Investigation of drug product and container-closure interactions: A case study of diluent containing prefilled syringe.

Prefilled syringes (PFS) constitute a widely used medical device for drug delivery particularly for the drugs of biological origin. Interactions between the product contents and the components of the PFS play a critical role in determining the suitability of selected PFS. A diluent (with benzyl alcohol/BzOH as a preservative) containing PFS used for reconstitution of the lyophilized product revealed a systematic decrease in the BzOH content during accelerated and stress stability program. Investigation was carried out to understand and identify the underlying causes of this phenomenon. BzOH has a varying propensity to bind to the rubber components (stopper and tip-cap) of the PFS. Vapor permeation behavior across the tip-cap of the PFS was studied via headspace-gas chromatography-mass spectroscopy (HS-GC-MS) enabled analysis. Depending on the properties of the rubber components, BzOH can not only bind but also traverse across them, resulting in a systematic loss during the course of the stability. PFS can allow not only water vapor permeation across the tip-cap as shown in previous studies, but also molecules like benzyl alcohol. This phenomenon stresses the need for careful selection of the components of the primary packaging and also provides an opportunity to deploy novel tools like HS-GC-MS in the early selection of the optimal primary packaging configuration.