Separation and identification of degradation impurities of esomeprazole sodium.

Drug impurities are important factors that affect drug safety and efficacy. The aim of this study is to separate and confirm the structure of two degradation impurities of esomeprazole sodium, designated X and Y. The impurities X and Y were successfully isolated using preparative HPLC by developing separation methods with the help of ACD/Labs AutoChrom software. There was a steady increase in X and Y impurities in forced esomeprazole sodium degradation. Impurity X was confirmed as 6-methoxy-1h-benzo[d]imidazole-2-yl-4-amino-3,5-dimethylpyridinecarboxylate and impurity Y as 6-methoxy-1h-benzo[d]imidazole-2-yl-4-hydroxy-3,5-dimethylpyridinecarboxylate using nuclear magnetic resonance spectrometry, infrared spectroscopy, and high-resolution mass spectrometry. These findings provide a comprehensive understanding of the impurity profile of esomeprazole sodium because these impurities are reported for the first time. Based on our results, active pharmaceutical ingredient manufacturers can further control process parameters to reduce impurity generation, and drug production manufacturers can optimize the packaging and storage conditions of esomeprazole sodium.

LncRNA H19 induces immune dysregulation of BMMSCs, at least partly, by inhibiting IL-2 production.

BACKGROUND: Systemic lupus erythematosus (SLE) is a representative systemic autoimmune disease. LncRNA H19 has been identified to participate in various biological processes in human diseases. However, the role of H19 in SLE remains unclear. METHODS: In this study, we first examined H19 expression in SLE patients by RT-qPCR and found that H19 expression was significantly upregulated in the serum and bone marrow-derived mesenchymal stem cells (BMMSCs) of SLE patients and positively associated with SLE disease activity index. We then performed gain-of-function and loss-of-function using mimic-H19 (H19-OE) and inhibitor-H19 (H19-KD) to examine the effects of H19 on BMMSC differentiation, proliferation, migration, and apoptosis using flow cytometry, DAPI staining, and migration and apoptosis assays. RESULTS: The results showed that H19 inhibited proliferation and migration but promoted apoptosis of BMMSCs, interfered with BMMSCs-mediated Treg cell proliferation and differentiation, and regulated BMMSCs-mediated Tfh/Treg cell balance. Dual-luciferase reporter assay confirmed the in silico prediction of interaction between H19 and IL-2. Furthermore, RT-qPCR showed that H19 directly inhibited IL-2 transcription in BMMSCs. ELISA showed that both active and total IL-2 protein levels were significantly lower in SLE BMMSCs. More importantly, we found that IL-2 significantly enhanced H19-OE-induced Treg cell differentiation and migration of BMMSCs, and these effects were reversed by anti-IL-2 antibody. CONCLUSION: Overall, our study indicates that LncRNA H19 induces immune dysregulation of BMMSCs, at least partly, by inhibiting IL-2 production and might be a novel therapeutic target for SLE.

RNA HELICASE 32 is essential for female gametophyte development in Arabidopsis.

The normal progression of mitotic cycles and synchronized development within female reproductive organs are pivotal for sexual reproduction in plants. Nevertheless, our understanding of the genetic regulation governing mitotic cycles during the haploid phase of higher plants remains limited. In this study, we characterized RNA HELICASE 32 (RH32), which plays an essential role in female gametogenesis in Arabidopsis. The rh32 heterozygous mutant was semi-sterile, whereas the homozygous mutant was nonviable. The rh32 mutant allele could be transmitted through the male gametophyte, but not the female gametophyte. Phenotypic analysis revealed impaired mitotic progression, synchronization, and cell specification in rh32 female gametophytes, causing the arrest of embryo sacs. In the delayed pollination test, none of the retarded embryo sacs developed into functional female gametophytes, and the vast majority of rh32 female gametophytes were defective in the formation of the large central vacuole. RH32 is strongly expressed in the embryo sac. Knock-down of RH32 resulted in the accumulation of unprocessed 18 S pre-rRNA, implying that RH32 is involved in ribosome synthesis. Based on these findings, we propose that RH32 plays a role in ribosome synthesis, which is critical for multiple processes in female gametophyte development.

Tissue distribution study of mangiferin after intragastric administration of mangiferin monomer, Rhizoma Anemarrhenae, and Rhizoma Anemarrhenae-Phellodendron decoctions in normal or type 2 diabetic rats by LC-MS/MS.

A simple, accurate, and reliable liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated for the determination of mangiferin in rat plasma and tissue homogenates using rutin as an internal standard (IS). Chromatographic separation was achieved on a Shiseido CAPCELL PAK C18 column (150 × 2.0 mm, 5 µm) using a gradient elution of 1% acetic acid in water and methanol at a flow rate of 300 µL·min-1. Quantification was performed on an API 4000+ triple-quadrupole mass spectrometer equipped with a turbo electrospray ionization (ESI) source in positive ion multiple reaction monitoring (MRM) mode. Selected ion monitoring transitions of 423.1 → 273.1 and 611.4 → 303.3 were chosen to quantify mangiferin and IS. Biological samples were pretreated via protein precipitation with acetonitrile-acetic acid. The standard calibration curves were above the ranges of 2 to 500 ng·mL-1 and 5 to 2000 ng·mL-1 for tissues, and 1 to 600 ng·mL-1 for plasma. All calibration curves for tissue and plasma samples showed good linearity (r ≥ 0.9974) over the concentration ranges. Intra- and inter-day precisions were <14.0%, and accuracy ranged from 97.2% to 111.7%. The established method was successfully applied on mangiferin tissue distribution following the intragastric administration of mangiferin, Rhizoma Anemarrhenae (A. Rhizoma) decoction, or Rhizoma Anemarrhenae-Phellodendron (herb pair, HP) decoction under healthy or diabetic conditions. Mangiferin was detected from all the tested tissues (except for brain) after monomer administration, and the concentrations were lower compared with the decoction groups. Distributions in the HP group were lower than those in the A. Rhizoma group, but mangiferin content in pancreas was obviously higher than in other tissues and in the A. Rhizoma group. Compared with healthy rats, mangiferin distributions in pancreas and intestine were lower in diabetic rats administered with the same dose of the herb pair, but still higher than those in other tissues. In addition, distributions in liver, spleen, lung, kidney, stomach, and plasma were higher than those in the normal group.