Mirtazapine Related Compound D (50 mg) (2-Methyl-1,2,3,4-tetrahydrobenzo[c]pyrazino[1,2-a]pyrido[3,2-f]azepin-10(14bH)-one);1,3,4,14b-Tetrahydro-2-Methyl-;Mirtazapine EP IMpurity F;Mirtazapine IMpurity F (10-oxo Mirtazapine);Mirtazapine Related CoMpound D;10-Oxo Mirtazapine;10-Oxo Mirtazapine (Mirtazapine Impurity F);2-methyl-1,3,4,14b-tetrahydrobenzo[c]pyrazino[1,2-a]pyrido[3,2-f]azepin-10(2H)-one