Rigid PVC refers to the lack of softening ingredients and plasticizers in PVC-forming film. Without plasticizers, PVC blisters provide structural stiffness & physical defense for the dosage form. The blister cavity must stay accessible to maintain the push-through effect, and the generated web must not be too difficult to collapse when pressed. As a result, depending on the size and shape of the cavity, a PVC sheet thickness of 200 to 300 is the most common.
PVC Foil Or PVDC Foil For Medicinal Purposes?
Flexible PVC foil in pharma is a transparent, strong, and low WVTR material. In addition to its outstanding thermoformability, flexural strength, and chemical resistance, this material has poor resistance to oils, fats, or flavoring components, is stable, and is inexpensive. Rigid PVC is the best material for blister packaging because of these qualities, and it holds a monopoly on the plastic component market. The thickness of thermoformed PVC films is around 10 mil. PVC seems to have a harmful ecological connotation due to its chlorine content and highly toxic dioxins. The key drawbacks are the poor hindrance against moisture ingress and oxygen ingress.
Pharmaceutical blisters commonly use PVC sheets with 250 or 0.250 mm thickness. Water Vapor Transmission Rates (WVTR) and Oxygen Transmission Rate (OTR) of a 250 PVC film are typically around 3.0 g/m2/day at 38°C/90% RH and roughly 20 cc/m2/day, respectively. PVC film can be covered using PVDC or bonded to PCTFE and COC to offset its lack of barrier qualities. For medicinal blister packaging, PVC-based multi-layer blister films are commonly utilized, with the PVC serving as the diagnostic spine of the structure. Pigments and UV filters can be used to colour the PVC layer.
Plastic coated in PVDC foil (Polyvinylidene Chloride). Blister packaging relies heavily on PVDC laminations and coatings on PVC. Reduced permeability for PVC blister packages to gas and moisture can be achieved by using PVDC. The PVDC coat is 1–2 mil thick, while coated PVC films are 8–10 mil thick. On one side, the products and the lidding material are normally in contact with the coating.
Choices and considerations in terms of materials
Plastics and polymers, including HDPE, LDPE, PET, PVC, and PP, are the most common materials used in pharmaceutical packaging. It is possible to make vials, bottles, syringes, and blisters with plastic at a low cost and ease. It may be laminated with metals like aluminum to create flexible packaging.
A product’s demand for light, heat, and moisture protection dictates the type of packaging material used. A drug’s shelf life & storage circumstances will be affected by the material’s resistance to all of these factors. A drug’s stability studies are typically conducted during development to determine which materials are the most appropriate in light of the various costs involved.
Blister packaging inside the pharmaceutical industry is critical.
Packaging is a critical component of such drug delivery and a critical marketing tool. Pharma firms increasingly rely on their packaging to safeguard and sell their medicines as markets expand, customer needs develop, and regulatory requirements change. The blister pack shape has several advantages that are in line with the needs of the pharma industry today. Consequently, blister packages have become and will continue to be the most popular and fastest-growing labelling options for the pharmaceutical industry.
Blister packing types
PVC, PCTFE, PVDC, and thermoform blisters, for less sensitive drugs, or Aluminum foil for blister packaging, for more sensitive Active Pharmaceutical Ingredients (APIs), are only a few of the options available in blister packaging.
- There are now two main forms of blister packing used in the pharmaceutical industry. Among them:
- To create the cavity, a thermoformed plastic is used, while the lid is made of plastic or mixing of multiple materials.
- Cold stretching is used to form the cavity in the second type, which includes foil as a key component of both the webs and the webs themselves.
Comparison of thermal and cold-forming
Most of the market’s growth comes from thermoformed blister packs, which have the largest share. PVC, PVDC (covered PVC), PP, PET, ACLAR, and COCs are the most often used plastic forming films (cyclo-olefin copolymers).
Another way to make a blister package is cold forming an aluminum-based sheet into the desired shape (OPA-ALU-PVC). Alu Alu blister’s packability allows for practically total water vapor permeability, making it a more difficult and expensive process than thermoforming for items that are particularly sensitive to moisture. Blisters made of aluminium cost far more than those made of PVC, and this isn’t only due to the higher cost of aluminum as a raw material. The laminate foil’s lower formability results in larger cavities than necessary for the product, which raises the cost per pack. There will be an increase in secondary packaging and transport expenses due to this.
However, the pharmaceutical sector is stepping up its use of packaging as just a marketing technique due to the prevalence of generic OTC medications and a more competitive market. There is also a demand for designs that promote patient compliance, deal with child resistance, or prevent counterfeiting in some way or another.