Moisture permeation of typical unit does repackaging materials

The moisture permeation of unit does repackaging materials used by various hospital and community pharmacies in a metropolitan area was studied. Commercial desiccant pellets were packaged in the same manner used for ordinary tablets and capsules. The samples were weighed and placed in a controlled chamber at about 75% relative humidity and 22 C, and tested for weight gain over a period of 4-10 days. Four types of packages were evaluated: (1) heat-sealed polyethylene bag, (2) polyvinyl chloride cups adhesive-sealed to multiple-ply paper, (3) heat-sealed "polycel-polyfoil" strip packages and (4) polyvinyl chloride/foil multiple-cup blister packs. A wide range of results was found. None of the containers tested was a good moisture barrier, although some offered protection for a limited time. Several needs were identified by this survey. Pharmacists need more information and an increased awareness concerning the permeation characteristics of repackaging materials, suitable operating procedures and the stability of pharmaceutical products. Standards must be established for repackaging materials as well as limits on storage periods for the repackaged pharmaceuticals. Procedures for pharmacists to test their own packaging systems, and a checklist of some important guidelines for repackaging in unit dose containers, are presented.