Background Excipients are used to facilitate the manufacturing of dosage forms and maintain the stability of medicines in the face of chemical and microbial challenges. The lack of neonatal safety information exposes these patients to the risk of specific adverse reactions unexpected from adult experience.

The European Study of Neonatal Excipient Exposure (ESNEE) consortium was created in order to improve experience on this topic. A systematic review of excipient safety and kinetics in humans and juvenile animals has been planned.

Purpose This study aimed to develop and validate a systematic and standardised search strategy for collecting relevant information about excipients.

Materials and methods 8 metadatabases were selected: PubMed, Scopus, Biosis, Inchem, AcTOR, Toxseek, International Pharmaceutical Abstract. Search focus was on the toxicity, safety and pharmacology of chemicals. An individual search strategy was developed for each resource.

Results Search strategy was developed using propylene glycol as a model. The systematic database review included 5 steps:

• ▶ definition of inclusion/exclusion criteria,

• ▶ source identification,

• ▶ adaptation of search strategies to each source,

• ▶ data assessment,

• ▶ database creation/use,

Inclusion and exclusion criteria were: English language, chemical product name (CPN) (not a derivative) mentioned in the abstract and its safety and/or toxicity on animal or human subjects evaluated; the CPN not cited as an example or used as a solvent in admixture, or for analytical matters. Boolean search strategy was not selective enough leading to too many irrelevant hits. Section Headings (SHs) search was more structured and narrowed the search without losing information. SHs had to be defined for each database. The relevance of abstracts was estimated independently by two pharmacists, using the inclusion/exclusion criteria. Articles identified will be assessed by experts in toxicology/pharmacokinetics before implementation into the ESNEE database.

Conclusions In future excipient monographs will summarise the data retrieved. They will provide the missing information needed to improve the safe use of drugs and drug formulations in neonates.