The development of medicines for children. Part of a series on Pediatric Pharmacology, guest edited by Gianvincenzo Zuccotti, Emilio Clementi, and Massimo Molteni.

The lack of availability of appropriate medicines for children is an extensive and well known problem. As a consequence off label or unlicensed administration of medicinal products in every day paediatric practice is frequent. A variety of obstacles hinder the development of paediatric indications for drugs primarily intended for the adult market. The barriers to proper research on children's drug development include several complex factors, such as the limited commercial interest, lack of suitable infrastructure and competence for conducting paediatric clinical trials, difficulties in trial design, ethical worries and many others. Medicinal products used to treat children should be subjected to ethical research of high quality and be explicitly authorised for use in children as it happens in adults. Conducting adequate clinical trials in children is challenging and demanding. Identification of paediatric medical needs, extrapolation from adult data, modelling and simulation, specific clinical trial methodology are important features in the development of drugs intended for children. Market forces alone have proven insufficient to stimulate adequate research aimed at specific authorisation of medicinal products for the paediatric population, and for that reason, following the US experience, the European Paediatric Regulation has been amended in January 2007 by the European Commission. The objective of the Paediatric Regulation is to improve the development of high quality and ethically researched medicines for children aged 0 to 17 years, to facilitate the availability of information on the use of medicines for children, without subjecting children to unnecessary trials, or delaying the authorisation of medicines for use in adults. The impact of the Paediatric Regulation reflects in an increase in the number of paediatric studies to be performed, even if a significant number of these studies have not started yet. The objective of this review is to describe the main regulatory and scientific features which play a role in the complex issue of paediatric drug development. 2011 Elsevier Ltd. All rights reserved.