Krka, dd, Smarjeska cesta 6, 8501 Novo mesto, Slovenia.
J Pharm Biomed Anal. 2010 Jun 5;52(2):294-9. doi: 10.1016/j.jpba.2009.12.018. Epub 2009 Dec 29.
Stress stability testing and forced degradation were used to determine the stability of enalapril maleate (EM) and to find a degradation pathway for the drug. The degradation impurities, formed under different stressed conditions, were investigated by HPLC and UPLC-MS methods. HPLC analysis showed several degradation impurities of which several were already determined, but on oxidation in the presence of magnesium monoperoxyphthalate (MMPP) several impurities of EM were observed which were not yet characterized. The HPLC methods for determination of EM were validated. The linearity of HPLC method was established in the concentration range between 0.5 and 10 microg/mL with correlation coefficient greater than 0.99. The LOD of EM was 0.2 microg/mL and LOQ was 0.5 microg/mL. The validated HPLC method was used to determine the degradation impurities in samples after stress stability testing and forced degradation of EM. In order to identify new degradation impurities of EM after forced degradation UPLC-MS/MS(n), Orbitrap has been used. It was found that new impurities are oxidation products: (S)-1-((S)-2-((S)-1-ethoxy-4-(o,m,p-hydroxyphenyl)-1-oxobutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid, (2S)-1-((2S)-2-((2S)-1-ethoxy-4-hydroxy-1-oxo-4-phenylbutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid. (S)-2-(3-phenylpropylamino)-1-(pyrrolidin-1-yl)propan-1-one was identified as a new degradation impurity.
马来酸依那普利的稳定性研究及其降解途径的确定
采用稳定性试验和强制降解试验的方法，研究马来酸依那普利（EM）的稳定性，寻找药物的降解途径。采用 HPLC 和 UPLC-MS 方法对不同应激条件下形成的降解杂质进行了研究。HPLC 分析表明，形成了几种降解杂质，其中一些已经确定，但在过氧单邻苯二甲酸镁（MMPP）存在下氧化时，观察到了几种尚未表征的 EM 降解杂质。建立了测定 EM 的 HPLC 方法。HPLC 方法的线性范围为 0.5-10μg/mL，相关系数大于 0.99。EM 的检测限为 0.2μg/mL，定量限为 0.5μg/mL。验证后的 HPLC 方法用于测定稳定性试验和强制降解后样品中的降解杂质。为了鉴定强制降解后 EM 的新降解杂质，采用 UPLC-MS/MS(n)，Orbitrap 进行鉴定。结果发现，新杂质是氧化产物：（S）-1-((S)-2-((S)-1-乙氧基-4-(邻、间、对羟基苯基）-1-氧代-2-丁基氨基）丙酰基）吡咯烷-2-羧酸，（2S）-1-((2S)-2-((2S)-1-乙氧基-4-羟基-1-氧代-4-苯基丁基氨基）丙酰基）吡咯烷-2-羧酸。（S）-2-(3-苯丙基氨基）-1-(吡咯烷-1-基）丙-1-酮被鉴定为新的降解杂质。
