Saturday, February 27, 2021

Blister Packaging|Pharmaceutical Packaging

Blister packaging is one of the most common and widely used packaging in pharmaceutical industries for tablets, capsules, pills or lozenges.

Blister packaging is a type of packing in which the product is placed in pockets or cavities and is protected by a covering.

Blister pack is also known as Push Through Pack (PTP) because we can remove the product by pushing it through the covering or lidding foil and it is used for unit-dose packaging in most of the countries of the word but in the USA it is used for physician samples or OTC  and remaining doses are dispensed by bulk plastic containers .


Advantages of Blister Packaging

Advantages of  Blister packaging are as follow,


Protection

Blister packaging Protect the product from 

  • Humidity

  • Gases

  • Temperature

  • Light


Light Weight

Blister packaging is lightweight as compared to other packaging like glass bottles and plastic bottles.


Intact

Blister packs provide the option to remove only one dose which is to be taken so other products are intact inside sealing and are protected from exposure to the environment and chances of product contamination are minimised.


Tamper Resistance

Blister packaging provides tamper resistance.


Cost 

The cost of blister packaging is low as compared to glass and it meets regulatory requirements


           Blister Packaging


Components Of Blister

Following are components of a blister


  1. Cavity Forming Film/Foil

  2. Lidding Foil


1.Cavity Forming Film

  • Cavity forming film or foil is a material that is used to form pockets or cavities.

  • In pockets or cavities product is placed.


Method Of Cavity Formation

Pockets or cavities can be formed by two methods

  • By Application Of Heat

  • By Application Of Pressure


Types of Cavity Forming Films

Based on the method of manufacturing of pockets following type of forming films are used

  • Thermoforming Film (By Heat)

  • Cold Forming Film (By Pressure)


Thermoforming Film

Thermoforming films are used to form pockets or cavities by application of heat.


Procedure

  • For cavity formation by using thermoforming foil, the roll of foil is unwound and passes over the heating plates.

  • Heat softens the foil.

  • This softened foil is then passed over the forming station or cavity plate.

  • Air Pressure is applied from the lower forming plate which pushes the soft forming film in the dies of the upper forming plate and pockets or cavities are formed.

  • This is then cooled by circulating water below the plates so the soft sheet becomes rigid and pockets are not deformed.

  • The product is fed in the pockets and is sealed by the lidding material.


Materials Used For Thermoforming Cavities

Following materials are used for thermoforming cavities.


  • PVC

  • PVDC

  • PVDC

  • PTCE

  • COC


PVC

  • PVC is polyvinyl chloride and it is the most widely used material as a thermoforming film.

  • It can easily be softened by heat and form good pockets to retain product

  • It is cost-effective.

  • In pharma PVC used do not have any plasticizer so it is also known as rigid PVC or RPVC.

  • The rigidity of PVC is such that we can easily push our product from the pockets by applying little pressure with the thumb.

  • In pharma, PVC is used having a thickness of 200 microns to 300 microns.


Disadvantages of PVC

  • Even though it is a commonly used material for blister formation in pharma, its barrier property for moisture and oxygen is low.

  • Water Vapor Transmission Rate (WVTR) of a PVC sheet having a 250-micron thickness is  3g/m²/day  and it is measured at the following conditions


  • Temperature 38°C

  • Relative Humidity 90%


  • The Oxygen Transmission Rate OTR is 20 ml/m²/day.

  • The barrier property of PVC can be increased by coating the PVC with the Following.


  • PVDC

  • PCTFE

  • COC


  • Pigments or UV filters can also be used on PVC sheets.


PVDC

  • PVDC is polyvinylidene chloride and is used to enhance the barrier properties of PVC for Moisture and oxygen penetration.

  • PVDC is applied as an aqueous coating over the PVC.

  • The weight of PVDC is expressed as grams per square meter or gsm.

  • The strength of the barrier depends upon the weight of the coating material applied over PVC.

  • It is a less costly method to enhance the barrier properties of PVC.


 PVDC coated films are available in two forms

  • Duplex Form

  • Triplex Form


Duplex Form

  • Duplex forms contain PVDC and PVC as PVC/PVDC.

  • The weight of coating layers and WVTR, OTR  in the duplex are as follow ranging f


  • PVC 250-micron PVDC 40 gsm having WVTR 0.65 g/m 2/d and OTR 1.0 cc/m²/d.


  • PVC 250-micron PVDC 120 gsm

having WVTR 0.25g/m²/d and OTR 0.1 cc/m²/d.


