## 1 Introduction  
In recent years, there has been a firm ambition to establish a worldwide system for global identification of medicinal products (IDMP). Each nationally authorized medicinal product anywhere in the world would receive a global identification number, so that the active substance, the dose form and the strength of the medicinal product can be recognised by health care workers and patients, anywhere in the world. This will allow the flow of prescriptions across borders, but also the flow of information about medicinal products, facilitating the development of decision support systems and patient-centred mobile applications. It started in 2012, with the publication of a series of ISO/CEN IDMP standards, addressing the crucial aspect of information on medicines in research and development, market authorisation, prescribing and dispensing, drug information, and pharmaco-epidemiology [1]. These standards provide guidance for the standardisation of substance representation,dose form terminology and expression of strength, the three basic elements for the identification of a Medicinal Product [2]. The ISO/CEN 13499:2012 standard and its technical specification focuses on dose forms [3]. This triggered, in 1995, a first reorganisation of the European Terminology for Dose forms in the European Pharmacopoeia, managed by the European Directorate for Quality in Medicines & Healthcare (EDQM) [4]. This Directorate is an administrative entity under the Council of Europe, grouping countries from Europe and beyond. The Food and Drug Administration (FDA) in the US expressed a clear intention to adopt IDMP and to welcome international collaboration [5]. The European Medicines Agency (EMA) developed a close cooperation with the FDA regarding the cleansing of pharmaceutical substance terminology [6; 7]. In 2019, the FDA and the World Health Collaborating Centre for Pharmacovigilance in Uppsala (WHO_UMC), and EMA developed a collaboration to test procedures to generate global identification numbers [8], now evolving to a global working group between these parties [9]. In 2020, EMA engaged in an ongoing process of writing an implementation guide for the implementation of IDMP within National Agencies [10]. Further, the pharmaceutical industry prepares for IDMP implementation in the submission of new applications for marketing authorisation. A number of consultancy companies has emerged, specializing in the issue. Next to substance identification, the identification and descriptive terminology for dose forms of medicinal products is crucial. The EDQM multilingual terminology on dose forms, revised in 2015 to adapt to the ISO/CEN standard, is used in the regulatory sphere in Europe, recommended by the International Council for Harmonisation, and used in many non-European countries [11]. In the US, the less granular RxNorm terminology of the National Library of Medicine is used [12]. In clinical care, the SNOMED-CT terminology has a separate chapter for dose forms, also inspired by the ISO/CEN standard [13]. All these pilot initiatives in the implementation of IDMP led to deeper insight in the theoretical aspects of the CEN/ISO standards. This experience is now fed into a revision cycle of these standards, currently ongoing [14]. This process runs synchronically with the UNICOM project, a large-scale Action Program of 4 years, launched at the end of 2019, to coordinate the efforts of 41 Partners (National Medicines Agencies and stakeholders), and to stimulate transatlantic cooperation [15]. It is clear that in the coming years, a decision will have to be taken on the choice for a global terminology for dose forms, as this is instrumental for creating global identification numbers for national medicinal products, ensuring semantic interoperability across information systems, languages and borders.