Semantics of Insulin

The lack of a stringent terminology and a well‐defined vocabulary for insulin and related subjects has been a deterrent to solving many of the problems encountered when using insulin in pumps. The same word is sometimes used to describe a number of different phenomena or the same phenomenon is referred to by different words. Thus the word ‘insulin’, meaning the substance, the protein hormone, is commonly used as a synonym for an ‘insulin formulation’ for the treatment of diabetes. The ‘insulin dimer’ can be the covalent or the non‐covalent dimer, two very different substances. ‘Isoelectric precipitation’ is often mistaken for ‘fibrillation’ and both are referred to as ‘aggregation’ or ‘polymerization’. The word ‘crystal’ is being used as a synonym for ‘particle’, and determination of ‘the content of insulin’ by HPLC is sometimes called a ‘bioassay’. The nature and consequences of these pitfalls are discussed, and advice is given on how to avoid them.