for Triciribine and Triciribine Phosphate. Ive had a difficult time developing this method. At this point it appears that the chromatograpahy (peak shape and no interference) is good but the concentrations for both drugs are very erratic (non-reproducibile) in the standard curve. Im using 5'FDUR as the internal standard and its CV for about 30 samples is 6. This leads me to believe it is a solubility issue for TCN and TCNP. I tried several different solvents to dissolve the drug in and settled on DMSO for both and just dilute that with water to create my working solutions to spike the plasma with. Could this be a problem? Should I go with a different solvent for the stock solution?

Im also using 200 ul of cold ACN containg IS to 200 ul of plasma, vortexing, centrifuging and aliquoting 200 ul for evaporation under nitrogen with the water at 40 degrees celsius and reconsitituting with 30 ul of mobile phase and injecting 20ul. Another problem might be mobile phase. Im using 0.06% TFA (pH 2.5) and ACN, isocratically at 94%/6%, respectively. I was using 0.1% Formic Acid and ACN at the same isocratic percentages but it did not give the same sharp peaks, especially for TCNP that TFA gave. The column is Supelco Discovery RP Amide C16. Any and all help or commments would be greatly appreciated. -tim