A federal grand jury has indicted five men on conspiracy charges in connection with an alleged East Coast drug ring centered in the Washington and Philadelphia areas.

The 13-count indictment, returned Tuesday and made public yesterday in Alexandria, charged that the ring obtained cocaine and methaqualone, a tranquilizer, in the Miami area for sale here and in Philadelphia between November 1979 and last month.

A spokesman for the U.S. Drug Enforcement Administration said the agency's investigation showed the alleged ring was capable of selling from 15,000 to 20,000 methaqualone pills a month. The street price of methaqualone is $2 to $5 per pill, the spokesman said.

Two defendants, Allen Bisch of Arlington and Alan Einseln of Annandale (also known as "Big Al"), were arrested at their homes Wednesday. A third man, Leonard Wolf, also was arrested Wednesday in a Philadelphia suburb.

The alleged ringleader, Alan Jay Chernick, was taken into custody Dec. 30 in the Distict by DEA agents who seized 5,000 methaqualone pills during the arrest, the spokesman said. The fifth man, Fred Harry Abrams of Philadelphia, was still at large late yesterday.

Also named were two unindicted co-conspirators, identified as Frederick M. Hale and Maria Valiant.