Blister & strip packaging

Blister & Strip Packaging
Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management,
SVKM’S NMIMS, Mumbai
Dr. Anil M. Pethe

Blister Pack Introduction
 Blister pack is a term for several types of
pre-formed plastic packaging used for
small consumer goods.
 The two primary components of a blister
pack are the cavity or pocket made from a
 "formable" web, either plastic or aluminum
 the lidding, made from paper, paperboard,
plastic or aluminum.
 The "formed" cavity or pocket contains
the product and the "lidding" seals the
product in the package.

Blister Pack Introduction (Cont.)
 Blister packs are commonly used as unit-dose packaging for
pharmaceutical tablets, capsules or lozenges.
 Blister packs can provide barrier protection for shelf life
requirements, and a degree of tamper resistance.
 In the USA, blister packs are mainly used for packing physician
samples of drug products, or for Over The Counter (OTC)
products in the pharmacy.
 In other parts of the world, blister packs are the main packaging
type since pharmacy dispensing and re-packaging are not
common.
 A series of blister cavities is sometimes called a blister card or
blister strip as well as blister pack. In some parts of the world the
blister pack is known as a Push-Through-Pack (PTP).

Blister Pack Introduction (Cont.)
 The main advantages of unit-dose blister packs over other
methods of packing pharmaceutical products are the
assurance of product/packaging integrity (including shelf life)
of each individual dose
 The possibility to create a compliance pack or calendar pack
by printing the days of the week above each dose.
 Blister packs also hinder the use of OTC drugs in the
manufacture of illegal drugs.

Consumer goods Blister Packs
 Other types of blister packs consist of carded packaging where
goods such as toys, hardware, and electrical items are contained
between a specially made paperboard card and clear pre-formed
plastic such as PVC.
 The consumer can easily examine the product through the
transparent plastic.
 The adhesive is strong enough so that the pack may hang on a peg,
but weak enough so that the package can be easily opened.

Consumer goods Blister Packs (Cont.)
 Sometimes, with large items, the card has a
perforated window for access.
 A more secure package is known as a
clamshell.
 It is often used to deter package pilferage for
small high-value items, such as consumer
electronics.
 It consists of either two pre-formed plastic
sheets or one sheet folded over onto itself and
fused at the edges. They are usually designed
to be difficult to open by hand so as to deter
tampering.
 A pair of scissors or a sharp knife is often
required to open them (although often
coming in the same package).

 They provide barrier protection for shelf life requirements.
 They also provide a degree of tamper resistance.
 The most important reason for introducing blister
packaging technology was to offer patients a clearly marked
individual dose, enabling them to check whether they had
taken the prescribed drugs on a given day.
 Moreover, the drugs that were not taken remained in the
original package and were fully protected against adverse
external conditions.
 The patient could handle the blister package more easily
and could store it more conveniently than conventional
packages.
 Protection from Moisture, Gas, Light & Temperature
 Compliance – Regulatory & Patient
Uses of Blister Packaging

Advantages of blister packaging
 Reduced costs and higher packaging speeds relative to
other packaging materials.
 Blister packaging helps retain product integrity because
drugs that are prepackaged in blisters are shielded from
adverse conditions.
 Furthermore, opportunities for product contamination are
minimal.
 and each dose is identified by product name, lot number,
and expiration date.

Advantages of blister packaging (cont.)
 Blister packaging protects pharmaceuticals in the home
better than bottles do.
 Tamper evidence is another strength of blister packaging.
The dosage units are individually sealed in constructions of
plastic, foil, and/or paper. With blister packaging, however,
each tablet or capsule is individually protected from
tampering until use, so any form of tampering with a
blister package is immediately visible.

Basic configuration of blister packaging
Two basic types of pharmaceutical blister packages exist;
1. In one variety the cavity is constructed of clear, thermoformed
plastic, and the lid is formed of clear plastic or a combination of
plastic, paper, and/or foil.
2. The other type of package contains foil as an essential
component of both webs, and its cavity is created by cold
stretching.

