Driving home from a Serialization conference, I started to think about Entropy and the randomness of serialized numbers. In the EU Directive 2011/62, the unique identifying numbers must be random, non-sequential and unique. They also must have some ‘entropy’, or a lack of predictability about them.
I had not thought about ‘entropy’ much these last thirty years since studying thermodynamics at the Worcester Polytechnic Institute. In thermodynamics, entropy was defined as ‘a thermodynamic quantity that changes in a reversible process by an amount equal to the heat absorbed or emitted divided by the thermodynamic temperature.’
Entropy and the second law of thermodynamics explained why ice melts and was used to support the Big Bang and Expanding Universe Theories. It describes the universe’s tendency towards chaos and disorder. It is amazing how it became part of the serialization glossary - yet almost counter-intuitive. Regulations have been using words like stability, repeatability, consistency and predictability as requirements for pharmaceutical processes and facilities; now, entropy and the disorder it achieves is now part of the regulations.
I believe that another law, the Law of Conservation of Mass, is also worth considering to be included in the glossary of Serialization terms. This ‘law’ states that the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. In other words, stuff going into a pipeline equals the stuff coming out at the other end.( After using this principle in process plants in the real world, most engineers have added the exception: ‘Except if it gets stuck in the middle, or leaks out along the way!!’)
This principle works just as well when we look at product pipelines as well as chemical reactions and piping systems. What is manufactured equals what is sold, unless it is stolen, gets lost in the corner of some warehouse or shipping depot, or if criminals add counterfeit stuff into the supply pipeline.’
With much fanfare and publicity, Serialization came about to address the counterfeiting concerns of Industry and thwart any criminal attempts of adding fake products to the pipeline. But, we must not forget the other benefits that serialisation can provide.
In my next blog, I will discuss where “leaks” can occur and how to minimize them. I look forward to sharing my thoughts more with you next week!
Michael J Shea
Director of Engineering, GxP Systems