Improving Productivity using Surface
Analysis
Dr A Swift
Talk will focus on:
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Why use surface analysis
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Pharmaceutical industry
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Medical devices
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Consumer products
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These examples fall into the following
categories, trouble shooting, defending product claims,
settling legal claims, bench marking and baseline R&D.
Tablet problems:
Drug molecule in a tablet was breaking
down in daylight. With ToF-SIMS the parent molecule was
detected in a fresh sample but not when the sample was subsequently
exposed to light. The drug has been broken down by UV interaction.
Similar examples are paracetamol tablets
prepared in Africa have brown staining. The tablets showed
the presence of mineral oil contamination and the presence
of Chloroquine in the drug. The later was only found in
the brown region so the plant had not been thoroughly cleaned
prior to the paracetemol production.
Medical components:
The blood sensors have a active surface
layer which optimises the sensor, the blood needs to reach
the sensor rapidly and evenly. The sensor has a fibre outer
mesh, which is plasma surface, treated with either PET or
another material (PTFE?) that will aid the wetting of the
nylon or PE fibres. These fibres are then coated with an
enzyme active material, which has to be uniformly distributed
across the surface of the fibres.
LLDPE syringes are optimised to have a
good smooth performance and MUST be sterile. However, treating
the syringe to give it a sterile surface can reduce the
smooth operation of the syringe during operation. The materials
can be studied in detail using XPS and ToF-SIMS.
The syringes are treated using Gamma radiation,
which oxidizes the surface of the syringe destroying the
lubricant on the surface of the syringe. Long-term storage
of the treated syringes also shows areas of concern. The
drug stored in the syringe diffuses into the syringe surface
and starts to reduce the level of the active ingredient
in the drug.
Consumer industry products:
Textile products need modification in order
to give them long life. Different natural fibres require
different treatments since they have different surface chemistries.
The claims of so-called gentle bleaches such as Vanish can
be shown scientifically using SIMS to clean the surface
without damaging the surface of the fibres. The removal
of contamination
and fingerprinting exercises using static SIMS can see the
retention of surface coating of the fibres.
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