RESUMEN
One unknown impurity(Imp-II)during the analysis of laboratory batches of isoproterenol hydrochloride was detected in the level ranging from 0.04% to 0.12% by high performance liquid chromatography with UV detection. The unknown impurity structure was proposed as 4-[2-(propan-2-ylamino)ethyl]benzene-1,2-diol (Imp-Ⅱ)using the liquid chromatography–mass spectrophotometry(LC–MS)analysis.Imp-Ⅱ was isolated by semi-preparative liquid chromatography from the impurity-enriched reaction crude sample. Its proposed structure was confirmed by nuclear magnetic spectroscopy such as 1H, 13C,DEPT(1D NMR),HSQC(2D NMR) and infrared spectroscopy(IR),and retention time and purity with HPLC followed by the chemical synthesis. Due to less removable nature of Imp-II during the purification,the synthetic process was optimized proficiently to control the formation of Imp-II below to the limit<0.12% in the course of reaction.The new chemical route was developed for the preparation of this impurity in required quantity with purity to use as reference standard. The most probable mechanism for the formation of Imp-II was discussed in details.
RESUMEN
Objective:To study the effects and mechanisms of acetyl-11-keto-β-boswellic acid ( AKBA) in myocardial ischemic model induced by isoproterenol hydrochloride ( ISO) in rats. Methods:The SD rats were randomly divided into the sham group, model group, AKBA low dose group and AKBA high dose group. Myocardial injury model was induced by subcutaneous injection of ISO (100 mg·kg-1 ) . The change of ST segment in ECG was observed. Creatine kinase ( CK-MB) , cardiac troponin I ( cTnI) , lactate dehydro-genase( LDH) , malondialdehyde( MDA) and superoxide dismutase( SOD) in the blood were detected by ELISA. The change of histo-logical tissue was determined by HE staining, and cell apoptosis was analyzed by TUNEL assay. Results: Serum CK-MB, cTnI and LDH were decreased significantly in AKBA high dose group when compared with those in the model group. Compared with that in the model group, MDA content was lowered and the SOD activity was increased in AKBA high dose group. Furthermore, AKBA high dose group improved the pathologic changes of myocardium. TUNEL assay revealed significant reduction of cardiomyocytes apoptosis in the hearts of the ischemic rats in AKBA high dose group. Conclusion:AKBA has excellent cardioprotective effect on myocardial ischemic induced by ISO and protection of myocardial cells from injury.