President Resigns From Medstone International : Technology: The firm has failed to win federal approval of its equipment to remove gallstones.

A month after suspending efforts to win federal approval for equipment to remove gallstones, Medstone International Inc. announced Thursday that its president and chief operating officer has resigned.

Richard Ferrari, who joined the company in April, resigned to pursue other interests, the company said. His resignation comes less than seven weeks after the company’s founder and chairman, Freeman Rose, left the company in November.

Rose formed Medstone in October, 1984, to produce and market equipment known as lithotripters, sophisticated shock-wave devices used to shatter kidney stones and gallstones without surgery.

In November, the company announced it had given up on efforts to obtain Food and Drug Administration approval to use its lithotripters for gallstone procedures. The scientific community had raised questions about the effectiveness of the machines for that purpose.

“The recent suspension of the gallstone lithotripsy program reduced the scope of Medstone’s shock-wave-therapy business, and prompted me to pursue other personal growth opportunities,” Ferrari said in a prepared statement.

Ferrari, a former executive vice president of ADAC Laboratories in Milpitas, replaced acting president Jack Olshansky in April as president and chief operating officer. He assumed the duties of chief executive after Rose gave up the title in July. Ferrari could not be reached for comment.

David V. Radlinski, executive vice president and chief financial officer of the company, said Ferrari will be replaced internally in January from among members of the executive staff.

Despite the recent setbacks, Radlinski said the company would continue to market its technology for use in destroying kidney stones and attempt to shift away from its dependence on medical capital equipment markets toward the larger health-care business.

“We have $10 million and opportunities in different technologies,” Radlinski said. “No decisions have been made about future investments.”

The company’s stock closed Thursday at $1.25, down 12.5 cents in over-the-counter trading.

For the third quarter ended Sept. 30, the company reported a loss of $2.3 million on revenue of $1.7 million, compared with a loss of $1.6 million on revenue of $1.2 million. The loss reflected heavy competition for the company’s products, Radlinski said.