Production of Blisters
There are 3 different methods for production of blisters
Thermoforming
Cold forming
Thermo-cold complex blistering

Thermoforming
 In the case of thermoforming, a plastic film or sheet is unwound
from the reel and guided though a pre-heating station on the
blister line.
 The temperature of the pre-heating plates (upper and lower
plates) is such that the plastic will soften and become pliable.
 The warm plastic will then arrive in a forming station where a large
pressure (4 to 8 bar) will form the blister cavity into a negative
mold.
 The mold is cooled such that the plastic becomes rigid again and
maintains its shape when removed from the mold.
 In case of difficult shapes, the warm film will be physically pushed
down partially into the cavity by a "plug-assist" feature.
 Plug-assist results in a blister cavity with more uniform wall
distribution and is typically used when the cavity size and shape is
larger than a small tablet.

Cold forming
 In the case of cold forming, an aluminum-based laminate film is
simply pressed into a mold by means of a stamp.
 The aluminum will be elongated and maintain the formed shape.
 In the industry these blisters are called cold form foil (CFF)
blisters.
Advantage of cold form foil blisters is
 Use of aluminum offers a near complete barrier for water and
oxygen, allowing an extended product expiry date.
Disadvantages of cold form foil blisters are:
 The slower speed of production compared to thermoforming
 The lack of transparency of the package
 The larger size of the blister card (aluminum can not be formed
with near 90 degree angles).

Components of blisters
The four basic components of pharmaceutical blister
packages are;
1. The forming film (Forming films account for approximately
80–85% of the blister package)
2. The lidding material (lidding materials make up 15–20% of
the total weight of the package.)
3. Heat seal coating
4. Printing ink

1. Forming Film
 The forming film is the packaging component that
receives the product in deep drawn pockets.
 One key to package success is selecting the right
plastic film for the blisters in terms of its;
 Property type,
 Grade,
 Thickness.

Selection of forming film
Consideration must be given to the;
 Height and weight of the product,
 Sharp or pointed edges of the final package,
 The impact resistance,
 Aging, migration, and cost of the film.
 The plastic also must be compatible with the product.
 Factors influencing package production and speed of
assembly must be taken into account, including heat sealing
properties and the ease of cutting and trimming formed
blisters.

Types of forming film
 Thermoforming film
 PVC (Poly vinyl chloride)
 PCTFE (PVC/Polychlorotrifluoroethylene)
 PVDC (Polyvinylidene chloride)
 PS (Polystyrene )
 Cyclic olefin copolymers (COC)
 Cold forming film
 Aluminum foil

Polyvinyl Chloride (PVC)
 The most basic material for the forming web is PVC or Polyvinyl
Chloride.
 The principal advantages of PVC are the low cost and the ease of
thermoforming.
 The main disadvantages are the poor barrier against moisture
ingress and oxygen ingress; moreover PVC has a negative
environmental connotation due to its chlorine content.
 In the case of blister packaging the PVC sheet does not contain
any plasticizer and is sometimes referred to as Rigid PVC or RPVC.
 In the absence of plasticizers, PVC blisters offer structural rigidity
and physical protection for the pharmaceutical dosage form.
 On the other hand, the blister cavity must remain accessible by
the push-through effect and the formed web may not be too hard
to collapse when pressed upon;

Polyvinyl Chloride (PVC)
 For this reason the PVC sheet thickness is typically chosen
between 200µ to 300µ depending on the cavity size and shape.
 Most PVC sheets for pharmaceutical blisters are 250µ or
0.250 mm in thickness.
 Typical values for the WVTR or MVTR of a 250µ PVC film are
around 3.0 g/m2
/day measured at 38°C/90%RH
 The Oxygen Transmission Rate (OTR) is around 20 cc/m2
/day.
 In order to overcome the lack of barrier properties of PVC film, it
can be coated with PVDC or laminated to PCTFE or COC to
increase the protective properties.
 Multi-layer blister films based on PVC are often used for
pharmaceutical blister packaging, whereby the PVC serves as the
thermo formable backbone of the structure.
 Also, the PVC layer can be colored with pigments and/or UV
filters.

