Stability and interaction studies, recent trends and future prospects: Container-content interactions
The primary packaging article is a fundamental part of a preparation, as it guarantees the integrity and safety of the drug in direct contact with it. It should therefore be chosen so as to generate as little interactions as possible with the pharmaceutical product it contains. However, the evaluation of content-container interactions is still insufficiently carried out in hospital pharmaceutical technology units, particularly the analysis of extractibles and leachables.
Content-container interactions are based on exchange phenomena between the packaging material(s) and the content (active ingredients, excipients) in contact. Theses interactions are linked to the nature of the materials, active ingredients and excipients but also to the conditions of preparation, sterilization or storage. Interactions may be ad(ab)sorption of the active ingredient on (into) the material, or migration of compounds from the container to the content. The consequences may be the following: a loss of activity of the active ingredient, toxicity of the leachables, degradation of the active substance by a released compound, a change in the pH of the preparation, a change in appearance of the container and possibly even the loss of its integrity…
All pharmaceutical preparations can be subject to container-content interactions but with a different criticity level, depending on the form and the route of administration. Particular attention should be paid to ophthalmic and injectable preparations.
The pharmacist must be vigilant with regards to the risk of interaction during the feasibility evaluation of hospital preparations. What information is required to make the correct choice of packaging according to the preparation? How can the quality of the container / content pair be checked?