Video-enhanced DVS polymorph screening

products-servicesParticle Analytical ApS
July 11th 2016

Dynamic vapor sorption (DVS) is a key tool to determine water sorption of pharmaceutical compounds. Conventional DVS is limited to varying humidity (water vapor) and registering consequent weight changes.

However, Particle Analytical’s DVS service offers significant enhancements, including use of video camera to allow real time visual detection of crystalline transformations and capability to use non-aqueous solvents, such as methanol, ethanol and other volatiles.

Features

Particle Analytical uses DVS analysis instruments developed by UK-based Surface Measurement Systems Ltd. (SMS), an acknowledged world leader in sorption sciences.

The SMS DVS instrument is highly sensitive, allowing sorption behavior to be accurately determined on sample sizes smaller than 10 mg, thus minimizing the equilibration time needed. The DVS instrument is fully automated, operating under the control of a dedicated PC and control software package that allows fast set up and running of sorption /desorption experiments. In addition, the DVS Data Analysis Suite, which runs from within Microsoft Excel®, provides a powerful environment for rapid plotting and quantitative analysis of data.

The instrument can select one of any two vapor sources, originating from liquid organic solvents or water held at the same temperature. Dry carrier gas passing through becomes saturated with the solvent vapors. Mass flow control combined with the use of unique real time vapor concentration monitoring allows precise control of the ratio of saturated and dry gas flow. A known concentration of the selected vapor then flows over a sample suspended from a recording ultra-microbalance, which measures the change in weight caused by sorption or desorption of the vapor molecules. These dynamic flow conditions enable the adsorption/desorption processes to be studied very rapidly.

Expertise in deploying this powerful tool is enhanced by Particle Analytical’s own in-house experience in testing and the effects of specific solvents, temperature and vapor pressure variations, etc.

Benefits

Particle Analytical’s enhanced DVS service provides a unique method of varying the polymorphy conditions in a controlled manner in order to induce formation of new crystalline forms. Both temperature and composition of solvents can be varied simultaneously. These capabilities offer significant advantages to researchers and development teams.

Overall, DVS is a unique method in understanding drug behavior in relation to humidity and temperature, e.g should special conditions be used during manufacturing and storage in order to prevent stability problems – such as crystalline transformation or degradation.

In particular, using this enhanced instrument, the ability to see what is happening in real time can speed up development process while the wider range of solvents opens up new potential to identify new polymorphic forms of drug product that might have optimized properties, such as enhanced solubility and dissolution rates.