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 measuremen t of paclitaxel and related taxanes in biological specimens using commercia lly 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 meth od detected paclitaxel in concentrations as low as 0.87 nM and was also eff ective in 20% methanol. This radioimmunoassay is useful for the measurement of paclitaxel and taxanes in biological specimens like culture medium of p aclitaxel-producing microorganisms and may be useful for the measurement of paclitaxel and related compounds in other potential natural sources.