ABSTRACT
Stabilising excipients are essential in formulations of protein drug lyophilisates. Sugars such as sucrose and trehalose are classically used as amorphous matrix formers, embedding the protein molecules and forming hydrogen bonds. Some amino acids such as l-arginine or sugar polymers such as cyclodextrins provide alternatives for this function. Protein stabilisation is supported by buffers and some further additives such as serum albumin, antioxidant-specific, or protein-specific molecules. To gain a pharmaceutically elegant cake, mannitol or some amino acids are used as a bulking agent. Various sugars, polymers, amino acids, and buffers can be used to increase both Tg ′ and Tg to potentially enable faster drying, provide improved cake appearance, and improve long-term protein stability. Thereby, some excipients fulfil several functions at the same time. Although the quest for new excipients is ongoing, success is limited by roadblocks arising from regulatory concerns, toxicological testing requirements, and the existing wealth of experience with established excipients.
