Epinephrine absorption from commercial gingival retraction cords in clinical patients.

Absorption of epinephrine from commercial gingival retraction cords was measured in vivo under clinical conditions. The amount of epinephrine absorbed was estimated by measurement with fluorospectrophotometry of the amount of dl-epinephrine remaining in the cords after they were removed and subtracting this value from the dl-epinephrine concentration in matching control cords. All cords lost substantial amounts of epinephrine while in the sulcus, with individual losses ranging from 64% to 94%. An average 71 micrograms of l-epinephrine was absorbed per inch of two-ply cord, and extreme variability in the dl-epinephrine concentration for individual segments of commercial cord was noted. In addition, the cords did not contain the concentration of epinephrine (500 micrograms/inch) listed on the package label but instead had a mean dl-epinephrine concentration of 225.5 micrograms/inch.