Pharmaceutical compositions containing indistinguishable drug components

A method of preparing a pharmaceutical multi-particulate dosage form comprising a first population of particles comprising an opioid agonist and a second population of particles comprising an opioid antagonist, wherein said method comprises the steps of:

• (a) preparing opioid agonist cores by layering an aqueous solution comprising said opioid agonist and a binder on non-pareil seeds;
• (b) applying a sustained release coating on said opioid agonist cores, said sustained release coating comprising a water insoluble polymer or a combination of a water insoluble polymer and a water soluble polymer to produce a first population of particles comprising said opioid agonist;
• (c) preparing opioid antagonist cores by layering an aqueous solution comprising said opioid antagonist and a binder on non-pareil seeds;
• (d) applying a sustained release coating on said opioid antagonist cores, said sustained release coating comprising a water insoluble polymer or a combination of a water insoluble polymer and a water soluble polymer to produce a second population of particles comprising said opioid antagonist;
• and
• (e) filling capsules with said first population of particles and said second population of particles wherein said opioid agonist particles provide an analgesically effective amount of opioid agonist and said opioid antagonist particles provide an amount of opioid antagonist effective to attenuate side effects associated with chronic dosing of said opioid agonists, said first population of particles and said second population of particles being visually indistinguishable, thereby reducing the potential for drug abuse of said opioid agonist by separation of said opioid agonist from said opioid antagonist.