Global patent landscape of synthetic drugs for melasma (2015–2025): innovation trends, mechanistic shifts, and translational challenges

INTRODUCTION: Melasma is a chronic and highly recurrent hyperpigmentation disorder with substantial psychosocial burden and limited long-term therapeutic control. Because current treatments remain largely centered on conventional melanogenesis inhibition, a patent-based review is needed to clarify how synthetic drug innovation is evolving and whether emerging technologies address unmet therapeutic needs. AREAS COVERED: This review analyzed global patent activity from 2015 to 2025 related to synthetic drugs for melasma. A structured search was conducted in the Espacenet database using the keyword 'melasma' and IPC code A61Q (cosmetic and dermatological preparations). After systematic screening, 17 patent filings were included. The analysis focused on geographic distribution, temporal trends, technological strategies, delivery systems, and mechanisms of action. Most patents (94.1%) were based on reformulation strategies, including novel delivery systems and combinations of existing compounds, while only one described a new chemical entity. EXPERT OPINION: The current patent landscape reflects a predominance of incremental innovation, with limited exploration of disruptive strategies. Future advances will depend on targeting pathways beyond melanogenesis and overcoming key translational barriers, including delivery efficiency, safety, and scalability.