Barrier Packaging foils
 Low barrier film – PVC
 Medium barrier film – PVDC
 High barrier film – ACLAR (PCTFE) & ALU/ALU

Poly-chloro-tri-fluroethylene (PCTFE)
 Polychlorotrifluoro ethylene or PCTFE can be laminated to PVC
to obtain very high moisture barrier.
 Typical constructions used for pharmaceutical products are 250µ
PVC film laminated to 15µ-100µ PCTFE film.
 Duplex structures are PVC/PCTFE
 Triplex laminates are PVC/PE/PCTFE.
 Deeper cavities can be formed by using the triplex structures
with PE. Typical WVTR values are between 0.06 - 0.40 g/m2/day.

Polyvinylidene Chloride (PVDC)
 PVC/PVdC laminations
 PVC is coated with an emulsion of PVdC (Polyvinylidene Chloride)
 The coating weights of PVdC commonly used are 40, 60, 90, g per
m², and the film is offered with or without a middle layer of
polyethylene.
 The polyethylene is used with heavier coating weights such as 60
and 90 g per m², to improve the thermoforming characteristics of
the blister cavity.

Cyclic olefin copolymers (COC)
 Cyclic olefin copolymers (COC) or polymers (COP) can provide
moisture barrier to blister packs, typically in multilayered
combinations with polypropylene (PP), polyethylene (PE), or glycol-
modified polyethylene terephthalate (PETg).
 Cyclic olefin resins are generally amorphous and are noted for good
thermoforming characteristics even in deep cavities, leading some
to use COC in blister packaging as a thermoforming enhancer,
particularly in combination with PP or PE.
 Films can be manufactured via coextrusion or lamination.
 WVTR values of commercial cyclic olefin-based pharmaceutical
blister films typically range from 0.20 to 0.35 g/m2/day at 38C/90%
RH.
 Unlike PVC and other common pharmaceutical barrier resins, cyclic
olefin resins do not contain chlorine or other halogens in their
molecular structure, being comprised solely of carbon and
hydrogen.

Cold form foil
 is used for products that are extremely hygroscopic or
light sensitive.
 It is an extreme moisture barrier and consists of three
layer: PVC, aluminium foil and nylon.

Comparison of forming film
mil- a unit of length equal to 1
⁄1000 inch used especially in measuring thickness (as of plastic films)

2. Lidding Material
The lidding material provides the base or main structural
component upon which the final blister package is built.
It must be selected according to;
The size,
Shape,
Weight of the product
As well as the style of the package to be produced

Consideration in selection of lidding material
 The surface of the lidding material must be compatible with the
heat-seal coating process.
 Clay coatings are added to the lidding material to enhance
printing.
 Heat-sealing and printability are both important considerations
in blister packaging, and the lidding material must offer the best
workable compromise.

Aluminum
 Primary component of lid stock is aluminum and its gauges
varies from 18-25 µm (0.0078 to 0.001 inch).
 Side of aluminum foil laminate in contact with the product
provides the heat sealable layer that forms the seal to the
blister material.
 Different designs of lid stocks are available and selection of a
particular design depends on how the packages will be used.
 Standard designs includes
 Peelable ,
 Push-through and
 Child-resistant

Peelable foil
 Peelable foil can be peeled away from the blister.
 With the peelable foil lid stock, which is used in
conjunction with blister tooling, a three step process is
required to open the blister.

Child resistant foil
 For child-resistant peelable foil, a layer of polyester with the
appropriate adhesives would be added.
 This type will gives more protection for the kids against
deliberate consumption of medicines.
 The blister cavity must be separated from the rest of the blister card.
 The paper and the polyester layers are pulled back from an
unsealed area.
 The product is pushed through the remaining aluminum foil.

Push-through foil
 Two commonly used types of Push-through foil are-one with a
paper outer layer separated from the aluminum by a layer of
adhesive and one without paper.
 The paper outer layer serves as an aesthetic and makes it
possible to print on the back of the blister.

