Home > Applications > Preparative Chromatography

Purification and Isolation Techniques

Preparative RP-HPLC (Reverse Phase- High Performance Liquid Chromatography) has been increasingly used to provide tens of grams to kilograms of high purity material in pharmaceutical product development. However, even with the development of Flash Chromatography as an alternative, these purification techniques are struggling to cope with the throughput demands that the compounds being developed and requiring purification are causing, primarily due to solubility issues.

By using high performance counter current chromatography instruments, chemists are achieving high purity (>95%) and high crude sample masses per injection at low solvent usage (18 grams of sample injected per litre of solvent usage). The reason for this is that chemists are able to use a liquid stationary phase, which offers far superior loading capacity and the advantage of loading the crude sample in either the mobile or stationary phases or a mixture of the two. These options help eliminate many, if not all solubility issues.

Because of the benefits performance counter current chromatography instruments offer to chemists, it is not surprising these instruments are becoming widely used. Scientists are also finding that as well as being a tool to perform high purity/ high capacity isolations of target compounds, it is very versatile and can be used for the concentration of impurities/trace compounds at starting concentrations as low as 2-5%. It offers a quicker less laborious alternative to the traditional methods of isolating gram quantities of impurities for standards.

Dependent on the scale, Dynamic Extraction's Spectrum (milligram to gram), Midi (tens of grams) or Maxi (kilo) finds applications in this segment.

Below are presented two examples of HPCCC instrument performance on purifications of two materials from pharmaceutical development projects:

Type of separation: Hydrophobic (Non-polar)

Midi HPCCC instrument
Phase system: Heptane/Ethyl Acetate/Methanol/Water
Loading per injection: 25 grams of crude
Target compound isolated per injection: 6 grams (average)
Purity: >92%
Recovery: >95%
Cycle time: 40 minutes
Total quantity of crude processed: 9.0 kg
Total solvent usage: 828 litres

Type of separation: Hydrophobic (Non-polar)

Maxi HPCCC instrument
Phase system: Acetonitrile/Propanol/Water + Ammonium Sulphate
Loading per injection: 160 grams of crude
Target compound isolated per injection: 23.6 grams (average)
Purity: >95%
Recovery: >90%
Cycle time: 40 minutes
Total quantity of crude processed: 6.7 kg
Total solvent usage: 468 litres

Finally, to illustrate the types of crude sample that can be injected directly onto a HPCCC column we have included photographs of two samples with high particulate contamination that were directly injected on to the column without any loss of performance.