A federal appeals court on Friday upheld the dismissal of nearly all claims in 68 cases seeking to hold drug makers liable for injuries from the use of the prescription painkillers Darvon and Darvocet, which were pulled from the U.S. market in 2010. The plaintiffs, who used generic versions of the drugs, had invoked design defect laws in 22 U.S. states in claiming that generic drug makers misbranded the drugs. Many also sought to hold brand-name drug makers liable for alleged misrepresentations made to prescribing doctors.