Oral pharmaceutical tablets and capsules frequently contain multiple organic and inorganic excipients in addition to the active pharmaceutical ingredient (API). These ingredients each have a specific function and desired location for optimum performance. For instance, a rapid release product may contain a disintegrant that promotes the release of the API in the stomach.
An extended release product may house the API below more slowly dissolving coatings that allow the gradual release of the drug. Some components may be incompatible with the API or other excipients and therefore are designed to be kept separate in the final formulation.
Understanding such complex formulations requires analytical tools capable of probing the chemistry on the micron- or sub-micron length scale. EAG Laboratories uses Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and Raman spectrometry for these types of investigations.
TOF-SIMS and Raman spectrometry have the ability to identify different organic (and many inorganic) materials while SEM-EDS is an elemental analysis technique only and, thus needs a unique element associated with each material for identification. Thus SEM-EDS has limited ability to distinguish organic constituents.