Use of liquid chromatography in pharmaceutical analysis and preparation of monolithic stationary phases for thin-layer chromatography

(EN) In the first part of this work, analytical methods for determination of impurities of active pharmaceutical ingredients (API) in combined pharmaceutical dosage forms were developed and validated. Development of the methods covered both the optimization of sample preparation procedure and chromatographic conditions. The methods were validated according to International Conference on Harmonization guideline and both of them were confirmed to be able to analyze stability samples. Impurities in paracetamol, codeine phosphate hemihydrate and pitophenone hydrochloride in the presence of fourth API fenpiverinium bromide were separated by using ion-pair reversed phase chromatography with gradient elution. Symmetry C18, 250 x 4,6 mm, 5 µm heated to 35 řC was used as a separation column. A diode array detector was used. The detection wavelengths were set as follows: 220 nm for paracetamol impurity K, 245 nm for paracetamol and its other impurities and 285 nm for codeine, pitophenone and their impurities. Impurities in valsartan, amlodipine besylate and hydrochlorothiazide were separated by reversed phase UHPLC method with gradient elution. Chromatographic column Zorbax Eclipse C8 RRHD, 100 x 3,0 mm, 1,8 µm heated to 30 řC and spectrophotometric detection were used. The detection wavelengths were set as..