A fully automated instrument for 'gold standard' measurement of pKa, log P/D and solubility using sub milligram sample quantities.

Features and Benefits




Robotics. Fully automated x and y axis on titrator module.

Automation allows you to run complicated assays that would be hard to do manually.

Autoloader. Fully automated x, y and z axis.

The optional autoloader allows users to run unattended experiments on SiriusT3, and provides convenience and high throughput possibilities. 

Assay Expert. Option to integrate software from ACD to analyse structure and identify ionisable groups, identify whether they are acidic or basic and estimate pKa and log P values.

Predicted information helps users to optimise the design of experiments.



Analytical methods. SiriusT3 is intended for analysing pure single-component organic chemicals and their salts. Templates are supplied for all supported assays. Users can save customised templates if required. 1-2-3 template for setting up cosolvent pKa assays.

Ease of use. Many assays work with standard templates.

pKa. Determine pKa values to the highest commercially available accuracy. Results in 15 minutes by Fast UV for most samples. UV-metric method for pKas below 2, above 12. Cosolvent methods for poorly soluble samples. pH-metric  assays for samples without pH/UV activity. Yasuda-Shedlovsky plots for cosolvent pKas. Generate distribution of species plots. Determine buffer capacity. Sample requirement:  UV, 10 μg; pH-metric, 1 mg.

Accurate, measured pKa values are important in many areas of pharmaceutical science.

log P. Determine log P and log D vs. pH. Study partition between water and octanol, toluene, dodecane and with other solvents. Built-in methods for high, medium and low log P. Sample requirement:  1 - 2 mg.

No need for time-consuming shake-flask style experiments in multiple pH buffers. The Sirius pH-metric method provides independent confirmation that ionisation has occurred, and also helps characterise acidic and basic groups.

Solubility. Determine intrinsic solubility and kinetic solubility. Derive pH vs. solubility profile. Determine supersaturation. Sample requirement:  1 -10 mg, depends on solubility.

Sirius methods provide valuable insights, such as learning whether compounds precipitate in LLPS form with the potential for solubility enhancement.

Dissolution with pH control. Microscale methods in 1.5 - 2 mL with temperature control. Miniscale methods in 20-25 mL, without temperature control.

Microscale methods to profile drugs for dissolution and precipitation rates, often using less than 1 mg of compound. Explore the effects of changing pH.



Assay conditions. Assays are performed in solution, 1 - 3 mL. Solutions prepared in vials via automated dispensers and temperature-controlled between 12 - 70°C.

By working in small volumes, SiriusT3 makes measurements using very small amounts of sample.

Getting samples to dissolve. Built in ultra-sonic bath to help dissolve poorly soluble compounds. 10 μL of DMSO can be added to aid dissolution. Acid and base pre-dose can be programmed.

It's really important that samples are dissolved at the start of pKa, log P and solubility experiments.

Clean-up assays. Short automated procedures for cleaning electrode and probes. Low to high and high to low pH with cosolvent present; surfactant wash at end.

Regularly running clean-up assays ensures that SiriusT3 is always "ready to go".

Sample introduction. Powdered samples can be weighed directly into sample vials. Alternatively, stock solutions of samples can be prepared (e.g. 10 mM in DMSO) and aliquots of stock solution can be pipetted into vials.

SiriusT3 makes measurements using very small amounts of sample.