Comparison of lidding material

3. Heat seal coating
 Heat-seal coatings provide a bond between the plastic blister
and the printed lidding material.
 For blister packages, heat-seal coatings are perhaps the most
critical component in the entire system.
 The appearance and physical integrity of the package depends
upon the quality of the heat-seal coating.
 These solvents or water based coatings can be applied to rolls
or sheets of printed paperboards using roll coater or
flexographic methods, knives, silk screenings or sprays.
 Whatever the system, it is essential that the proper coating
weight be applied to the lidding material for optimum heat
sealing results.

A successful heat-seal coating for blister packages must
exhibit;
 Good gloss,
 Clarity,
 Abrasion resistance,
 hot tack
 must seal to various blister films.
Heat seal coating (cont.)

Hot tack
 Hot tack is particularly important because the product usually is
loaded into the blister and the lidding material heat sealed in
place (face down) onto the blister.
 When the package is ejected from the heat-seal jig, the still-
warm bond line must support its entire weight.
 The heat seal coating must precisely match the lidding material
and the plastic material of the forming film.
 Precisely match means that with pre determined sealing
parameters, a permanent sealing effect between the lidding
material and the forming film must be guaranteed under any
climatic condition.

4. Printing Inks
 Printing inks provide graphics and aesthetic appeal.
 They can be applied to the lidding material by letterpress,
gravure, offset, flexographic, or silk-screen printing processes
 Printing inks must
 Resist heat sealing temperatures as high as 300 °C without
showing any discoloration or tackiness.
 Sufficiently resist abrasion, bending, and fading.
 Be safe for use with the intended product.
 Comply with FDA recommendations.

Blister Packaging machine
1. Thermoform blistering machine
2. Cold form blistering machine
3. Thermo-cold complex blistering machine

Thermoforming
 In the case of thermoforming, a plastic film or sheet is unwound
from the reel and guided though a pre-heating station on the
blister line.
 The temperature of the pre-heating plates (upper and lower
plates) is such that the plastic will soften and become pliable.
 The warm plastic will then arrive in a forming station where a large
pressure (4 to 8 bar) will form the blister cavity into a negative
mold.
 The mold is cooled such that the plastic becomes rigid again and
maintains its shape when removed from the mold.
 In case of difficult shapes, the warm film will be physically pushed
down partially into the cavity by a "plug-assist" feature. Plug-assist
results in a blister cavity with more uniform wall distribution and is
typically used when the cavity size and shape is larger than a small
tablet.

Advantages of thermoforming blister pack:
The most basic material for the forming web is PVC or Polyvinyl
Chloride, for ease of thermoforming and low cost.
The product can be visually examined through the transparent
plastic. The faulty blister card can be rejected via the inspecting
camera or naked eyes.
Because the cavity or pocket contain the item snugly, it can adopt
the universal feeder which consists of circular brushes and
planetary agitators that sweep the products into blister pockets.
Parts are not required for different formats. This feeder is noted for
its low cost and ease of operation.

Disadvantages of thermoforming blister pack:
The protective properties are not strong because of the PVC’s
poor barrier against moisture and oxygen ingress.
Not suitable for light-sensitive drugs because of the
transparency of PVC.

Thermoforming
Thermoforming process consists of four basic stations
where following operations occur
1. Forming
• Pre heating
• Thermoforming
• Cooling
1. Filling (Loading)
2. Sealing
3. Finishing

Schematic Representation of Thermoforming

Pre-heating
 Heating station is present only in thermoform & thermo-
cold form blistering machines.
 Prior to entering forming station, reel-fed base (tray)
web (blister material) passes through the heating unit.
 Heating is achieved either by
 Infra-red heaters
 Contact heaters
 The temperature , based on the blister material used and
on the speed at which that material travels through the
heating station , is a critical parameter for optimal
performance .

Forming
 At the forming station the blister material is heated to the
point where the plastic softens sufficiently to allow the cavity
to be formed by
 Mechanical forming between male and female moulds
 Vacuum or negative pressure-which draws the softened film over or
into a mould

Forming (Cont.)
 Pressure-in which compressed air forces the film over or into
a mould
 Combination of the two
 For an identical blister shape, pressure plus plug
assistance generally gives most uniform blister.

