Validated HPLC-UV method for simultaneous quantification of PI3K inhibitors, copanlisib, duvelisib and idelalisib in rat plasma: Application to a pharmacokinetic study in rats.

Phosphatidylinositol 3-kinase (PI3K) inhibitors are novel class of anticancer drugs, which are approved to treat various malignancies. We report the development and validation of a high-performance liquid chromatography (HPLC) method for the simultaneous quantitation of three PI3K inhibitors namely copanlisib, duvelisib and idelalisib in rat plasma as per the FDA regulatory guidelines. The method involves extraction of copanlisib, duvelisib and idelalisib along with internal standard (IS; filgotinib) from rat plasma (100 μL) using a liquid-liquid extraction process. The chromatographic separation of the analytes was achieved using step-wise gradient elution on a Hypersil Gold C18 column. The UV detection wave length was set at λmax 280 nm. Copanlisib, duvelisib, idelalisib and the IS eluted at 7.16, 12.6, 11.9 and 9.86 min, respectively with a total run time of 15 min. The calibration curve ranged from 50 to 5000 ng/mL for all the analytes. Inter- and intraday precision and accuracy, stability studies, dilution integrity and incurred sample reanalysis were investigated for all three analytes, and the results met the acceptance criteria. The validated HPLC method was successfully applied to a pharmacokinetic study in rats.