Protein Binding and Pharmacokinetics of Lincomycin Following Intravenous Administration of High Doses

High-dose infusions of lincomycin 600, 1,200, and 2,400 mg were administered to 14 healthy, adult men. Using model-independent pharmacokinetics, it was found that the half-life, mean residence time, and steady-state volume of distribution of total drug increased with dose, whereas the same parameters remained unchanged for the unbound lincomycin. Although the mean clearance value for total drug increased, this change fell short of being significant at the 5% level and was associated with a decrease in unbound clearance following administration of the 2,400 mg dose. Protein binding studies using ultrafiltration gave direct evidence of saturable serum protein binding and indicated that binding involved at least two distinct classes of binding sites.