The dataset ranks 100 assignees by record count, with the leader holding 470 records and a steep drop to 205 by fifth place and 106 by tenth. Together the top 5 account for 22.4% of all 6,176 records in scope and the top 10 for 32.5%, which means the majority of filing activity sits outside the leading names in a long tail of smaller filers. This is a moderately concentrated field rather than one dominated by a single player, so a freedom-to-operate review needs to look well beyond the top few assignees.

Filing peaked in 2019 at 451 records and has since declined through the last complete year, 2024, where it stood at 196 — a -31% change from the 283 filed in 2021. Publication typically lags actual filing by about 18 months, so the lower counts shown for 2025 and 2026 are not yet reliable evidence of a continued slowdown; they will rise as more recent filings publish. Anyone using this trend for planning should treat 2024 as the most recent dependable data point.

A61K (medicinal preparations) appears on 66.6% of the 6,176 records and C07D (heterocyclic compounds) on 53.2%, showing that most claims are anchored to drug composition rather than purification hardware itself. C07K, the peptides-and-proteins class, covers only 11.3% of records, and process-oriented classes like B01D (separation processes, 4.1%) and G01N (material analysis, 3.8%) are comparatively thin. Because a single record can carry multiple IPC classes, these shares add up to more than 100%, but the relative gap between formulation chemistry and separation process claims is the notable pattern.