AN OVERVIEW OF THE TOXICOLOGY OF HFA-134A (1,1,1,2-TETRAFLUOROETHANE)

1 This paper reviews the results of preclinical toxicology studies on HFA-134a carried out by Glare Research and Development Ltd. 2 A compre hensive range of studies was conducted in animal models suitable for t he type of investigation. 3 The inhalation route of administration was used in all in vivo studies (with the exception of local tolerance an d sensitisation studies) as patients will be exposed only to vapour du ring actuation of metered-dose inhalers. Cell cultures used for in vit ro studies were also exposed to the vapour. 4 There was no mortality o f rodents or dogs at extremely high vapour concentrations (81%v/v). 5 HFA-134a was considered not to be toxic or oncogenic and to provide a safe alternative to chlorofluorocarbons for use in pharmaceutical mete red-dose inhalers.