以光學活性高效液相屬析儀分析血液中ML-1035對掌異構物   全文下載

Determination of ML-1035 Enantiomers in Plasma by Chiral High Performance Liquid Chromatography

ML-1035為類似於mefoclopromide，作用於胃腸道之消化劑，其結構中具有不對稱中心，本文敘述使用光學活性高效液相層析法分析其R及S對掌異構物之方法。血液樣本在鹼性條件下以二氯乙烷粹取，粹取液抽乾後溶於層析分離使用之移動相。層析使用Chiralcel OD管柱，以含1% TEA 之正甲烷 ： 絕對酒精= 1 ： 1 （V／V） 為移動相，層析物以螢光偵測器（激發波長310mm，發射波長350mm）偵測之。此分析方法對ML-1035對掌異構物在25至2500ng／ml濃度範圍內具有線性關係，其相關係數大於0.9987，不同次分析間之精確度在± 9.5%之間，準確度則介於理論值之93.9%至103.4%之間。實驗狗以口服或靜脈注射ML-1035後，以此方法可得到良好的分析效果，此方法並用於試驗偵測R及S對掌異構物之轉位反應。資料顯示該對掌異構物無論在體內或體外試驗中均無因代謝而產生明顯之轉位反應。

ML-1035, is a gastroprokinetic agent structurally related to metoclopramide. Because ML- 1035 contains an asymmetric chiral sulfoxide moiety, a chiral HPLC method was developed to separate and quantitate its R and S enantiomers in plasma. The ML-1035 enantiomers present in plasma were extracted with dichloroethane under alkaline conditions. The extract was evaporated to dryness and reconstituted in the mobile phase. The samples were chromatographed on a Chiralcel OD HPLC column with hexane: absolute ethanol (1% TEA) with a ratio of 1: 1 (v/v) as the mobile phase. The enantiomers of the unchanged drug were quantified by fluorescence detection (ex: 310 nm, em: 350 nm). The method provided a linear response for both enantiomers over a concentration range of 25 (limit of quantitation) to 2500 ng/ml with correlation coefficients of 0.9987 or greater. The interassay precision was 9.5% or less and the accuracy ranged form 93.9% to 103.4% of the theoretical value. This method was utilized in determining the plasma concentrations of the Rand S enantiomers following oral and intravenous administration of R or S enantiomers to dogs. The method was also adapted to measure enantiomer levels from in vitro reaction mixtures so that the possibility of metabolic inversion could be assessed. The data suggest that no significant level of inversion between the enantiomers occurred either in vivo or in vitro.