A Columbia, Md., woman and a Miami couple have been charged with operating a major drug distribution network that transported large amounts of cocaine from Florida to Maryland under the guise of a shipping company, federal drug authorities said yesterday.

The arrests Thursday came after a federal grand jury in Baltimore handed up indictments of seven persons, three in the Columbia area and four in Miami.

Authorities alleged that large amounts of cocaine were hidden in tractor-trailers by concealing the drug in furniture shipments and transported from Miami to Columbia.

Bob O'Leary, a spokesman for the Drug Enforcement Administration, said the alleged drug ring had been using a phony shipping company out of an industrial building on Oakland Mills Road in Columbia as a cover.

O'Leary described the operation as "high level," dealing exclusively with large amounts of cocaine of high purity that apparently originated in the South American country of Colombia. O'Leary said it was unknown how much profits the alleged drug operation made.

"They only handled high-grade cocaine," O'Leary said. "This was not a street organization. These were people living the good and straight life who were actually drug pushers."

O'Leary added that the bogus shipping company in Columbia was the "focal point" for the operation and served as a local distribution outlet for the Washington area.

On Wednesday, police arrested Elena Renshaw of 5298 Eliots Oak Rd. in Columbia and Ramone Rodriguez, 33, and his wife Maria Rodriguez, 32, of Miami. O'Leary said the indictment charged them with conspiracy to distribute cocaine and various drug trafficking charges.

Two other persons, Gildardo Grisales and Benjamin Ginon, who were already in custody on unrelated charges, also were charged in the indictment.

Police are still seeking two other persons, one in Miami and another Columbia woman, who were named in the indictment, O'Leary said.

Howard County police and a DEA officer penetrated the alleged operation in 1984 by posing as drug dealers making cocaine purchases.

O'Leary said that during the investigation the undercover officers purchased about 6 1/2 pounds of the drug in Columbia and smaller amounts in Miami. He said the agents had tried to arrange a large purchase of about 80 pounds for about $20,000 a pound. The agents called off the deal when the drug dealers asked for the money in advance.

"We had negotiations with them for huge amounts, but they were asking for the cash up front, and we were not in a position to get that much in cash," O'Leary said.

He added that the investigation is continuing and additional arrests are expected.

"We are looking at this thing in both directions, where it came from outside the country and who it went to in Maryland," he said.