Triplex Form

  • Triplex forms contain PVC/PE/PVDC.

  • PE is polyethene.

  • In triplex form, PE is in between PVC and PVDC.

  • PE forms a flexible layer between rigid PVC and PVDC and helps to form deep cavities.

  • The triplex form is used where very deep cavities are required to form by heat.

  • The weight of coating layers in a triplex is the same as in duplexes  with the addition of the PE layer and are as follow ranging from


  • PVC 250 micron 

  • PE      25 micron

  • PVDC 40 gsm 

to

  • PVC   250 micron 

  • PE       25   micron

  • PVDC 120 gsm


PCTFE

  • It is a polychlorotrifluoroethylene.

  • It is laminated over PVC to enhance its barrier properties.

  • 15 micron to 150 micron PCTFE film is used for lamination of 250 micron PVC films.

  • It also exists as duplex and triplex form 

  • The duplex form is PVC/PCTFE.

  • Triplex form is PVC/PE/PCTFE/.

  • PCTFE films have the least Water vapour permeation.

  • It is the most expensive film available for thermoforming blisters.


COC

  • COC is a cyclic olefin copolymer.

  • COC is used to provide a barrier for moisture in combination with PE or Polypropylene PP.

  • COC differs from PVC because it consists of hydrogen and carbon and does not contain chlorine or other halogens.


Cold forming Film/Foil

  • Cold forming films are used to form pockets or cavities by application of pressure.

  • In cold forming, the film or sheet passed over the forming station.

  • In this forming station, the upper plate has Teflon punches which press the foil or sheet in pockets of the lower plate with high pressure.

  • When the pressure has released the pockets of foil are formed.

  • The product is fed in the pockets and is sealed by the lidding material.


Advantage


  • Cold forming foil provides more protection to the product.


Disadvantage

  • In Cold forming blisters, products are not visible to consumers.

  • Machine Speed is slow for cold forming blister formation.

  • Usually, the size of cold forming blisters is large so a large secondary pack is required.

  • The cost of cold forming foil is high as compared to thermoforming foil.

  • Cold forming blisters may damage if not handled well.


Materials For Cold Forming Cavities

Aluminium foil is used for cold forming cavities.


2.Lidding Foil

Lidding foil is used to form a covering over the cavities or pockets.

  • Lidding foil forms a protective sealing over the forming foil.

  • Usually, thin aluminium foil of thickness 18-25 micron is used.

  • The inner side of the lidding foil which faces towards the product has a heat sealing coating to form a sealing bound with forming foil on heating.

  • The outer or upper side of the lidding foil has a printed pattern and may contain product identification marks.

  • The ink used for printing should be Stable at high temperature and should not fade.

  •  Ink used should comply with FDA guidelines.

The following pattern of lidding foil may be used 

  •  Push Through 

  •  Child Resistance

  •  Peel Off


Also Read: 

Sunday, February 21, 2021

Glass Packaging In Pharmaceutical Industries

Glass is a good packaging material for pharmaceutical products like tablets, capsules,syrup and suspension in glass bottles and sterile products in the form of ampules or vilas.Glass was discovered in 3000 BC and from that time it is widely used in  the packing of pharmaceutical and food products.

Glass is prefered pharmaceutical packaging material because of its high level of barrier property for moisture and gases.


 Manufacturing & Composition Of Glass 

  • The main component of glass is silicon dioxide or sand or silica and it also contains soda ash,limestone and cullet.

  • Cullet Is broken glass which is used in the manufacturing process and mixed with batch and acts as a fusion agent.

  • Glass  is prepared by heating the sand or silicon dioxide,limestone (as calcium carbonate),soda ash (as Sodium carbonate) and cullet.

  • On heating at high temperature a molten mass is produced which is then cooled and converted into glass.

  • Others ingredients used are are as follow


  • Selenium or Cobalt Oxide

  • Lead Oxide

  • Alumina

  • Boron

  • Arsenic Trioxide and Sodium Sulphate

  • Colourants


Selenium or Cobalt Oxide

Selenium or cobalt oxide give better clarity to the glass.


Lead Oxide 

Lead Oxide gives clarity to glass but it also makes the glass soft.


Alumina

It Increases glass hardness,gives clarity and durability.


Boron 

Boron results in low thermal expansion of glass.It also gives high heat resistance to the glass.


Arsenic Trioxide and Sodium Sulphate

These are used to reduce blistering of glass.


Colourants.

