Lyophilisation Closures

LYOPHILISED PHARMACEUTICALS

During the design of modern day pharmaceuticals, researchers have to consider a wide range of variables. A simple variable that needs to be considered is the colour of products and their packaging components for identification and marketing. One of the more difficult variables is the type of closure system a product will be packaged in, and how it will be administered. However, most modern day protein/peptide-based pharmaceuticals have been mainly confined to lyophilisation packaging systems. This is due to protein’s inability to maintain a suitable shelf-life in other pharmaceutical packaging environments, such as aqueous mediums in prefilled syringes and vials. Furthermore, oral administration of protein-based pharmaceuticals is not accomplishable, due to the extremely high acidic environment of the stomach.

LYOPHILISATION CLOSURES

Historically, the function of rubber closures was limited to maintaining a seal in the vial or barrel opening, confining a pharmaceutical within a vial or prefilled syringe and permitting proper removal of the pharmaceutical via a hypodermic needle. More recently the rubber closure has become an intricate part of the pharmaceutical closure system, especially regarding lyophilisation stoppers. Modern day lyophilisation stoppers are required to have a low gas and vapour permeability, low affinity to hold moisture, stability in the halfway-down position and vents which are large enough to allow efficient mass transfer during the lyophilisation process.

Also of importance, the closure must be able to establish and maintain seal integrity before and after crimping the aluminum cap. Along with all of these characteristics, a lyophilisation stopper needs to be universally compatible with different lyophilisation machinery. This article discusses topics associated with lyophilisation closures – including compound properties, closure design and coatings.