HUMAN VOLUNTEER STUDIES WITH NONPHARMACEUTICAL CHEMICALS - METABOLISMAND PHARMACOKINETIC STUDIES

1 Human volunteer studies are an essential part of drug development bu t their use in the area of non-pharmaceutical chemicals has so far bee n very limited. Such studies can have considerable value in the assess ment and improvement of the safe use of chemicals. 2 Once metabolic pa thways and target metabolites have been identified in volunteers this information can be used in studies in the workplace or in the general population. Studies should be performed selectively only if there is b oth a toxic hazard and a significant exposure potential. In addition, they should only be carried out if the required information cannot be obtained in any other way. 3 Volunteer studies with non-pharmaceutical s have become increasingly acceptable in the light of established inte rnational guidelines, no-fault compensation, improvements in study des ign and technical developments which allow the use of very low dose le vels. The final decision on whether to carry out a study must always r est with an independent ethical committee. 4 The practical aspects of the study should be specified in a detailed protocol conforming with t he principles of good clinical practice. The safety of volunteers must be of paramount concern throughout. Depending on the nature of the ch emical and the study, it may be advisable to carry out studies in a cl inical facility where equipment is available for the treatment of any emergencies that might occur. 5 Numerous investigators have now shown that human volunteer studies are ethically acceptable, practicable and yield important information. The risk to volunteers is minimal and th is approach can lead to an improved foundation for occupational hygien e standards, more accurate risk assessment and thus better protection of the workforce and the general population.