A radioimmunoassay for the measurement of paclitaxel and taxanes in biological specimens using commercially available reagents

We have developed a rapid and sensitive radioimmunoassay for the measurement of paclitaxel and related taxanes in biological specimens using commercially available reagents. The presence of paclitaxel competitively inhibited the binding of radioactive paclitaxel to polyclonal anti-taxane antibody or anti-taxane monoclonal antibody. When using polyclonal antibody, this method detected paclitaxel in concentrations as low as 0.87 nM and was also effective in 20% methanol. This radioimmunoassay is useful for the measurement of paclitaxel and taxanes in biological specimens like culture medium of paclitaxel-producing microorganisms and may be useful for the measurement of paclitaxel and related compounds in other potential natural sources.