Cooling
 The moulds into which the plastics is formed can be
cooled by air, water or chilled water
 The cooling station cools the films after the forming
process. (Laminates containing aluminum do not need
to be cooled.)

Filling (Loading)
 Here product is loaded into blister cavity either manually or
with the aid of feeding mechanism
 Uncoated tablets or capsules are normally fed from vibratory
bowl via channels or tubes by gravity.
 Vacuum extraction is frequently applied to the bowl tubes etc
to minimize powder and tablet chips which may finish up in the
seal or tray.
 The critical parameter is the proper filling of formed blisters

Sealing
 At this station, lid stock is sealed to filled blister cavity, using
heat and pressure.
 The critical parameters to be considered at this station are
temperature, pressure .
 The lid stock material is staged on a roll above the blister cavity
and may be preprinted or printed on line.
 Lot no. and expiration dates may be applied at this point.
 Preprinted lid stock materials will require a print registration
system to control the position of the printing relative to the
blister cavity.
 The critical parameters at this part of station includes legible
and correct labeling.

Finishing
 Includes embossing, perforation and cutting.
 Embossing involves application of lot no. and expiration date to
package. This process is carried out at printing station.
 Steel type is used to emboss information on the edges of the
blister package.
 At Trimming station, the blisters are cut into individual unit
 Embossing, perforation, cutting process should not
compromise blister lid or seal. Package integrity and quality of
embossing are critical parameter in the process.

Cold forming
 The aluminum will be elongated and maintain the formed shape.
In the industry these blisters are called cold form foil (CFF)
blisters.

Advantage of cold form foil blisters is
 Use of aluminum offers a near complete barrier for water and
oxygen, allowing an extended product expiry date.
Disadvantages of cold form foil blisters :
The slower speed of production compared to thermoforming;
The package is opaque, making the inspecting system, which
rejects the faulty blister card, complicated and costly.
The cost of cold forming aluminium film is higher than PVC.
The larger size of the blister card (aluminium cannot be formed
with near 90 degree angles) increases the material cost.
Because the cavity or pocket is larger than the drug, the feeder
should be dedicated. this increases the cost and difficulty of
operation.

Operation of Cold Forming
The sequence involves;
Installing the Aluminium Foil,
Cold forming it into blister cavities via punch pins,
Loading the blister with the product,
Placing lidding material over the blister,
Heat-sealing the package.
Cutting into individual blisters

Types of Cold forming processes
1. Clamping the material and carrying out a true punch action
where the non-held area is extended (stretch forming).
2. Taking a foil which has been embossed or finely creased; can be
extended by air or mechanical pressure without showing flex
cracks.
3. Taking a reel of material with regular cross-direction slits (as used
on suppository machine).
4. A male/female mechanical forming operation is carried out
between each slit. This mechanical operation forms the foil and
the slit area moves (opens), thereby preventing any high degree
of stress
5. Latest innovations include a double forming operation which
reduces the tray size to 20% (Advanced Forming Technology
(AFT) process). These tend to use Teflon stretching dies.

Larger size of the cold forming blister pack compared to
thermoforming blister pack.

Thermo-cold forming
Example: ALU-Tropical Machine
Operation:
The sequence involves;
 Heating the plastic,
 Thermoforming it into blister cavities,
 Loading the blister with the product,
 Placing lidding material over the blister,
 And heat-sealing the package.
 Installing the aluminium foil
 Cold forming it into blister Pouch & seal it on
thermoformed blister to give extra protection,
 Cutting into individual blisters

 Strip packs present an alternative form of pack for a
unit dosage.
 Strips can be produced from single or multi-ply
materials, provided the two inner plies can be sealed by
heat or pressure (e.g. cold ‘self-adhesive’ seal).
 Materials can range from relatively permeable plies to
those which incorporate a foil ply of sufficient thickness
(and effectiveness of seal) that an individual hermetic
seal is produced for each dosage.
 Usually produced at lower speeds and also occupy
greater volume than blisters.
59
Strip Packs

Consists of one or two plies, made from
 Regenerated cellulose
 Paper
 Plastics,
 Foil or any combination
--------------an item is inserted into a pocket area against
a recess in a heated roller
Strip Packs (cont.)

