DETERMINATION OF CETYLPYRIDINIUM CHLORIDE IN PHARMACEUTICAL PREPARATIONS BY SOLID-STATE SPECTROPHOTOMETRY METHOD

Quaternary ammonium compounds, and among them cetylpyridinium salts (CP) in particular, are widely used as antiseptics and disinfectants, for local treatment of infectious and inflammatory processes of the mucous membrane of the throat and oral cavity, as constituents of lozenges, gels and oral hygiene products. This paper proposes conditions for determination of cetylpyridinium chloride, which has an antimicrobial effect, in some surfactant-containing pharmaceutical preparations approved for the medical use, using solid-state spectrophotometry and a test method. Linen fabric (LN) was used as a solid matrix. The paper shows the efficiency of sorption extraction of cetylpyridinium chloride in the form of the ion associate with the organic azo dye sulfonazo (SFN). Analysis of the absorption spectra of solid-state systems [LN-SFN] and LN-[SFN-CP] showed that the reagent was practically not extracted at pH ≥ 4, but in the presence of CP the sorption was observed over the entire pH range studied with the maximum at pHmax = 5. For the proposed test method, the range of determined concentrations of CP was 1.0–16 mg/dm3 and the limit of detection was 0.4 mg/dm3; for the solid-state spectrophotometric determination, the range of determined CP concentrations was 0.5–24 mg/dm3 and the detection limit was 0.2 mg/dm3. The possibility of determining the CP in real objects was demonstrated.