How DSC makes light work of optimizing
process development and manufacturing.
Biopharmaceutical products are extracted
and purified from mammalian cell lines
during process development and
manufacturing under conditions where the
protein drug remains active and stable
for its full shelf life. During
downstream process development and
manufacturing there are several steps
which can stress the protein, so it's
important to monitor it to ensure the
process does not affect its structure,
function or stability, or any changes to
the process do not adversely affect the
protein drug product. The final drug
product is packaged in syringes or vials
for distribution. The drug product is
also tested to ensure that different
lots are a highly similar in critical
quality attributes. Lots from different
manufacturing sites are also compared to
make sure they are highly similar. During
process development the different
conditions used during purification, such
as acidic buffers for viral inactivation,
are evaluated and optimized. This enables
identification of the most effective
process to maintain protein stability
and minimize protein aggregation. Thermal
stability characterization by
differential scanning calorimetry, or DSC,
is used during process development and
manufacturing. DSC measures the proteins
thermal transition temperature, or TM. For
reversibly denatured proteins the TM is
the temperature at which 50% of the
protein is native and 50% is denatured.
Higher TMs correlate to more stabilizing
conditions. Even if a protein is
irreversibly denatured by heat, TM from
DSC is still useful in rank ordering
stability.
DSC works by measuring the heat change
of protein unfolding during thermal
denaturation. DSC is universally
considered the gold standard for
measuring the TM of proteins in solution.
It quickly and accurately measures the
TMs of the same protein in different
process conditions. The conditions with
the higher TMs from DSC indicates the
conditions for further study and are
used to optimize the process, as well as
reduce manufacturing costs. DSC is
commonly used to evaluate the multiple
TMs of large multi-domain proteins like
antibodies. Beyond the TM, DSC is
information-rich especially when
compared to other techniques such as
fluorescence. This includes T onset, the
temperature where the heat capacity
begins to change. The higher the T onset,
the higher the stability. T 1/2 is width
of the DSC peak. The narrower peaks
indicate more compact protein structures
which frequently result in more
effective formulations. DSC also measures
enthalpy, a measure of the energy needed
to break the non-covalent bonds which
keep the protein folded. DSC is typically
used in comparability studies, comparing
the TM and other DSC parameters for
different lots of protein. When DSC
profiles are identical with an
experimental variability the thermal
stability of the samples are highly
similar. DSC is more reliable than TM
measurements from intrinsic or extrinsic
fluorescence which frequently introduce
unwanted artifacts or unexpected TM
shifts. It's an essential stability
screening tool used throughout
biopharmaceutical development, including
process development and manufacturing.
Choosing the most stabilizing process
condition results in a more successful
drug and more economical efficient
production.
Malvern Panalytical's MicroCAL PEAQ-DSC systems
use small sample volumes, are easy to
operate, can be automated for high
throughput of multiple samples with
solutions available for 21 CFR part 11
compliance. MicroCAL DSC is the trusted
standard at the forefront of global
biomolecule characterization for 40
years. For more information on MicroCAL
DSC and how it can support your research,
please visit malvernpanalytical.com/microcal
or contact your regional Malvern Panalytical
sales office