PharmPrep media are a new line of spherical silica
sorbents from EMD Chemicals which have been designed for use in process chromatography in
the pharmaceutical market. The pharmaceutical market is a specialised market requiring
high quality, highly consistent and highly productive products from reliable sources of supply.
To this end EMD Chemicals has designed a new family of products to address these specific requirements.
The first product to be made available is PharmPrep CC for
preparative chromatography, a spherical, totally porous Silica Gel manufactured by a
large-scale process from water glass (sodium silicate solution) and sulfuric acid to produce a
large particle size spherical product.
Spherical materials have the following advantages for classical open column chromatography:
They are easily packed into columns, they have high bulk densities, which results in good
loadability and furthermore, they exhibit low backpressures, allowing for fast elution.
Until recently spherical materials were mostly manufactured as small particles and in small
batch sizes for use in High Performance Liquid Chromatography with very limited availability
for process applications.
With PharmPrep CC comes the possibility of using a spherical sorbent for performing process
chromatography at any scale and at a reasonable cost. PharmPrep CC is the ideal media for
high quality high performance separations at the true process scale.
PharmPrep CC media properties
| |
Mean Pore Size [Å] |
60 |
| Specific Pore Voume (ml/g) |
0.74 - 0.84 |
| Specific Surface Area (m2/g) |
~500 |
| Bulk Density (g/ml) |
~.055 |
| Loss on Drying (%) (150°C) |
>2% |
| Surface pH (10% aq. suspension) |
6.5-7.5 |
| Iron Content (%) |
0.008 |
PharmPrep Characteristics
Spherical, totally porous particles
Easy packing of efficient columns without additional apparatus.
High bulk Density
Higher loadability when compared to irregular Silica Gels. Increased loadability means greater throughput and
better process economics.
Mechanical Stability
Enables high flow rates in packed columns and low fines generation. This
results in excellent throughput and minimal need for repacking due to particle
degradation and frit clogging.
Sixty (60) Å pore size
Good accessibility for molecules below 1000 Dalton coupled with high surface area for maximum
loadability of the media
Excellent powder flow characteristics
PharmPrep media flows very well with extremely low dusting, so simple, gravity dry packing of
columns produces, reproducible, high efficiency columns, cleanly with minimal exposure to Silica
dust as the time require to consolidate the bed is minimized by the flow characteristics of the
material.
High permeability of packed columns
The columns produced with PharmPrep materials exhibit high permeability compared with columns
produced from competitive materials of comparable particle size distribution.
Fig. 1: Solvent flow through a packed bed in Open Column Chromatography
5g of each sorbent have been dry packed into a glass column. 50ml of ethanol are passed
through the columns by gravity flow. The weight of the effluent is automatically measured
and the time required for the total amount of solvent to pass through the columns is recorded.
PharmPrep CC saves substantial time due to its reliable and efficient behavior under
gravity conditions in open columns. |
 |
The selectivity features of PharmPrep CC in comparison to LiChrospher®
(15µm) can be illustrated using the following examples:
Fig. 2: Separation of a synthetic diastereomeric mixture on
LiChrospher®, 15 µm (Fig. 6a) and
PharmPrep® CC, 40-63 µm (Fig. 6b).
The selectivity of the two sorbents is comparable, while the resolution for PharmPrep®
CC (40-63µm) is reduced due to its coarser particle size. |
 |
Fig. 3: Separation of Tocopherol isomers from sunflower oil on
LiChrospher, 15µm (Fig. 7a) and PharmPrep CC, 40-63µm (Fig. 7b).
The selectivity of the two sorbents is comparable, while the resolution for PharmPrep CC
(40-63µm) is reduced due to its coarser particle size. |
 |
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