Lincomycin serum and saliva concentrations after intramuscular injection of high doses.

Serum and saliva levels of lincomycin were determined in 15 normal adult male volunteers after a single intramuscular injection of 600, 1000, or 1500 mg lincomycin in a three-way crossover study. The area under the serum concentration-time curve did not increase in proportion to the increase in dose. The increase in concentration of lincomycin in saliva was greater than expected for the increase in dose. There were not significant differences in elimination half-life between doses. These results suggest that the apparent clearance of lincomycin increases with increasing dose possibly because of a decrease in serum protein binding of lincomycin at high serum concentrations.

Comedonal levels of free clindamycin following topical treatment with a 1% solution of clindamycin phosphate.

Comedones were extracted from twenty subjects using topical 1% clindamycin phosphate and were assayed for free clindamycin. Positive specimens were obtained from sixteen subjects at 2 weeks and from eighteen at 4 weeks, with levels of 0.06 to 1.49 micrograms/mg. Mean content was 0.39 +/- 0.08 micrograms/mg and 0.6 +/- 0.11 micrograms/mg, respectively. These values closely match levels previously determined following treatment with clindamycin hydrochloride, which may explain how these two esters can be similarly effective therapeutically. Satisfactory cooperation by the participants was likely obtained because their clinical progress paralleled that reported in other studies. Comedonal material reported as negative could very well contain effective levels of clindamycin, since minimum inhibitory concentrations of that antibiotic for most strains of Propionibacterium acnes are far below those detectable by current bioassay methods.