Table 4

Correlation summary of radiometric HPLC and HPLC MS peaks characterized in human excreta

Metabolite or PeakName14C Retention TimeMH+MS Retention TimeLowest/Highest Individual % of Dose*No. patients   with 14C peak4-aMetabolite or Artifact
min min
M1SN-38N-oxide5.1–5.3409 with 393 fragment6.05N.D. /0.434 /8Radioimpurity or metabolite
M2Unknown6.0–6.5N.D. /0.124 /8Unknown
M3SN-38 glucuronide7.4–7.85698.112.54 /4.688 /8Major Metabolite
M4Unknown8.6N.D. /0.574 /8Unknown
M5CPT-11 hydroxy acid9.9–10.36059.120.13 /0.388 /8Parent-equilibrium artifact
M6Unknown10.9N.D. /0.021 /8Unknown
M7Unknown11.3–11.60.34 /2.08 /8Unknown
M8Hydroxy CPT-1111.9–12.960311.010.02 /0.538 /8Possible metabolite in bile
M9Primary amine (NPC)12.9–13.651911.240.22 /2.668 /8Metabolite
M10Hydroxy CPT-1113.6–14.260312.270.04 /0.978 /8Possible metabolite
M11APC14.3–15.161912.536.19 /14.018 /8Major Metabolite
M12Hydroxy CPT-11/Lokiec 74-b 16.660314.39N.D. /0.112 /8Impurity
PDP-14-c/Lokiec 656113.45N.D. /N.D.0 /8Impurity-MS only
M13Lokiec 154-b 17.1–17.449115.45N.D. /0.332 /8Degradation artifact of NPC or  metabolite of impurity M14
M14PDP-2/Lokiec 54-b 17.855916.38N.D. /0.374 /8Impurity/degradation artifact
CPT-1118.4–19.758717.1045.39 /63.068 /8Parent Drug
M15Unknown20.1–21.0N.D. /0.182 /8Unknown
M16Unknown21.0–22.0N.D. /0.141 /8Unknown
M17SN-3822.0–23.539321.416.19 /12.78 /8Active metabolite
M18Unknown24.9N.D. /0.121 /8Unknown
M19PDP-3, -4, -54-c 25.9–26.0559/529/54327.45N.D. /0.463 /8Impurities-coelute

Radiomatic peak integrations of peaks representing <2.5% of peaks in a chromatogram were variable; therefore, minimum and maximum range data are valid as estimates only and represent the lowest and highest observed percentage of dose in individual patients. Ranges are more reliable for metabolites representing >2.5% of dose (CPT-11, SN-38, APC and SN-38 glucuronide).

  • 4-a The number of patients that had a measurable radioactive peak for this metabolite or impurity, compared with total number of patients.

  • 4-b Peak designation in Lokiec (1996).

  • 4-c Peak designation in Dodds (1997).

  • N.D., not done, only patient 5 was bile-exteriorized.