Abstract
Microbiological assay methods were investigated for quantitative determination of S-1108 in body fluids.
S-1108 concentration in body fluids was determined as the concentration of S-1006, the bioactive form of S-1108. The concentrations of S-1006 were assayed by the band-culture, cylinder-plate, agar-well and disc-plate methods using E. coli 7437 as the assay organism and trypto-soy agar (Eiken) as the assay medium. The minimal detectable concentrations for these bioassay methods were 0.01, 0.08, 0.16 and 0.16μg/ml, respectively.
To determine S-1006 levels in human plasma, consera were employed as diluents of the standard solutions instead of pooled human serum. When the urine specimens were diluted more than 10-fold, the standard solution was prepared with 0.1 M phosphate buffer (pH 7.0).
The concentrations of S-1006 in human plasma and urine obtained by the band-culture assay method were in good agreement with those obtained by HPLC analysis.
S-1006 in body fluids was stable at -20°C for at least 28 days.
