mPGES-1 is a promising target for development of new anti-inflammatory drugs. We aimed to create mPGES-1 inhibitors by modifying the structure of NSAIDs by replacing the carboxylic acid functionality by sulfonamide moieties. Compounds were also tested for 5-LOX inhibition. The most potent mPGES-1 inhibitor was lonazolac derivative 22 (IC₅₀ = 0.16 μM), while the best 5-LOX inhibition was attained by indomethacin derivative 17 (IC₅₀ = 0.9 μM). Inhibition of COX-1 activity was completely removed.