Non-reducing sugars as excipients in spray-dried powders for inhalation

In spray-dried formulations, various excipients or carriers are incorporated to improve the aerosolization behavior, stability and mechanical properties of active pharmaceutical ingredients (APIs) as well as to modify the pharmacokinetics and pharmacodynamics of APIs. Sugars are the most common excipients used as diluents and flow enhancers. In addition, sugars can provide hydrogen bonding and act as product stabilizers when water is removed.

Among the sugars, lactose is the most commonly used excipient in marketed dry powder inhaler products. However, due to its reducing nature (via the Maillard reaction), it is not suitable for stabilization of spray-dried powder formulations containing biological drugs with amines. Therefore, non-reducing sugars are recommended as stabilizers in spray-dried inhalation formulations. This article describes non-reducing sugars used as excipients in spray-dried powders for inhalation and their mechanism for stabilization and provides examples of spray-dried powder formulations composed of non-reducing sugars.