AstraZeneca has agreed to pay a $520m fine to settle allegations that it illegally marketed its schizophrenia drug Seroquel for unapproved uses.The drug giant denies the charges, but will pay the penalty, agreed in principle last October and taken as a reserve in 2009. It has also entered into a corporate integrity agreement with the Office of Inspector General of the United States Department of Health and Human Services, which will be in effect for five years.The government accused Astra of marketing Seroquel for unapproved diseases like Alzheimer's and anxiety to doctors, who then prescribing it to patients.