 Heat Sealable Cellophane
 Heat Sealable Polyester
 Paper / Polyethylene / Foil
62
Strip forming material

 Strip packaging offers a more user-friendly packaging
solution than bottled tablets and capsules.
 It provides economical packaging solutions for highly
sensitive drugs.
 It is a strong and perfect pharma packaging material for
protection and distribution of the drug.
 Strip packaging is the exact size of the capsule or the
tablet in question. It keeps the pills and capsules
organized, separated and safe.
 Strip packaging allows one to consume a single tablet
without touching the packaging of the other tablets.
Advantages of Strip Packaging

 Basically a strip pack can be formed by introducing an item which
extends a pocket area during insertion or by a preforming
operation prior to filling.
 As the latter method gives less strain (or more controlled forming)
to the pocket area and reduces the material needed by 20–35%,
 Either one or both sides of the plies may be mechanically formed,
but this process can only be applied to materials which will
‘stretch’ without tearing.
 Strip packaging machines are far simpler and smaller than blister
packaging units, usually simply consisting of a feed system,
product insertion plus heat sealing, and a guillotining operation to
size.
 Feed is usually via a vibratory bowl with feeding tracks (usually up
to a maximum of sixteen).
 Alternatives are a rotating table plus drop or sweep.

 Most machines employ a vertical feed (gravity drop) but
occasionally the web is run horizontally with a platen type sweep.
 The pocket area is created by recesses either in a platen or more
usually in a heat sealing cylinder, where a circumferential point seal
is made between two intermeshing cylinders.
 As with blister packs, the maximum speed depends on the size of
the item and gravity. A maximum speed of 250–300 per track is
likely with a 325 mg (five grain) type of aspirin product.
 Removal of powder, chips, etc. is achieved by vacuum extraction.
 Cutting of the emerging web is invariably done by either a scissors
or guillotine motion or rotary die cutting.
 Additional stages which can be incorporated into the machine
include printing, perforating, batch coding, etc.

 As distinct from blisters, perforation does not usually add to
the seal width, as pocket seals are nominally 5 mm or more.
 Most machines use two separate webs but occasionally a
single centrally folded web may be employed.
 Strip packaging is closely allied to sachet packing and in
certain cases it is difficult to differentiate between the two.
 Two different plies can also be used (top and bottom)
provided the sealants are compatible.

Strip designs
 Strip designs are very basic, as the emerging units are
invariably rectangular or square strips.
 The pocket portion can, however, be round, oval or square.
 The pocket area is critical to the diameter, shape and thickness
of the product.
 If the pocket is too ‘tight’, tearing, perforation of the pocket
periphery or wrinkling of the seal area may occur.
 The seal width may be as low as 4 mm, but usually 5 mm and
above is employed. If the seal area is likely to wrinkle or crease
then wider seals may be necessary.

Materials of Construction/
Type
Critical Properties Area of use
PVC 200/250/350 Low barrier / Simple unit
pack / Aesthetic
Stable products like Paracetamol,
Co-trimoxazole, certain softgel capsules etc.,
PVC / PVdC (250/40) Low barrier better than PVC Products not very sensitive to moisture, gases
and with moderate self life- Multivitamin tablets
and capsules
PVC / PVdC (250/60)/ (250/90)/
(250/120)
Good barrier Moderate to high sensitive range of products,
certain FDC/ Enzyme products
PVC / PE / PVdC (200/25/60)/
(250/25/90)(300/30/90)
Good barrier Quite high sensitive range of products – 4
FDC(RHZE)
Ultrasafe Duplex High barrier/economical Quite high sensitive range of products
Ultrasafe Triplex High barrier/economical Quite high sensitive range of products
PVC/Aclar (PCTFE) (10μ to
100μ)
Excellent barrier Extremely sensitive range of products
PVC/COC, PE/COC Excellent barrier Extremely sensitive range of products
OPA/Al foil/PVC Excellent barrier Extremely sensitive range of products

