NEW YORK -- A major New York hospital's former pharmacy chief stole nearly 200,000 oxycodone pills from the medical centre over more than five years and has been charged under a state drug-kingpin law more often aimed at accused street dealers, narcotics prosecutors said Tuesday.

Anthony D'Alessandro pleaded not guilty. His lawyer, Joseph Sorrentino, said D'Alessandro is no drug lord, but rather a man who told a hospital investigator he'd had a drug problem.

City Special Narcotics Prosecutor Bridget Brennan's office is still investigating what became of the drugs but believes they ended up on the thriving black market for prescription painkillers, where the more than 193,000 missing pills could get a total of about $5.6 million.

While serving as Mount Sinai Beth Israel's pharmacy director for 14 years before his firing this year, D'Alessando is accused of exploiting his access to the hospital's drug vault to grab oxycodone pills on nearly 220 different dates: about 100 at a time when he started in January 2009, but 1,500 at a time when the scheme came to light this spring, Brennan's office said.

Hospital officials first approached him April 1 about the disappearing drugs, and he signed out another 1,500 pills the next day, prosecutors said.

The hospital launched the investigation in response to an anonymous letter, which came after D'Alessandro's longtime employer, Beth Israel Medical Center, merged into the Mount Sinai Health System in September.

The hospital noted in a statement that it brought the case to authorities and fired D'Alessandro.

D'Alessandro, 47, was facing charges including a major drug trafficking offence that carries the potential for life in prison. It's the first time Brennan's office, which focuses on drug cases citywide, has deployed the 2009 law against a pharmacist.

Around the country, at least a few other hospital pharmacists have been accused of stealing drugs they were supposed to dispense.