranging from 0.1 mg/ml to 20 mg/ml. Insulin aspart was 100% monomeric, regardless of concentration. In contrast, human insulin went from 100% monomer to 80% hexamer, and 20% dimer/monomer and zinc-free human insulin from 100% monomer to 70% dimer and 30% monomer with increasing concentration. The secondary structure of the insulins changed upon adsorption, but only minor differences were observed among the insulins. Structural changes were observed when the insulin-surface ratio was varied, but at no point did the structure resemble that of fibrillated insulin in solution. The presence of particles resulted in increased fibrillation of human insulin. The lag-time of fibrillation decreased, when the amount of particles present was increased. In conclusion, the type and association degree of the three insulin variants has no major influence on the secondary structure observed after adsorption of insulin at the solid Teflon surface. However, the presence of particles increases the tendency of insulin to fibrillate.
AB - Interfaces are present in the preparation of pharmaceutical products and are well known for having an influence on the physical stability of proteins. The aim of this study was to examine the conformation (i.e. secondary and tertiary structures) and fibrillation tendency, overall aggregation tendency and thermal stability of adsorbed human insulin at a solid particulate Teflon surface. The effects of changes in the association degree of insulin on the structure and stability have been determined. Using SEC-HPLC, association profiles were determined for insulin aspart, zinc-free human insulin and human insulin with two Zn2+ per hexamer in concentrations ranging from 0.1 mg/ml to 20 mg/ml. Insulin aspart was 100% monomeric, regardless of concentration. In contrast, human insulin went from 100% monomer to 80% hexamer, and 20% dimer/monomer and zinc-free human insulin from 100% monomer to 70% dimer and 30% monomer with increasing concentration. The secondary structure of the insulins changed upon adsorption, but only minor differences were observed among the insulins. Structural changes were observed when the insulin-surface ratio was varied, but at no point did the structure resemble that of fibrillated insulin in solution. The presence of particles resulted in increased fibrillation of human insulin. The lag-time of fibrillation decreased, when the amount of particles present was increased. In conclusion, the type and association degree of the three insulin variants has no major influence on the secondary structure observed after adsorption of insulin at the solid Teflon surface. However, the presence of particles increases the tendency of insulin to fibrillate.
KW - Former Faculty of Pharmaceutical Sciences
U2 - 10.1016/j.ejps.2011.02.007
DO - 10.1016/j.ejps.2011.02.007
M3 - Journal article
C2 - 21352910
SN - 0928-0987
VL - 42
SP - 509
EP - 516
JO - Norvegica Pharmaceutica Acta
JF - Norvegica Pharmaceutica Acta
IS - 5
ER -