Viona Pharmaceuticals Inc., Issues Voluntary Nationwide Recall of Metformin HCl Extended-Release Tablets, USP 750 mg, Due to the Detection of N-Nitrosodimethylamine (NDMA) Impurity June 11, 2021 Auto Bot News 0 Viona Pharmaceuticals Inc., is voluntarily recalling 2 (two) lots of Metformin Hydrochloride Extended-Release Tablets, USP 750 mg to the retail level.