A doctor who pleaded guilty to selling ketamine to Matthew Perry in the weeks before the "Friends" star's overdose death was sentenced to 2 1/2 years in prison on Wednesday. Judge Sherilyn Peace Garnett handed down the sentence plus two years of probation to 44-year-old Dr. Salvador Plasencia in a federal courtroom in Los Angeles.The judge emphasized that Plasencia didn't provide the ketamine that killed Perry, but told him, "You and others helped Mr. Perry on the road to such an ending by continuing to feed his ketamine addiction.""You exploited Mr.