(This chapter will become official on May 1, 2020. Early adoption of the requirements in this chapter and its companion chapter Plastic Packaging Systems for Pharmaceutical Use 〈661.2〉 are permitted by USP. When early adoption is not used, Plastic Packaging Systems and Their Materials of Construction 〈661〉 will apply and must be met wherever this chapter or 〈661.2〉 is referenced in the USP–NF.)