Quantitation of antihistamines in pharmaceutical preparations by liquid chromatography with a micellar mobile phase of sodium dodecyl sulfate and pentanol

A reversed-phase liquid chromatographic procedure with a micellar mobile ph ase of sodium dodecyl sulfate (SDS), containing a small amount of pentanol, was developed for the control of 7 antihistamines of diverse action in pha rmaceutical preparations (tablets, capsules, powders, solutions, and syrups ): azatadine, carbinoxamine, cyclizine, cyproheptadine, diphenhydramine, do xylamine, and tripelennamine. The retention times of the drugs were <9 min with a mobile phase of 0.15M SDS-6% (v/v) pentanol. The recoveries with res pect to the declared compositions were in the range of 93-110%, and the int ra- and interday repeatabilities and interday reproducibility were <1.2%. T he results were similar to those obtained with a conventional 60 + 40 (v/v) methanol-water mixture, with the advantage of reduced toxicity, flammabili ty, environmental impact, and cost of the micellar-pentanol solutions. The lower risk of evaporation of the organic solvent dissolved in the micellar solutions also increased the stability of the mobile phase.