Lyophilisation – the process in which a liquid drug formulation is frozen and placed under a vacuum such that the ice changes directly from solid to vapour without passing through a liquid phase – has many advantages for moisture-sensitive drug products. In addition to preserving the characteristics of a potentially unstable drug, the benefits of the lyophilisation process include enhanced product stability in a dry state, rapid and easy dissolution of a reconstituted product, and ease of processing.1
Lyophilisation is an ideal process for drug products that may have a limited shelf-life or sensitivities to external influences. Some drug formulations are unstable in aqueous solutions; the molecules can interact and degrade quickly in water, so moisture-sensitive drugs are often lyophilised not only to protect them from outside elements, but also to protect them from their own eventual decay.2
Maintaining the stability of the lyophilised drug product during its shelf-life can be difficult for moisture-sensitive drug products
However, maintaining the stability of the lyophilised drug product during its shelf-life can be difficult for moisture-sensitive drug products, particularly if the elastomeric component selected for the primary containment system allows moisture vapour to migrate into the drug. Proper selection of the lyophilisation component and the rubber formulation can help to prevent risks and costs associated with disintegration of the freeze-dried drug product, often described as ‘lyo cake’, resulting in loss of drug product and patient confidence.