Dr. Hector Castro, a New York City physician was charged with running an interstate smuggling ring that trafficked $10 million worth of oxycodone across several states, including in Pennsylvania, where the investigation resulted in the largest prescription drug-related mass arrest in the state's history, authorities said Thursday, as reported by the Associated Press.

Authorities said that 49 people were arrested Tuesday, including the leaders of two major drug trafficking networks in Pennsylvania, after an undercover 15-month investigation had been conducted by the city's special narcotics unit.

"A scheme to obtain prescriptions in one state, and fill them and distribute them in another, exposes weakness in our regulatory systems," Special Narcotics Prosecutor Bridget Brennan said in a release.

Castro, who ran the Itzamna Medical Center in Manhattan, pleaded not guilty to 39 counts of criminal sale of a prescription for a controlled substance in Manhattan's state Supreme Court.  Over 500,000 pills were dispensed from New Jersey pharmacies based on more than 4,500 prescriptions that came from Castro's office, authorities said.

The investigation was launched after a case of a fatal oxycodone overdose in Middlesex, N.J., in 2011. Officials say a pill bottle with Castro's name was found on it.

Authorities said that Castro and his office manager, Patricia Valera, whose nickname was "Kardishian" illegally distributed pills in New York, New Jersey and Pennsylvania during the past two years.  Valera ran a separate scheme in which she stole prescription sheets from Castro, and forged them, authorities said. She later sold the sheets to two competing prescription drug trafficking rings in Pennsylvania, authorities said.

Valera, who lived in the Bronx, pleaded not guilty to charges including conspiracy and criminal sale of a prescription for a controlled substance. She was held in police custody until a bail hearing on April 11.

Castro, meanwhile was held on $500,000 bond and will appear in court on April 11. A locked box containing $20,000 in cash was among evidence seized from his home.