*5.3. Human Plasma*

Procedures using human blood in this study were approved by ethics committee of Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Brazil, and registered under CAAE 19892213.7.0000.5473. Human blood was collected from three volunteers who declared they had not used painkillers for at least 10 days. In order to obtain human plasma, blood was collected and anticoagulated with 0.1 vol. of 3.8% sodium citrate and centrifuged at 1000× *g* for 10 min at 4 ◦C. Whole plasma samples (n = 3) were designated as P(W).
