Chris Simpson, a founding director of Interactive Coding Equipment (ICE), looks at how the latest generation of thermal transfer overprinters can take an active role in preventing coding errors
Accuracy in pharmaceutical package coding is a legal and commercial necessity. It is no exaggeration to say that the tolerance for error is zero, especially where permanent harm or death can result from mistakes. Yet preventing this disastrous outcome is expensive. For many years, coding and labelling errors were the cause of more than 50% of product recalls in the US, at a typical cost of between US$2-50m per recall, in addition to the loss of reputation, customers and sales.
Automatic inspection systems such as online character recognition (OCR) are often used to detect package and product coding errors but, as the associated risks and costs continue to rise, it is increasingly necessary and more cost-effective to focus on prevention rather than cure.
The march of technology has seen electro-mechanical coders replaced with digital coding equipment, yet the majority of package coding kit is still set up manually, and this is where most coding errors happen. Nobody is perfect; human error is inevitable even in the most experienced, attentive operator. The simplest mistake necessitates expensive on-line inspection systems and costly reworking of product - yet the correct choice of coding equipment can help avoid this.
For example, the most common items to be overprinted are date codes such as MAN DATE and the EXP DATE where it is all too easy to transpose digits or enter incorrect data. Yet the selection of a printer that incorporates a simple calendar picker for standard date input makes the process entirely logical and eliminates the opportunity for invalid dates (e.g. 31 FEB). This also means that, irrespective of language, operators can enter the data in a format they understand; once the date is selected, the coder can overprint in the chosen language or indeed multiple languages. Password protection ensures only authorised users can change printer set up or the message.
It is possible to define a date input range for each product template. For example, where a particular product has a life of two years and is always packed within 21 days of manufacture, the template will permit only a MAN DATE within 21 days prior to packing, and an EXP DATE of between 709 and 730 days. Some coders require only the MAN DATE to be input, with the EXP DATE automatically calculated from this.
The latest thermal transfer overprinters also offer pre-defined templates, further restricting the potential for costly mistakes. For example, if the Lot Code is a six-digit numeric code, the input field is masked so that the operator can enter only numerical data. It will not eliminate the need for inspection systems but will focus on prevention to ensure accuracy and reduce operating costs.
Vision inspection systems are inevitably subjective: when is the print good enough and when is it not? A significant cost is often the "false reject" - products with print that would be legible to the consumer but where vision systems must "play safe" and reject them. In this area too, thermal transfer overprinters can help.
Thermal transfer provides a more consistent print than traditional hot stamp coders, where code is created using individual character type-blocks; a misaligned or worn character produces inconsistencies. It is arguable whether this reduces the print quality to the human eye but most OCR equipment will reject it. Thermal transfer technology eliminates this unnecessary cost through consistently legible print and a range of typefaces that includes dedicated OCR fonts, designed to improve the distinction (and thus reduce any possible confusion) between characters for more reliable OCR inspection.
The use of thermal transfer is likely to expand with the increased drive for product traceability or anti-counterfeit information. Top-end printers can overprint all common industry barcodes including Code39, Code128, GS1-Databar (Reduced Space Symbology (RSS)) and GS1-Datamatrix. For example, a Datamatrix (2D) barcode can be used to print product information (e.g. NDC number) and can include Lot Number and Expiration Date, as well as e-Pedigree traceability codes. In the future, these codes may be scanned at the point of dispensing - in some cases, at the bedside. If there is a chance that information has been printed incorrectly during manufacture the consequences could be dire.
Thermal transfer is a logical choice for many coding applications in pharmaceuticals. Not only because it can print real-time and unique traceability codes, but also because it can eliminate operator error and reduce risk in the everyday coding of essential information.