Desenvolvimento e validação de um método indicativo de estabilidade por LC-UV-CAD para análise de cloridrato de trazodona

Abstract

Depression is defined by the World Health Organization (WHO) as a mental disorder and can manifest in different ways according to each individual, treatment is performed with antidepressants. Among the antidepressants used, there is Trazodone Hydrochloride. Trazodone is described in the american and british pharmacopoeia, but the methods available in pharmacopoeia used UV detection for drug quantification and are not capable of quantifying the formation of possible degradation products or impurities, such as compounds with low molar absorptivity, which do not present chromophore groups in their chemical structures and do not have certified standards available. Thus, the development and validation of analytical methodology indicative of stability by liquid chromatography coupled to the UV detector and also to the Corona® CAD® detector (LC-CAD) is important. During the development of the method the chromatographic conditions were optimized and defined using the C18 column (100 mm x 2.1 x 2.2 μm); mobile phase composed of 20 mM ammonium acetate + 0.1% triethylamine; pH 6.0 and methanol (40:60); flow 0.3 mL min-1; wavelength of 255 nm and column temperature of 35°C. The proposed analytical method was validated according to ANVISA Resolution 166/2017. The present work evaluated the intrinsic stability of the drug through the studies of forced degradation. Trazodone presented degradation when submitted to basic hydrolysis and oxidative solution and remained stable in conditions of heat, humidity, light and acid hydrolysis. The products found were identified by LC-MS and had their chemical structures determined. The method presented a linear range of 10 to 250 μg mL-1; LD (detection limit) = 2 μg mL-1 and LQ (quantification limit) = 6 μg mL-1 for the UV detector; LD = 0.3 μg mL-1 and LQ = 0.9 μg mL-1 for the CAD detector. Precision was evaluated at three concentration levels (10, 100 and 250 μg mL-1) and expressed in terms of repeatability and intermediate precision. The values found for both detectors of coefficient of variation (C.V.) ranged from 0.18 to 0.95%. Accuracy was assessed by analyte recovery assays and values ranged from 97 to 101%. The method was considered robust by the Youden test for the UV and CAD detectors and the analyzed parameters did not present significant influence in the developed method.