[sdpd] Powder diffraction and pharmaceuticals

[emilio.tedesco...@pharma.novartis.com]

Dear all,

if I may enter in the discussion raised by L. Mollica, to which Armel added
some provocative statement, I think the question here is not how many
powder pattern from organic compounds/drug substances are present or not in
the ICDD. Pharma industries don't use PXRD to identify known components,
known phases. They rather develop their own compounds, for which PXRD is
one of the main characterization tools in the solid state (despite what
Armel said), particularly when the drug substance is in development.

>From my experience, the pharmaceutical sector is fully aware of what SDPD
can offer, because the crystallisation stage can be difficult, thus the
single crystal technique is not always viable for all the compounds, and
polymorphs and solvates present. This interest is so great that has
prompted, for instance,  'Consortia' like the one we belong to, promoted by
Accelrys, called Molecular Crystallisation, in which programs for SDPD like
PowderSolve are developed (I don't want to start any discussion on
commercial software etc., it's just an example).

The fact that few crystal structures of drug substances determined from
PXRD are available is understandable because industries do NOT want to
publish them, for obvious reasons, not necessarely because they are not
aware of SDPD.

Talking about the Rietveld technique, my impression is that it has not been
fully exploited in the pharmaceutical sector for quantitative issues like
limit of detection of polymorphic mixtures and amorphous determination , as
far as publications are concerned.

yours

Emilio Tedesco


 

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