Moustafa A.A.Hegazy M.A.Mohamed D.Ali O.Cairo UniversityFaculty of PharmacyAnalytical Chemistry DepartmentKasr-El Aini St11562 CairoEgypt; October University for Modern Sciences and ArtsFaculty of PharmacyAnalytical Chemistry Department11787 6th of October CityEgypt Helwan UniversityFaculty of PharmacyAnalytical Chemistry DepartmentEin Helwan11795 CairoEgypt; October University for Modern Sciences and ArtsFaculty of PharmacyAnalytical Chemistry Department11787 6th of October CityEgypt2020-01-092020-01-09201810603271https://doi.org/10.5740/jaoacint.17-0078PubMed ID 28766478https://t.ly/LXrvAScopusThe presence of coloring matters in syrups usually interferes with the spectrophotometric determination of active pharmaceutical ingredients. A novel approach was introduced to eliminate the interference of sunset yellow (coloring matter) in Cyrinol syrup. Smart, simple, accurate, and selective spectrophotometric methods were developed and validated for the simultaneous determination of a ternary mixture of carbinoxamine maleate, pholcodine, and ephedrine hydrochloride in syrup. Four of the applied methods used ratio spectra: successive derivative subtraction coupled with constant multiplication, successive derivative of ratio spectra, ratio subtraction coupled with ratio difference, and ratio spectra continuous wavelet transforms zero-crossing. In addition, a method that was based on the presence of an isosbestic point, the amplitude summation method, was also established. A major advantage of the proposed methods is the simultaneous determination of the mentioned drugs without prior separation steps. These methods were successfully applied for the determination of laboratory-prepared mixtures and a commercial pharmaceutical preparation without interference from additives, thus proving the selectivity of the methods. No significant difference regarding both accuracy and precision was observed upon statistical comparison of the results obtained by the proposed methods with each other and with those of official or reported ones.EnglishOctober University for Modern Sciences and ArtsUniversity for Modern Sciences and ArtsMSA Universityجامعة أكتوبر للعلوم الحديثة والآدابantitussive agentazo compoundcarbinoxaminecodeinecoloring agentephedrineFD & C Yellow No. 6morpholine derivativepholcodinepyridine derivativeanalogs and derivativeschemistrylimit of detectionproceduresspectrophotometryAntitussive AgentsAzo CompoundsCodeineColoring AgentsEphedrineLimit of DetectionMorpholinesPyridinesSpectrophotometryArticlehttps://doi.org/10.5740/jaoacint.17-0078PubMed ID 28766478