In this dataset it means filings whose claims combine a topical delivery mechanism (transdermal patch, reservoir, matrix system) with a method for testing or demonstrating its performance — in vitro permeation testing, topical bioequivalence, release-rate measurement, membrane selection, or the sampling and statistical protocols regulators use to judge batch variability. It is a narrower category than dermatology or transdermal delivery generally: it is specifically about proving that a product performs as intended, not just formulating it. That framing is why A61K (medicinal preparations) appears in over 91% of records — the testing method claims are usually attached to a formulation claim.

The dataset ranks 100 assignees by record count, with a clear leader holding 255 records against 36 at fifth place and 18 at tenth — a steep drop-off rather than a gradual one. The top 5 combined account for 41.5% of all 1,109 records in scope, and the top 10 for 51.6%. Beyond the ranked leaders, filing activity spreads into a long tail of companies with single-digit record counts, typical of a field with a dominant core and many peripheral entrants.

Over the only span that can currently be treated as complete, 2021 to 2024, filings grew 6%, from 52 to 55 records. Filing counts for 2025 and 2026 appear lower in the raw data, but that reflects the roughly 18-month lag between when a patent is filed and when it publishes, not an actual drop in activity. The field’s peak filing year to date was 2018, at 89 records, and volumes since have settled into a steadier band rather than a sharp decline.