Fully Automated Equilibrium Solubility Testing

Solubility testing of pharmaceutical products, NCEs and intermediates has become increasingly important earlier and earlier in development. As a consequence the number of candidates requiring measurement is now greater than ever and the traditional one-at-a-time manual method is no longer adequate to cover the workload. The ReactArray? ST Workstation, from Anachem, offers a convenient approach for automated equilibrium solubility testing enabling high quality data to be collected faster, more efficiently and under completely controlled conditions.

Based on proven ReactArray technology used in the majority of pharmaceutical companies around the world, ReactArray ST utilises an industry standard autosampler and a tightly controlled rack which provides 10 individual temperature (-30 to 150 °C) and stirring controlled. A dedicated testing device (patent applied for) housing a spring loaded filter is placed into each study, minimising the potential for cross contamination. A quantitative filtered sample is aspirated from a slurry through the device, automatically diluted and injected onto an on-line HPLC. A benefit of the ReactArray approach is that samples are taken accurately even at elevated temperatures. This is very difficult to achieve by traditional methods which require manual filtration or centrifugation followed by accurate sample extraction under rigorous temperature control to prevent precipitation.

Slurry volumes can be sampled from as little as 350 ml meaning precious material is conserved and more studies are completed on relatively small amounts of compound.

An intuitive wizard guides the user through the setup process allowing methods to be written quickly and on-board error checking means that no run can be initiated which contains potential problems. Each vessel can be programmed to have an individual temperature profile with equilibration periods between set temperatures. On-the-fly reference to a previously collected multi-level calibration leads effortlessly to the generation of bar graphs for single temperature studies or solubility curves for multiple-temperature experiments as shown. Rapid data mining means that the choice of solvent, solvent mixture and/or various buffers that can be practically studied is much wider. This is a vital consideration for the scientist who wishes to choose the right crystallisation or reaction solvent, or to make a selection between crystalline or salt forms.