Development of a Competitive Time-Resolved Fluoroimmunoassay for Paclitaxel

Paclitaxel (Tax) is a diterpene alkaloid isolated from Taxus species and has proved clinically effective in treating a number of malignancies. Current quantitative analytical methods for Tax such as high-performance liquid chromatography (HPLC) often involve complicated sample preparation procedures with low recovery rates.

To establish a rapid and sensitive time-resolved fluoroimmunoassay (TRFIA) for measuring Tax in Taxus materials with convenient sample preparation and a high recovery rate.

Rabbit anti-mouse IgG was coated onto a 96-well microplate, which was then incubated with standard solutions of Tax and anti-Tax monoclonal antibody 3A3. A Eu³⁺ -labelled conjugate of Tax and human serum albumin was used as the tracer. The luminescent system was enhanced with a solution containing 2-naphthoyltrifluoroacetone.

The established TRFIA showed a linear response within the Tax concentration range of 3.2 to 80 ng/mL, with a limit of detection of 1.4 ng/mL. The intra- and inter-assay coefficient of variation of the assay was 9.6% and 9.7%, respectively, with an average recovery rate from spiked samples of 108.5%. Tax contents in Taxus samples were determined using both the established TRFIA system and a previously established enzyme-linked immunosorbent (ELISA), and the results of two assays were well correlated.

This TRFIA system shows a high sensitivity, precision and accuracy for detection of Tax. This assay, which is convenient and less time-consuming, allows rapid analysis of Tax and provides another option for Tax measurement for quality control of Taxus materials and products. Copyright © 2017 John Wiley & Sons, Ltd.