[Validation of the HPLC method in the determination of dioxopromethazine and phenylephrine in eye drops]. / Validácia HPLC metódy pre stanovenie dioxoprometazínu a fenylefrínu v ocnej instilácii.

The present paper introduces a rapid HPLC method for the determination of dioxopromethazine and phenylephrine in eye drops. The method uses a modified C18 stationary phase optimized for the separation of basic compounds and a methanol/1.5 mM phosphoric acid (60/40 v/v, pH 3.02) mobile phase. The flow rate is set to 2 ml/min, sample volume 20 microliters, and compounds are detected at 275 nm. Prior to analysis, the eye drops are diluted with water in a ratio of 1:50. The elaborated HPLC method and the chromatographic system were validated according to the procedure for the validation of chromatographic systems and methods.

Determination of chlorpromazine and thioridazine by differential pulse voltammetry in acetonitrile medium.

This work describes optimal conditions for the determination of chlorpromazine and thioridazine by DPV, with a detection limit of 4.0 x 10(-7)M (0.16 microg/ml). The well-defined peaks indicate that direct measurement in a medium of 0.03 M perchloric acid in acetonitrile is possible and the use of DPV is advantageous when small amounts are to be determined. The sample procedure for pharmaceutical tablets is simple and fast. The method is useful for control of the quality and purity of phenothiazine drugs. The possibility of using numerical analysis to resolve composite signals of the compounds studied has also been demonstrated.