Pioglitazone EP Impurity - C

5-{4-[2-(5-Ethyl-pyridin-2-yl)-ethoxy]-benzylidene}-3-[2-(5-ethyl-pyridin-2-yl)-ethyl]-thiazolidine-2,4-dione; N-Alkyl Pioglitazone; 5-[[4-[2-(5-Ethyl-2-pyridinyl)ethoxy]phenyl]methyl]-3-[2-(5-ethyl-2-pyridinyl)ethyl]-2,4-thiazolidinedione;N-Alkylpioglitazone, (±)-5-{4-[2-(5-Ethylpyridin-2-yl)ethoxy]benzyl}-3-[2-(5-ethylpyridin-2-yl)ethyl]thiazolidine-2,4-dione, Pioglitazone Related Compound C (USP);