The occurrence of surface delamination in glass vials used to store parenteral drug products is an ongoing problem in the pharmaceutical industry. McCrone Associates has a variety of techniques at its disposal for the characterization of particulate generated by delamination, as well as for the examination of glass surfaces that have been subject to chemical attack resulting in, or potentially leading to delamination.
Visual inspection of pharmaceutical vials can often detect the distinctive appearance of delamination flakes. Isolation of visible and sub-visible particulate is accomplished by filtration in our ISO CL5 cleanroom. Particulate on a filter can be visualized and photographed under a low power stereomicroscope or a higher magnification compound microscope equipped with episcopic (coaxial) illumination. Suspected glass delamination flakes can be removed from filters and mounted for confirmatory chemical analysis by infrared microspectroscopy and scanning electron microscopy with energy dispersive X-ray spectrometry. Our cleanroom staff of particle isolation experts can prepare even minute amounts of material for characterization.
The interior surfaces of glass vials can also be examined using a light microscope equipped with episcopic illumination, to determine which areas have undergone delamination or pitting (preliminary to delamination), and which areas are unaffected. Areas of chemical attack on the inner walls of glass vials can also be imaged using one of our scanning electron microscopes. Elemental analysis and depth profiling of areas of attack can be performed on glass surfaces using our Phi Quantum 2000 X-ray photoelectron spectrometer.
Our JEOL JEM-3010 transmission electron microscope (TEM) can be used for high resolution imaging of glass delamination flakes. Energy dispersive X-ray spectrometry in the TEM provides chemical analysis of thin glass delamination flakes and secondary products formed by reaction of glass with drug products. TEM electron diffraction identifies material as amorphous or crystalline, and provides crystalline phase identification.
Projects involving the isolation and characterization of glass delamination may be quite complex, involving a variety of analytical approaches and testing methods. We recommend that clients interested in this type of analysis contact one of our project scientists to discuss the most appropriate methods to meet their needs, as well as potential costs and expected turn-around time for the required analysis.
Essentials of Polarized Light Microscopy and Ancillary Techniques by John Gustav Delly has been published.
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