HPR -CRO GmbH – a Contract Research Organization (CRO) – has built a successful name in human pharmacodynamic research starting in 1976. Since more than 40 years, HPR - Human Pharmacodynamic Research, founded by Dr. med. Klaus Schaffler, MD, has been specializing in the electrophysiology and pharmacology of the human central nervous system (CNS) – as well as in human experimental pain research. In this period over 175 presentations/publications more than 150 phase-I studies with quite different objectives have been conducted, outlining medication onset, pain relief and providing insights into adverse effects objectively and subjectively. HPR is focused on Phase-I clinical trials in human pharmacodynamics and in combined pd/pk approaches for national and international pharmaceutical companies. Hereby, HPR has elaborated – besides other CNS-research approaches in vigilance and psychomotorics – a special model, the “Laser-Pain-Algesimetry”, under consideration of different sensitized and non-sensitized states of the skin to examine and analyze the effect of analgesic and anti-inflammatory compounds in humans. This well-developed and validated method of pain measurement guarantees a highly objective and quantitative approach to investigate the efficacy of analgesics by examining brain responses to repetitive nociceptive stimuli via “Evoked Potentials” – recorded on-line in real-time from Vertex-EEG position. This strong, unique and systematic methodological feature, together with flexible and creative study designs, as well as quick statistical data analysis and reporting, enables us to provide customers with outstanding examination and analysis of medication effects on CNS and pain processing – also based on an existing large data base of prior investigated analgesics and topicals (>50 !) in different compound groups and also based on a large scale of experimental and practical trial experience and competence in this field.