Addition of Amino Acids to Further Stabilize Lyophilized Sucrose-Based Protein Formulations: I. Screening of 15 Amino Acids in Two Model Proteins

Abstract

In small amounts, the low molecular weight excipients-sorbitol and glycerol-have been shown to stabilize lyophilized sucrose-based protein formulations. The purpose of this study was to explore the use of amino acids as low molecular weight excipients to similarly enhance stability. Model proteins, recombinant human serum albumin and α-chymotrypsin, were formulated with sucrose in combination with one of 15 amino acid additives. Each formulation was lyophilized at 1:1:0.3 (w/w) protein-sucrose-amino acid. Percent total soluble aggregate was measured by size-exclusion chromatography before and after storage at 50 °C for 2 months. Classical thought might suggest that the addition of the amino acids to the sucrose-protein formulations would be destabilizing because of a decrease in the system's glass transition temperature. However, significant improvement in storage stability was observed for almost all formulations at the ratio of amino acid used. Weak correlations were found between the extent of stabilization and both amino acid molar volume and side-chain charge. The addition of amino acids at a modest level generally improves storage stability, often by more than a 50% increase, for lyophilized sucrose-based protein formulations.

Investigating Structure and Dynamics of Proteins in Amorphous Phases Using Neutron Scattering

“…Although sugars and polyols, such as sorbitol and glycerol, have shown to improve the storage stability of lyophilized powders, amino acids can also exert a positive effect on the stability of lyophilized powders [127]. Neutron scattering can provide insights on the stabilization mechanism of these excipients at the molecular level, not only by measuring their effect on glass dynamics, but also by evaluating their influence on structural arrangements of proteins.…”

A Fluorescence‐based Method for Estimation of Oxygen Barrier Properties of Microspheres

“…We selected MD, as they provide varying levels of oxidative stability corresponding to a difference in their molecular weight (MW) (Anandaraman & Reineccius, 1986;Kilburn, Claude, Schweizer, Alam, & Ubbink, 2005;Townrow, Kilburn, Alam, & Ubbink, 2007). We evaluated the effects of introducing carbohydrates into Hi-cap100 formulations to determine the sensitivity of the methodology when lower MW carbohydrates are added to the higher MW Hi-cap100 (Forney-Stevens, Bogner, & Pikal, 2016). We also performed a sensitivity analysis to evaluate the sensitivity of effective oxygen diffusion coefficient (D eff ) estimation with varying particle radius.…”

Effects of lactic acid on the flexibility of the stratum corneum

“…One parameter related to physical adsorption of one material onto another is the dipole moment. The amino acids in NMF include glutamic acid, histidine, and arginine, which have dipole moments of 6.13, 4.04, and 5.78 D, respectively . The dipole moment of lactic acid is 1.14 D, and that of water, which is thought to directly interact with keratin, is 1.85 D .…”

“…The amino acids in NMF include glutamic acid, histidine, and arginine, [26][27][28] which have dipole moments of 6.13, 4.04, and 5.78 D, respectively. 29 The dipole moment of lactic acid is 1.14 D, 30 and that of water, which is thought to directly interact with keratin, is 1.85 D. 31 Thus, the dipole moment of lactic acid is similar to that of water and may be better for direct keratin protein binding than those of other NMFs. The interaction between lactic acid and keratin needs more detailed future study, including further examination of the possibility the effect of lactic acid on flexibility differs with age.…”