Spectrophotometry was established for quantification of naproxen in selected pharmaceutical preparations, namely: Naproxen (250 mg in tablet, Polfarmex), Pabi-Naproxen (250 mg in tablet, Pabianice), Apo-Naproxen (250 mg in tablet, Apotex), and Naproxen (200 mg in tablet, Aflofarm). Methanolic extracts of studied pharmaceutical preparations were analyzed. Analyses were performed at λ=262 nm.

Naproxen content in investigated drugs are consistent with British Pharmacopoeia recommendations (1993), because naproxen content in the preparation should not be smaller than 95% and larger than 105% of declared value.