Investigators have identified a little-known drug recently intercepted at Philadelphia's airport, which is apparently an animal medicine used at raves.

The Web site Government Security News says the package of drugs was discovered by customs agents in Philadelphia in late February and it took weeks for determine what the unknown synthetic drug was.

A detailed analysis showed the package contained Methoxetamine, a new synthetic version of an animal tranquilizer called ketamine.

Katamine has been used for years as a recreational drug in the dance or rave culture, often with harmful effects. It is also known as Special K, Kit Kat or Cat Valium.

On March 14, the FDA confirmed that the white substance officers found in several plastic bags was the relatively new drug, seen only a few times previously in the U.S.

The Philadelphia package contained 63 grams in baggies, and it originated in the United Kingdom.

The drugs were intended for an address in Maine.

The street names for Methoxetamine are Ket, Kmax and Mexxy.

Customs officials said the interception in Philadelphia was only the sixth case nationally where the drug was found by investigators.

The drug first appeared in Europe in 2010 and soon made its way to the Internet.