Determination of naproxen in pharmaceutical preparations by room-temperature phosphorescence. A comparative study of several organized media

Different methods for the determination of naproxen by room-temperature pho sphorescence (RTP) using organized media such as cyclodextrins (beta -CD an d gamma -CD) and micelles (Triton X-100 and sodium dodecyl sulfate) are rep orted. The inclusion complexes formed between both beta- and gamma -cyclode xtrins and naproxen were previously investigated at both acid and basic pH by spectrofluorimetry. In both cases, 1:1 guest-host stoichiometries were e stablished and the corresponding association constants were calculated. Dif ferent systems were examined with the purpose of obtaining phosphorescent e mission from naproxen solutions, and the best signals were obtained when na proxen was in the presence of beta -CD-cyclohexane-Tl(i), gamma -CD-1,3-dib romopropane, Triton X-100-Tl(i) and SDS-Tl(i), respectively. In all cases, sodium sulfite was used as deoxygenator. The use of an inorganic compound ( thallium nitrate) as a heavy-atom source in a cyclodextrin system represent s a novel finding. Surface response optimization approaches were carried ou t to optimize the chemical variables which have an influence on the RTP emi ssion of naproxen. Based on the results obtained, univariate RTP calibratio n methods for the determination of the analyte in pharmaceutical preparatio ns were satisfactorily developed. In one case, the standard additions metho d was applied to a mixture of naproxen and the antibiotic tetracycline.