Validated high-performance liquid chromatographic assay for simultaneous determination of dacarbazine and the plasma metabolites 5-(3-hydroxymethyl-3-methyl-1-triazeno)imidazole-4-carboxamide and 5-(3-methyl-1-triazeno)imidazole-4-carboxamide.
Dacarbazine (DTIC) is a prodrug that is clinically effective in the treatment of Hodgkin's disease, melanoma and soft tissue sarcoma. To better characterize the clinical pharmacology of parent drug and reactive metabolites, a reversed-phase HPLC method with UV detection was developed for simultaneous determination of dacarbazine and the metabolites 5-(3-hydroxymethyl-3-methyl-1-triazeno)imidazole-4-carboxamide (HMMTIC) and 5-(3-methyl-1-triazeno)imidazole-4-carboxamide (MTIC). Chromatographic separation was achieved with a Zorbax SB-CN column and with a mobile phase of 80% 50 mM ammonium phosphate, pH 6.5, 20% methanol and 0.1% triethylamine. HMMTIC, MTIC and DTIC were extracted from plasma with methanol precipitation of the proteins. Recovery of DTIC and the metabolites from whole blood was greater than 92%. Rapid processing of whole blood, methanol extraction and storage at -70 degrees C substantially increased the stability of HMMTIC and MTIC from less than 15 min to 3 days. Precision for HMMTIC, MTIC and DTIC ranged from 3.7 to 16.3% relative standard deviation. The accuracy ranged from 101 to 114% for all three analytes. The validated assay was used to determine the pharmacokinetic data for dacarbazine and its active metabolites for human patients with recurrent glioma receiving DTIC intravenously.
Safgren
S L
SL
Department of Oncology, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Reid
J M
JM
Rios
R
R
Ames
M M
MM
D002851:Chromatography, High Pressure Liquid; D017322:Clinical Trials, Phase II as Topic; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000032:analysis* / Q000097:blood* / Q000493:pharmacokinetics; D004355:Drug Stability; D006801:Humans; D008956:Models, Chemical; D015203:Reproducibility of Results
C027169:5-(3-hydroxymethyl-3-methyl-1-triazeno)imidazole-4-carboxamide; D003606:Dacarbazine; C010243:5-(3-methyl-1-triazeno)imidazole-4-carboxamide