Meperidine binding to isolated alpha 1-acid glycoprotein and albumin.

Interpatient variability in response to a given dose of meperidine, a synthetic opiate analgesic, may be partially explained by variability in plasma protein binding. Alpha 1-acid glycoprotein (AAG), a plasma protein that primarily binds basic drugs, has been shown to increase in patients during stress such as trauma or surgery. The objective of this study was to determine the extent of meperidine binding to AAG and albumin as a function of both protein and meperidine concentrations. We performed a simple extraction procedure and a highly sensitive gas chromatograph analytical procedure. The results indicated that meperidine binding did not vary significantly with meperidine concentration at a given AAG concentration. However, meperidine binding increased significantly (p less than 0.01) as AAG concentration increased. Conversely, meperidine binding to albumin appeared to be independent of concentration of either meperidine or albumin. In conclusion, alpha 1-acid glycoprotein is a major plasma protein which binds meperidine in patients during stress. Further studies are suggested to elucidate the role of AAG on the pharmacologic effects of meperidine.