Patent ID: 8039220

Claim:
A method for quantifying the amount of busulfan in a human biological fluid sample comprising carrying out an immunoassay of said sample with an antibody, which is selectively reactive with busulfan and is not substantially cross-reactive with tetramethylene sulfone, tetrahydrothiophene and tetrahydrothiophene-3-ol-1,1-dioxide, said immunoassay being carried out to obtain a measured result which corresponds to the amount of busulfan in said sample binding with said antibody, providing a plurality of standards, each standard containing a different predetermined concentration of an amide of the formula: subjecting said standards to the same antibody immunoassay as said sample to obtain results which correspond to the amount of amide of formula II in each of said standards binding with said antibody, comparing said measured result obtained from the immunoassay of said sample with the measured results obtained from the immunoassay of said plurality of standards and quantifying the amount of busulfan in said sample by means of said comparison.