Polyhydric alcohols, protein stability effect

One group of kosmotropic stabilizers of proteins are the osmolytes, organic osmoprotectant solutes, mostly polyhydric alcohols and amino acids or their derivatives. Osmolyte compatibility of organisms is thought to result from absence of osmolyte interactions with substrates and cofactors, and the non-perturbing or favorable effects on macromolecular-solvent interactions (Yancey, 1982). 

One of the critical factors in excipient selection and concentration is the effect on preferential hydration of the biopharmaceutical product [53, 54], Preferential hydration refers to the hydration layers on the outer surface of the protein and can be utilized to thermodynamically explain both stability enhancement and denatur-ation. Typical excipients used in protein formulations include albumin, amino acids, carbohydrates, chelating and reducing agents, cyclodextrins, polyhydric alcohols, polyethylene glycol, salts, and surfactants. Several of these excipients increase the preferential hydration of the protein and thus enhance its stability. Cosolvents need to be added in a concentration that will ensure their exclusion from the protein surface and enhance stability [54], A more comprehensive review of excipients utilized for biopharmaceutical drug products is available elsewhere [48],... 

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