By Richard Jotcham, Director, Axess Technologies

There are a vast number of different authentication and tracking technologies available today. It is therefore possible to find the most appropriate technology mix and solution for each individual company’s requirements. This article will review examples of the more prevalent developments in authentication and tracking technologies that may be used to protect pharmaceutical products and packaging.

Authentication

Authentication may be separated into three specific categories:

Overt security features are apparent and visible and do not require additional readers or instruments to detect them. The general public or untrained personnel can often verify them.

Examples of overt authentication features include:

• Optically variable coatings that change color when the viewing angle is changed.
  
  
• Specialist print and coatings directly applied to tablets and capsules.
  
  
• Holographic foils attached to packaging, labels and tamper-evident seals.
  
  
• Tear tapes and overwrap containing printed, colored or optically variable effects.
  
  
• Thermochromic inks and coatings that decolorize on warming.
  
  
• Perforations, embossings or watermarks.

Covert features are concealed, they are not immediately apparent and may require a relatively simple reader or verifier (such as a UV lamp or magnifier) to locate and identify them. They represent the second line of defence against counterfeiters and are often ignored by the criminals, who may not realize they are present or find them too difficult to reproduce. These features are particularly useful to company investigators so long as they are kept fully informed of what they should be looking for and are trained to use the readers and testing kits.

Examples of covert authentication features include:

• Microscopic particles of specific colors or colored layers.
  
  
• Tiny planchettes or narrow threads containing micro-text.
  
  
• Labels printed with color combinations or line structures that will not resolve on a normal scanner or color copier.
  
  
• Holograms containing microtext that is only readable under magnification.
  
  
• Inclusions or print containing materials with characteristic spectroscopic properties that are either activated and authenticated visually or detected using a dedicated verifier.

Forensic level authentication may involve the chemical identification of a particular component within the product such as an active ingredient or a particular binder or excipient. Forensic level features are extremely covert and are often present on a ‘need to know’ basis only. They may comprise the addition of unique taggant material where the quantity of taggant is so small that it cannot be detected using available analytical techniques and requires a specific test method to determine its presence. These taggants are added during the manufacturing of the product or packaging, but they will require regulatory approval.

One of the main benefits of forensic level tagging is that it can provide unequivocal evidence that a seized product is or is not genuine. This information can be very valuable in the prosecution of counterfeiting cases where the counterfeit products and packaging are very similar to the genuine article.

Examples of forensic level authentication features include:

• Paper and packaging containing ppm levels of a taggant that is undetectable by conventional analysis but may be extracted and identified using a dedicated test procedure.
  
  
• Identifying the isotopic composition of naturally occurring materials providing information about the authenticity and source of the material.
  
  
• Infra-red analysis compared against a library of spectra held on a database.
  
  
• Elemental analysis using X-ray fluorescence.
  
  
• Additions of DNA fragments to products and packaging.

Authentication features may be combined with a wide range of substrates, carriers and application processes. These can include direct application into packaging -- films, metals or glass -- as an integral part of the material. Alternatively, they may involve an addition to material such as foil, adhesive or ink that is subsequently applied to the substrate.

There are a wide variety of taggant systems, both covert and forensic. It is often confusing and difficult to distinguish these systems. The following paragraphs have therefore been included to provide a brief overview of this area:

Spectroscopic taggants can comprise inks that may be UV absorbers, emitting in the visible spectrum or upconvertors that are irradiated by IR and emit in either the near IR or visible spectrum. More complex spectroscopic taggants make use of particular properties of the emitting substance such as the spectral decay rate, which is measured using bespoke detectors. Spectroscopic taggants may also be incorporated into particles, fibres, planchettes or security threads which are embedded directly into paper or packaging.

Biological taggants may include strands of specific DNA or the addition of chemicals that use biological techniques in their verification. For example, one company has developed a technique of producing monoclonal antibodies of particular molecules. A very low concentration (parts per million) of the taggant is dispersed throughout the product or packaging. In order to verify its presence a small sample is taken and the taggant extracted, a few drops of which are subsequently placed onto a lateral flow device. The liquid flows up the slide and comes into contact with the monoclonal antibody. If the taggant is present then a visual indication appears on the lateral flow device.

Chemical taggants may involve indicators that are pH sensitive or are detected using precise analytical techniques such as IR spectroscopy or X-ray fluorescence. Here a measure of the concentration of the taggant may be made indicating if the product has been tampered with or diluted.