Disclosed herein are materials, articles of manufacture, and methods for reducing, mitigating, or precluding formation of and/or amount of a nitrosating agent and/or an N-nitroso compound, including an N-nitrosamine, from a packaging containing an active agent and a pharmaceutical dosage form in an enclosure, wherein the active agent is effective to reduce mitigate or preclude the formation and/or amount of a nitrosating agent and/or N-nitroso compound in the enclosure and/or in the pharmaceutical dosage form. Provided are drug delivery systems comprising a blister pack configured to house multiple pharmaceutical dosage forms, the blister pack comprising an active ingredient that is effective to reduce, mitigate or preclude the formation and/or amount of a nitrosating agent and/or N-nitroso compound in an enclosure of the blister pack and/or in the pharmaceutical dosage form.