There are two forms of primary packaging for solid pharmaceutical product:
  1. formable (thermoformable or cold-formable) materials
  2. flexible materials.
Formable materials (blisters and trays) can offer a water, oxygen, or UV barrier as well as a physical and mechanical barrier as a primary way to protect a drug and its delivery system against damage before administering.

Thermoformable materials are based on rigid polymer materials (PVC, PETG, APET, CPET, PP or COC) usually combined by coextrusion, coating, or lamination to barrier materials. Typical barrier materials include PCTFE (polychloro-trifluoroethylene, such as Honeywell's Aclar® fluoropolymer film), PVDC (polyvinylidene chloride), aluminum foil, or EVOH (ethylene vinyl alcohol) coextrusions (Honeywell's OxyShield®).

Transparency is often a desirable characteristic for such packages and is readily achieved by adhesive lamination of a rigid sheet to a transparent barrier web. Current blister packaging is mostly made from PVC or, when barrier is needed, from PVDC/PVC, PCTFE/PVC or foil-based structures.

Comparative WVTR (moisture vapor transmission rate)values of various blister films on flat sheet (38 deg C/90% RH - g/m2/day)

Materials of Construction / Type WVTR values (g/m2/day)
PVC / PVdC (250/40)0.75
PVC / PVdC (250/60)0.5
PVC/10μ PCTFE (Aclar) 0.45
COC 190 μ0.35
PVC/15μ PCTFE (Aclar) 0.36
PVC / PE / PVdC (250/25/90)0.31
PVC/20μ PCTFE (Aclar) 0.27
COC 240 μ0.28
COC 300 μ0.23
PVC/23μ PCTFE (Aclar) 0.23
COC 350 μ0.2
PVC/38μ PCTFE (Aclar) 0.15
PVC/51μ PCTFE (Aclar) 0.11
PVC/75μ PCTFE (Aclar) 0.08
PVC/102μ PCTFE (Aclar) 0.05
CFF (Alu/Alu) PVC/Alu45/OPA250

Flexible materials can offer barrier protection for the drug delivery system as well as flexibility in a number of different applications, such as pouches, bags, sachets; lidding (peelable or weld-sealed); or overwraps (secondary packaging). Transparency is highly desirable for flexible pharmaceutical packaging. It enhances product aesthetics, emphasizes product branding, and offers manufacturer and consumer alike a final quality control check before administration of the drug.