Validation of the simplified UVB model to assess the pharmacodynamics of analgesics in healthy human volunteers

Authors
KI Lorenzini,ÊM Besson,ÊY Daali et al

Lab
Division of clinical pharmacology and toxicology University Hospitals of Geneva, Geneva, Switzerland

Journal
International Journal for Chemistry

Abstract
A pharmacokinetic/pharmacodynamic, randomized, crossover, placebo-controlled study was conducted in healthy human volunteers with the primary objective of exploring the existence of a positive interaction between paracetamol 1 g and ketorolac 20 mg intravenously on experimental pain models. Further, the simplified UVB model was validated as a screening tool for analgesics or a combination of analgesics in clinical drug development. It was observed that the UVB irradiation induced primary hyperalgesia, evidenced by significant decreases of the heat pain threshold from (mean ± SD) 46.9 ± 1.1 ¡C to 40.1 ± 1.7 ¡C (p <0.001) and of the mechanical pain threshold (62% decrease). A small intra- and inter-individual variability was observed as well as consistent intra-day stability for the heat pain threshold. The UVB irradiation also resulted in the development of an area of secondary hyperalgesia of 21.3 ± 11.3 cm(2). The mechanical pain threshold and area of secondary hyperalgesia showed small intra-individual variability and consistent intra-day stability. However, a greater variability was observed between subjects, which suggests that a crossover design would allow limiting the number of subjects.

BIOSEB Instruments Used:
Electronic Von Frey 4 (BIO-EVF4),Electronic Von Frey 5 with embedded camera (BIO-EVF5)