Predicting the Stability of Formulations Containing Lyophilized Human Serum Albumin and Sucrose/Trehalose Using...

Stabilization of proteins by disaccharides in lyophilized formulations depends on the interactions between the protein and the disaccharide (system homogeneity) and the sufficiently low mobility of the system. Human serum albumin (HSA) was lyophilized with disaccharides (sucrose and/or trehalose) in different relative concentrations. Solid-state nuclear magnetic resonance (ssNMR) spectroscopy ¹H T₁ and ¹H T_1ρ relaxation times were measured to determine the homogeneity of the lyophilized systems on 20-50 and 1-3 nm domains, respectively, with ¹H T₁ relaxation times also being used to determine the β-relaxation rate. HSA/sucrose systems had longer ¹H T₁ relaxation times and were slightly more stable than HSA/trehalose systems in almost all cases shown. HSA/sucrose/trehalose systems have ¹H T₁ relaxation times between the HSA/sucrose and HSA/trehalose systems and did not result in a more stable system compared with binary systems. Inhomogeneity was evident in a sample containing relative concentrations of 10% HSA and 90% trehalose, suggesting trehalose crystallization during lyophilization. Under these stability conditions and with these ssNMR acquisition parameters, a ¹H T₁ relaxation time below 1.5 s correlated with an unstable sample, regardless of the disaccharide(s) used.