Chemistry and Pharmaceuticals Searching Best Practices

Some technical disciplines require deviations from traditional text and classification search approaches. Chemistry and pharmacology searching is one of the best examples. The problems unique to searching for chemical compounds became apparent as early as the 1960s; to address them, professional indexing companies such as the Chemical Abstracts Service (CAS) and Derwent Ltd. began to produce specially created data files geared towards chemical searchers. This article discusses the special treatment that chemical information receives in the patent world, and the tools and training needed to conduct a thorough search for novel chemical compounds, and pharmacology formulations of known drug compounds.

Substance Searching – Names, Numbers and Physical Properties
To the uninitiated, the most obvious way to search for a chemical compound in a patent document is to perform a search on its name. Unfortunately, even according to standards set by international organizations such as the International Union of Pure and Applied Chemistry (IUPAC), a chemical compound may have more than one correct, official name. Pharmacological compounds may be referred to by IUPAC chemical names, common names, and brand or product names and may also have pre-clinical laboratory designations. Identifying all the possible names a chemical may have is one major obstacle in a chemical search; fortunately, this can often be overcome by searching a compound’s CAS Registry Number, a 10-digit number assigned, by the Chemical Abstracts Service (CAS), to a known compound as a unique identifier of that material.

CAS Registry numbers are useful when searching in a CAS-produced database, such as REGISTRY, CAplus (patents and literature), or MARPAT, because all records in these files are intellectually indexed by the CAS staff with the appropriate compound numbers. In addition, performing an initial search using the CAS Registry number can illuminate common names and synonyms for a compound, which are listed in the REGISTRY file, a kind of “chemistry dictionary” which contains structure and physical property data for novel compounds that are published in patents or scientific journals. CAS Registry numbers are often used in technical documents to refer to the precise forms of the chemical compounds they mean to discuss. They represent an effective way to search on a known compound without having to account for potential variations in the name of that substance.