Different colors and materials are used to give a specific color to glass for different purposes e.g amber color glass is used for pharmaceutical packaging of those products which are degraded by the light.


Glass Packaging In Pharmaceutical Industries.


Amber Color Glass

For amber color it contains carbon and sulphur or iron and manganese.


Blue glass

It contains Cobalt with copper


Green Glass

It contains Chromium with iron and Manganese


Advantages of Glass

Following are some main advantages of glass containers to used as pharmaceutical packaging material


Compatible

Glass is compatible for most of the pharmaceutical products  so it can easily be used for packaging of pharmaceutical products.


Impermeable

Glass provides strong barriers for gases and moisture penetration so keep inside products stable.


Heat Stable

Stable for holding hot products.


Visibility

Clear Glass containers allow visual inspection because the product is visible.


Light Protection

Amber color glass is used to protect the light sensitive products.


Sterilization

Product packed in glass packaging material can easily be sterilized.


FDA Approved 

Glass as a packaging material is approved by the FDA and it does not deteriorate in storage with passage of time.


Dis-Advantages Of Glass Packaging

Following are some disadvantages of glass packaging,


Cost

Cost of glass packaging material is high.

Cost of transportation to market after packaging is also high.


Weight

Glass is Heavy weight so difficult for handling.


Brittle

Glass is Brittle so chances of breakage are high during transportation.


Product Loss

Product loss occurs in case of damage to glass  packaging material.


Ion Leaching

Leaching of ions may take place.



Types Of Pharmaceutical  Glass

Following are types of glass 

  • Type I Glass

  • Type II Glass

  • Type III Glass

  • Type IV Glass/Type NP


Type I Glass

  • Type I glass contains a high level of boric oxide so it is also known as borosilicate glass.

  • The Type I glass is Highest grade Of Pharmaceutical glass.

  • Type I glass consists of 

    • Boric Oxide

    • Aluminium Oxide

    • Alkaline earth oxide

  • The type I glass is the most inert type of pharma glass having highest hydrolytic resistance and the lowest leaching effect.

  • It is highly resistant to heat.

  • Its Cost of manufacturing is very high.

  • It can easily be sterilized.


Uses of Type I Glass

Type I glass is used for packaging of 

Parenteral Products.

Type I glass is used for packaging of 

non- parenteral Products.


Type II Glass

  • Type II Glass glass is made of soda lime alkali glass.

  • Type II Glass contains Sodium Oxide and Calcium Oxide.

  • Type II Glass has average hydrolytic resistance.

  • Hydrolytic resistance of Type II Glass is increased by treating the inner surface of type II glass containers with sulphur dioxide.

  • Due to sulphur dioxide treatment the oxides on the surface react with sulphur dioxide e.g sodium oxide on the surface is converted into sodium sulphate and sodium sulphate can easily be removed from the surface by washing the glass containers.

  • This treatment with sulphur dioxide reduces the chances of ions leaching and  increases the hydrolytic resistance of Type II glass.

  • Type II glass is also known as treated soda lime glass or De-alkalized glass.


Uses of Type II Glass

Type II  glass are used for following

  • Acidic Aqueous Preparations

  • Neutral Aqueous Preparations

  • Parenteral Preparations

  • Non parenteral Preparations

Note:

Type II glass are not suitable for packaging of basic preparations.


Type III Glass

  • Type III glass is simple soda lime silica glass.

  • Type III Glass has moderate hydrolytic activity.

  • When type III is treated with sulphur dioxide it becomes type II glass.


Uses of Type III Glass

  • Type III Glass is used for non parenteral products.

  • Type III glass is not suitable for aqueous parenteral products.

  • Type III glass can be used for non aqueous parenteral products like sterile powders.


Type IV Glass Containers/Type NP

  • Type IV glass is also known as NP Non Parenteral general purpose soda lime glass.

  • Type IV glass has low hydrolytic resistance.

  • It is not suitable for autoclave.



Uses of Type IV Glass

  • It is not used for Sterile products.

  • It is used for topical products.

  • It is used for Oral Dosage forms.


Test For Glass Containers

Following test are used for glass containers

  • Crushed Glass Test

  • Whole Container Test

  • Water Attack Test

  • Chemical Resistance Test


References:


  1. Bentley's textbook of pharmaceutics

  2. Aulton's Pharmaceutics

  3. The Theory & Practice of Industrial Pharmacy

(Leon Lachman)



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100 MCQs to revise your pharmaceutical knowledge.