Sirius T3 measures dissociation constants (pKa) and oil-water partition coefficients (logP/D) of ionizable drugs and small molecules by potentiometric and rapid UV titration using only microgram-scale samples, with up to 10 co-solvents to choose from. It can be used for high-throughput compound screening in the early drug discovery phase, as well as for pre-prescription screening studies with a high degree of automation. An optional autosampling system is also available for fully automated high-throughput unattended testing. accurate determination of pKa and logP can help select the optimal compound structure for understanding drug dissolution, permeation, and absorption in vivo, as well as assist in the establishment of pharmacokinetic/pharmacodynamic modeling and the control of drug toxicity and side-effects, and reduce the risk of failure at the late stage of drug development.