Development of Turbidimetric Methods for the Determination of Some N-Substituted Phenothiazine Derivatives Using Sodium Dodecyl Sulfate and Mercury(II) Chloride

Abstract

Two turbidimetric procedures were developed for the determination of Fluphenazine·HCl (FPH), Chlorpromazine·HCl (CPH), Thioridazine·HCl (TH), and Trifluophenazine·2HCl (TFPH) in several pharmaceutical preparations using sodium dodecyl sulfate (SDS) (method A) and HgCl2 (method B) as precipitant reagents. Method A is based on the sparingly soluble ion-association complex formation between protonated phenothiazines and SDS. In method B, HgCl2 is reduced to insoluble Hg2Cl2 in the presence of phenothiazine derivatives. The Beer's law in method A was obeyed over the range 30–71.5, 14–106, and 8–57 µg mL−1 for CPH, FPH, and TH, respectively. TFPH, CPH, and TH were determined using method B over the range 14.4–191.7, 17.7–106.6, and 1–8.1 µg mL−1, respectively. The proposed methods are simple, fast, precise, economical, and applicable for the determination of selected phenothiazine drugs in formulations at a wide concentration range without any considerable interference.