Customs agents in Philadelphia nabbed six bottles containing more than a gallon of the opioid codeine, Customs and Border Protection announced Friday.

Codeine is a scheduled substance used recreationally in a drinkable mixture known on the street as “lean,” “sizzurp” and “purple drank.” Acquiring it legally in America requires a doctor’s prescription.

The shipment of six 17-ounce bottles, purportedly containing vegetable glycerine, arrived June 13 from the U.K. to an address in Philadelphia. Customs agents knew something was amiss when the bottles weighed more than they should have, as codeine is heavier than glycerine.

After agents took a couple days to determine the liquid inside the bottles was codeine syrup, the shipment was seized and handed over to Homeland Security Investigations agents working at Philadelphia International Airport.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.