Avoiding N-nitrosodimethylamine formation in metformin pharmaceuticals by limiting dimethylamine and nitrite.

Since late 2019, concerns regarding trace levels of the probable human carcinogen N-dimethylnitrosamine (NDMA) in Metformin-containing pharmaceuticals have been an issue if they exceeded the maximum allowable intake of 96 ng/day for a medicine with long-term intake. Here, we report results from an extensive analysis of NDMA content along the active pharmaceutical ingredient (API) manufacturing process as well as two different drug product manufacturing processes. Our findings confirm that Metformin API is not a significant source of NDMA found in Metformin pharmaceuticals and that NDMA is created at those steps of the drug product manufacturing that introduce heat and nitrite. We demonstrate that reduction of nitrite from excipients is an effective means to reduce NDMA in the drug product. Limiting residual dimethylamine in the API has proven to be another important factor for NDMA control as dimethylamine leads to formation of NDMA in the drug products. Furthermore, analysis of historical batches of drug products has shown that NDMA may increase during storage, but the levels reached were not shelf-life limiting for the products under study.

Synthesis of Cis-fused pyran indolocarbazole derivatives that inhibit FLT3 kinase and the DNA damage kinase, checkpoint kinase 1.

Protein kinases are important enzymes in solid tumour and leukaemia pathologies. Their structures are well understood at the atomic level and their key role in the progression of certain cancers makes them valuable targets for anti-cancer therapy. Through medicinal chemical approaches, we developed an efficient preparative stereospecific synthesis of N12, N13 pyran-bridged indolocarbazoles that opens access to functional diversity within this previously challenging series. We focused upon the indolocarbazole class of chemical inhibitors, which includes S27888, an inhibitor we previously identified. We used biochemical and cell-based assays to identify small molecule inhibitors of Checkpoint kinase 1 (Chk1), a serine/threonine protein kinase that is activated when cancer cells are treated with genotoxic agents. These compounds show a promising inhibitory profile on Chk1. Furthermore, these compounds are active against FLT3, which is a tyrosine kinase that is frequently activated in human leukaemias. These data suggest that this chemical class may provide a source of therapeutic compounds for a broad range of human cancers.