Objective: To establish an HPLC method and a non-aqueous titration for the determination of piperazinylethylestrone drug substance, and an HPLC method for the determination of piperazinylethylestrone in dog plasma.
Methods: Anhydrous acetic acid as solvent, 0.1 mol/L perchloric acid as titrant, crystal violet solution as indicator to establish non-aqueous titrations and ODS column as stationary phase, methanol and a mixture of 0. 025 mol/L sodium phosphate monobasic and 0.02 mol/L sodium dedecyl sulfate (80:20) [adjusted with phosphoric acid to a pH (4.8 +/- 0.1)] as mobile phase, 220 nm as detective wavelength to establish HPLC-UV method for determination of piperazinylethylestrone drug substance; FMOC-CL as a derivatization reagent, FD as a detector to establish an HPLC method with derivatization and column switching for determination of piperazinylethylestrone in dog plasma.
Results: The RSD of non-aqueous titrations within-day and between-day were 0.28% and 0.21%, respectively; the established HPLC-UV method had good linearity and precision within the range of 1.001-5.005 microg of piperazinylethylestrone, the detection limit was 4 ng (S/N=3); the linearity of HPLC method with derivatization and column switching was within the range of 8.4-420 ng/ml, the detection limit was 1 ng (S/N=3). The clean-up recoveries were from 77.24% to 83.10%, and the method recoveries were 98.33%-103.3%. The RSD of within-day and between-day were less than 7.7% and 7.3%, respectively.
Conclusion: The above three methods are simple, accurate and precise for the determination of piperazinylethylestrone drug substance and for the determination of piperazinylethylestrone in dog plasma.