Three death row inmates, including one who is set to be executed next week, have filed a federal lawsuit challenging the use of what they say are 'untested' drugs in the state's lethal injection process, 1200 WOAI news reports.


  Texas has been using the sedative pentobarbital to execute condemned criminals.  The state said last month it was running out of pentobarbital but announced without further clarification last week that it has obtained a new supply of the drug.


  "Of the drugs that we are aware that the TDCJ has on hand for executions, not a single one of them has ever before been used for purposes of execution," Maurie Levin, a law professor at UT Austin and a staunch death penalty opponent who is the attorney for the three inmates.


  "We are concerned that they are experimenting on people."


  The lawsuit claims that there is no evidence that the drugs will not cause pain and suffering, and violate the Eighth Amendment protections against cruel and unusual punishment.


  Texas has had repeated problems obtaining drugs to use in executions, largely because drug companies don't want their product associated with the death penalty.  The three drug 'cocktail' which was used for two decades to executed criminals in Texas had to be suspended in 2011 when shipment of the drug to Texas was barred by the drug's European manufacturer.