Materials of Construction/ Type Critical Properties Area of use
Alu/Alu Excellent barrier Extremely sensitive range of products
OPA/Al foil/PVC
(OPA- Oriented polyamide)
Excellent barrier Cefuroxime Axetil tablets,
Levocetirizine Tablets,
Alu/Alu with desiccant Excellent barrier Extremely moisture sensitive range of
products
Aluminium foil with HSL (Hard tempered)
0.02 / 0.025
Excellent barrier Lidding foil for blister packing
Aluminium foil
(Hard tempered with special coating)
Excellent barrier Lidding foil for COC
Aluminium foil / poly (30 –40 microns
(soft tempered)
Excellent barrier For strip packing use of very sensitive
range of
products – Omeprazole Capsules,
Ranitidine
Tablets etc.,
Aluminium foil / VMCH (30 –40 microns
(soft tempered)
(VMCH- Vinyl Acetate - Maleic Acid - Vinyl Chloride
Copolymer)
Excellent barrier For strip packing use of dark colored
sugar
coated tablets.
Paper /Poly Very low barrier / Simple
unit
pack / Aesthetic look
Very economical pack for very stable
products.
Paper/ AL/HSL (heat seal laquer) Excellent barrier For Child resistance blisters pack

Choosing suitable polymer/blister packs
Comparative WVTR 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 250 03
Polypropylene 01
PVC / PVdC (250/40) 0.75
PVC / PVdC (250/60) 0.5
PVC/10μ PCTFE (Aclar) 0.45
COC 190 μ 0.35
PVC / PE / PVdC (250/25/90) 0.31
COC 240 μ 0.28
COC 300 μ 0.23
COC 350 μ 0.2
CFF (Alu/Alu) PVC/Alu45/OPA25 0

Representative Cost Comparison for Packages
Containing 30 tablets
Packaging Material Material Cost
($)
Labor Cost ($) Total Costs ($)
Glass bottle 0.51 0.70 1.21
Plastic bottle 0.125 0.70 0.825
Blister Pack 0.07 0.25 0.32
Reference: Pharmaceutical Technology, November 2000

ALU-ALU PackagingALU-ALU Packaging

Introduction
 Alu Alu Foil is an excellent multilayered structure
designed for high sensitive range of Pharmaceutical
and generic medicines which are highly hygroscopic
or light sensitive and cannot be suitably packed with
barrier plastic films.
 The structure is an optimized combination of
aluminium foil and polymeric films with the alumina
layer sandwiched between an inner heat sealable
polymeric film and outer supportive malleable film.

Introduction (cont)
 Alu-alu blister represents the new generation in
pharmaceutical packaging, its the material with best
barrier performance at present, and can absolute
resist vapor, oxygen and UV rays, good performance of
aroma barrier.
 Each blister is a single protection unit, no effect to
barrier after opening first cavity, especially suitable for
drugs that easy to be affected in wet regions and
tropics.
 Alu-alu blister can be shaped in various appearances
by changing mold, simultaneous, its glorious silvery
white luster no doubt can promote selling.

Aluminium Foil for Pharmaceutical Packaging
(BIS Specification)
 Bare Blister Pack Foil
Bare foil (of thickness 20-25 µ without any lamination or coating)
used for blister pack application for pharmaceutical packaging
usually after coating.
 Coated Blister Pack Foil
Bare foil (of thickness 0.20-25 µ) with one side coated with heat
seal lacquer and the other side with primer or printed, used
for blister pack application in pharmaceutical packaging.
 Bare Pharma Strip Pack Foil
Bare foil (of thickness 30-40 µ without any lamination or coating)
used for strip pack application for pharmaceutical packaging.

Benefits of ALU ALU Packaging
 100% Barrier against water vapour, gases, light etc
 Excellent Thermo-formability
 High degree of Thermal stability
 High Malleability for deep drawing blister cavities
 Effective anti counterfeit packaging

Cold forming for ALU ALU
 The aluminum will be elongated and maintain the formed
shape. In the industry these blisters are called cold form foil
(CFF) blisters.
 Advantage of cold form foil blisters is
 Use of aluminum offers a near complete barrier for water and oxygen,
allowing an extended product expiry date.
 Disadvantages of cold form foil blisters are:
 the slower speed of production compared to thermoforming
 the lack of transparency of the package
 The larger size of the blister card (aluminum can not be formed with near 90
degree angles).

