All of the following drugs are used for cervical ripening during pregnancy, EXCEPT:

Cervical ripening refers to a series of events taking place in the cervix during labour. Ripe cervix is shoened, softened, paly dilated and central in position. Pharmacologic drugs used for ripening of cervix are prostaglandin E2, misoprostol (PGE1), oxytocin and mifepristone. Progesterone is not indicated in ripening of cervix. Ref: Maternity, Newborn, and Women's Health Nursing: Comprehensive Care Across the Lifespan By Susan A. Orshan, Page 653