The distribution of sulfamerazin between plasma, cerebrospinal fluid, and bile in humans

The concentration-time curves of sulfamerazin were determined in plasma, cerebrospinal fluid (c.s.f.) and bile in two groups of patients (ventricle drainage and Kerr's T-tube drain). In plasma, a half-life of 13.6 hours as well as an invasion and evasion constant of 0.145 hours -1 and 0.051 hours -1, resepectively, were observed. The distribution of half-life times showed a bimodal behavior in these patients. The unbound part of sulfamerazin was 12% and the acetylated products 14%. Unlike plasma in c.s.f. and bile the influx is delayed up to steady state. The decreases of concentration in all three compartments are the same. The concentration ratio of sulfamerazin between C.S.F. and bile and plasma water amounted to 1 and 2.5, respectively. Of the given dose of sulfamerzin, 0.87% was eliminated by bile within 24 hours. The therapeutic conclusions are discussed with regard to the bimodal distribution of half-lives, the minimal inhibition concentrations and the unbound part in the plasma.