Pharmaceutical packaging wraps and protects drugs, and changes in packaging materials have a critical impact on product performance. Blisters, which consist of one type of primary packaging of polymer films, come into direct contact with the drug. The characterization of the primary packaging materials is an essential strategy for ensuring that they are suitable for the intended use. Recognizing this need, the new United States Pharmacopeia, which will come into effect in 2020, expands its considerations for characterization of packaging. However, the new document still contains limitations on the scope of the technical recommendations and does not consider multilayer films, which are widely used in industries. In the present work, five types of packaging films were characterized by Differential Scanning Calorimetry and Infrared Spectroscopy, both mentioned in the pharmacopeias; and also, to determine the thermal limits of the evaluated materials, by the Thermogravimetric Analysis. With the lack of references for multilayer films, the results were compared with divergent values published in the literature. It was identified, in the five materials analyzed, the existence of a plasticizer not identified by the manufacturers. This study confirms the importance of the characterization of the blisters, pointing to the need to not only expand the recommendations of the pharmacopeia, but also to include new materials and multilayer films, and the production of reference material for the polymers used in packages.