Manufacturing of ALU ALU Blister

Evaluation of Blister/Strip
1. WVTR Studies
 A desiccant (usually silica gel or magnesium chloride) is placed
inside the blister rather than the actual pharmaceutical product.
 This standard was introduced decades ago by U.S. Pharmacopeia.
 These blisters to be placed in an environmental chamber at
constant temperature and humidity conditions (there are several
combinations, but the most common one is 23°C and 75%RH).
 The weight of the sample blister is then measured at certain
intervals of time for 28 days.
 From the weight gained and the number of individual blisters in
the pack, the Water Vapor Transfer Rate (WVTR) is determined in
terms of grams of water per day per blister.
 A typical blister pack with two cavities and silica gel desiccant is
shown in above Figure

1. WVTR Studies (cont.)
 By today’s standards, this traditional U.S.P. method is time
consuming and prone to errors.
 Therefore, several companies are improving the effectiveness of
their testing by using Gravimetric Sorption Analyzers to measure
the rate of water permeation.
 The improved procedure consists of hanging several blisters filled
with desiccant inside sample cavity and monitoring its weight
under selected temperature and humidity using precision
microbalance design.
 Typically, this testing is done at 25°C at 60%RH, 30°C at 65%RH
and 40°C at 75%RH and the experiment is run until steady state
conditions are reached in each case.
 An experiment might last from 3 to 5 days depending on the
permeation properties of the particular blister material.
 This testing protocol is based on the methods issued by the (ICH).

2. Vacuum tests
 Immerse the test package in a container containing colored
water (15–25°C) and place the container in the vacuum
chamber.
 Apply the appropriate vacuum of
 33 kPa (250 mm of mercury) for strip packages or
 24 kPa (180 mm of mercury) for blister packages, for 30 s.
 Restore atmospheric pressure and remove the container from
the vacuum chamber.
 Remove the test package from the container and blot off the
excess water. Examine the package for ingress of water into the
pockets.

Blister / Strip Defects
Common defects include
Pin-hole
Seal defect
Curls of trays
Sharp edges
blocking

Pin Holes
 Foil of 0.03 mm is pin hole free
 Foil of 0.0177 mm can be consider commercially free for
most purposes.
 0.009 mm foil may contain 100-700 pin holes/m2.
 Permeation through pin holes can be reduced by lamination.

Seal Defects
Seal defects occurs due to
Improper alignment of foil & film during sealing.
Excess heating
Quality of material

Curl Of Trays
 Occurs due to heat-sealing operation
 Amount of curl depends partially on type of
machine employed, the type of web and
design of tray.
 Curl occurs due to different co-efficient of
expansion for foil and film plus film
shrinkage due to molecular reorientation.
REMEDY:
 By incorporating thermoformed ribs in the
tray
 Reversing the web curvature by passing over
a tension roller .

Sharp Corners & Blocking
SHARP CORNERS
It occurs during punching out or die cutting
If not handled carefully may penetrate pockets of trays.
BLOCKING:
During manufacturing two adjacent layer of film stick
together

Damaged Tablets
 In Blister packing the dimensions of the tablets
plays a very important role.
 It invariably gets jammed in the transport chutes
thus producing unfilled / half filled / broken tablets
in to blisters.
 This dimensional check improves the efficiency of
the Blister packing machine

Exercise
 Identify Blister, Strip & ALU-ALU Pack in
the next slide?????????

References
Pharmaceutical. Packaging Technology, Dean DA, Evans ER and Hall IH, Taylor & Francis
Inc., 2000.
Pharmaceutical Packaging Handbook. Bauer E, Taylor & Francis Inc., 2009.
Pharmaceutical Technology, November, 2000
www.slideshare.com
www.encyclopedia.com
www.google.com

Blister & strip packaging

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