PDF, Patent Landscape Report on Atazanavir - WIPO

US CLASSIFICATION SYSTEMThe US classification system is much older than the International Classification Codes, andis organized quite differently. It is entirely numerical, and each Class has many divisionsthat are organized hierarchically, but the hierarchical numbering is not nested in the waythat the IPC codes are more likely to be. This means that the relatedness oneclass/subclass to another cannot be determined from the numbers themselves, but rathermust be investigated one by one using the code descriptions provided by the US <strong>Patent</strong>and Trademark Office.The most common US codes found in the chemical subcollection are shown in Figure 46.But the numbers after the class designation (first 3 digits), do not convey hierarchicalrelationships. The hierarchical relationships are solely conveyed by the level of indentationunder the primary US Class, as shown in Figure 47.Figure 46 US Codes found in the targeted Chemical CollectionFigure 47 Sample of the classification hierarchy for US Code 546/332Simple Example:52