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USP Issues Minimum Standards for Unit Dose Repackaging

Cheryl A. Thompson

The material to be used in repackaging a tablet or capsule into a blister package should be selected on the basis of the degree of moisture protection required and how the package will be used, according to a new chapter for pharmacies and commercial repackaging firms in the nation's official pharmacopeia.1 Released in February as part of the first supplement to The United States Pharmacopeia, 25th Revision, and The National Formulary, 20th Edition, and effective since April, the informational chapter, while authoritative, does not by itself carry legal force or replace the requirements of any regulatory agency.

For drug products whose labeled storage condition includes protection from moisture, practitioners and repackagers must use a blister film that provides high or extreme moisture protection. According to the new chapter, polyvinyl chloride (PVC) provides a nominal to zero moisture barrier, whereas laminations of PVC with polychlorotrifluoroethylene (PCTFE) provide medium to extreme protection against moisture penetration; laminations of PVC with polyvinylidene chloride (PVdC), medium to high protection; and cold form foil, extreme protection. The amount of moisture protection provided by a lamination blister depends on the gauge of the PCTFE film or the coating weight of the PVdC layer. Materials in a blister film should be judged on their performance as a formed container (the blister), not a flat sheet.

A requirement issued two years ago by the United States Pharmacopeia stated that the plastic material in unit dose packages must provide better protection against moisture permeation than PVC but did not specify how much better.

Sealed to the blister film is the lid stock, which is typically aluminum and available as a multiple-layer peelable foil or a push-through foil.

The beyond-use date for a drug product repackaged in a unit dose container, according to the chapter, is the shorter of one year or the time remaining of the manufacturer's expiration date. If data are available on the stability of the drug product in the new packaging, then that information should be used in establishing the beyond-use date so long as it does not exceed the manufacturer's expiration date.

A standard inspection plan should be used to verify the adequacy of the repackaging operation. For example, someone should test the integrity of the package's seal.

The chapter briefly discusses strip packs as unit dose containers and describes the minimum requirements, such as the facility, for repackaging medications.

  1. Packaging practice—repackaging a single solid oral drug product into a unit-dose container. Supplement 1 to The United States pharmacopeia, 25th rev., and The national formulary, 20th ed. Rockville, MD: The United States Pharmacopeial Convention; 2002:2791-5.