Closures

ClosuresPresented by: Anvita Jadhav M. Pharm (IP)

DEFINITION

• A closure can be defined as any method for

closing a pack so that the product is properly

contained & protected.

• A closure is a device that seals a product within a

pack but which can be removed to allow the

product to be accessed.

FUNCTIONS OF CLOSURE

Impact resistan

ce

Product-

closure compatibility

Control

Access

Positive seal

• Adequate seal until contents are required for the use

• The degree of seal tightness, is dependent on the product packed, closure, container, & seal desired, the resiliency of liner, the flatness of the sealing surface & tightness or torque with which the closure is applied.

• Many packages today are ergonomically designed systems capable of easy opening & dispensing & also affording critical access control.

• A tight seal with easy access

Positive seal

Access

• These controls are of two major types:

tamper-evident & child-resistant

• The closure mustn’t affect the contents of the container, nor be affected by them.

• Closures may be fitted with liner so that the closures material does not contact the content.

Control

Product-closure compatibility

• The closure is focal point of the container.

• Three communication forms include styling aesthetic, typography, & graphic symbols.

• The closure also have to be resistant to cracking & creep in order to withstand excess torque during screwing (as with screw caps) or other internal forces..

Verbal & visual communication

Impact resistance

THREADED CLOSURES

Continuous Thread Closures

Lug CapsMetal Roll-on

Closures

Continuous Thread Closures

• These are the most common type used for drugs.

• Screw threads on the bottle & on the closure mesh to form a mechanical bond that when tightened generates torque. Torque is the measured force that produces compression between the lip of the bottle or jar & the closure.

• Screw-threaded closures have a thread following a helical (spiral) pattern on the inside, which must be matched up with the thread on the neck of the container.

LUG CLOSURES• A lug closure is pressed down on the finish if the jar or

bottle & by using a very short quarter or half turn the closure fully engages the threads & achieves the torque necessary to seal the container.

• The difference with this closure is that it only contacts the thread in 2, 3, 4, or 6 point engagement locations around the circumference of the jar or bottle.

METAL ROLL-ON CLOSURES

• A roll-on closure takes advantage of a hard glass bottle finish (the threads at the top of the bottle) & the ductility of aluminium to produce a threaded closure on a container that does not require torque for application.

FRICTION-FIT CLOSURES

Bottle Crown

Closures

Snap-fit Closures

Press-on Closures

Vial Stoppers

Friction-fit closures rely on a number of different methods to create friction or some type of interference fit between the closure & the bottle.

BOTTLE CROWN CLOSURES

• They are used in pharmaceutical packaging on bottles for laxatives & other liquid products designed for complete consumption after opening.

• The steel or tinplate material crimped or folded into a number of indentations around the circumference of the closure.

• The closure is always lined, & it is applied over a ridge or formed area at the top of a bottle.

SNAP FIT CLOSURES

• Snap is any clasp or fastener that closes with a click.

• When the closure is in place, some resilient part of the closure system that is in contact with the container remains deformed, & provides a seal as it attempts to return to its original dimensions.

• For opening, the top is designed to pry off or break off, or have a built in dispenser.

PRESS-ON VACUUM CAPS

• Vacuum caps are a unique style of closure used to protect oxygen-sensitive products.

• In pharmaceutical applications they are found on metal containers for powdered infant formula.

• A vacuum is applied to a container, creating a partial vacuum in the container headspace below the closure.

VIAL STOPPERS

• Vial stoppers are elastomeric friction seals for injectable drug containers.

• The stopper acts as the seal in the mouth of the bottle & as a permeable self-sealing membrane that allows the needle on a syringe to be inserted for withdrawing the drug.

Various designs for stoppers are –

• Flanged plug elastomeric stoppers

• Flanged hollow plug with cutouts for lyophilized products

• Flanged elastomeric plug with plastic overseal

• Metal closure with an elastomeric disk

FLANGED PLUG ELASTOMERIC STOPPERS

• Most common vial closure for injectable drugs.

• The flange design of the elastomer plug maintains a tight fit between the plug & the vial neck & the flange & the end of the vial.

• The aluminium overaseal on the end of the vial locks this contact of the flanged plug in place.

• The aluminium band has a hole in the center, permitting access to the elastomer seal by a needle.

FLANGED HOLLOW PLUG WITH CUTOUTS FOR LYOPHILIZED

PRODUCTS

• The plug is partially inserted in the vial & the cutouts along the plug sidewall permit water vapor to exit the glass vial during the lyophilization (freeze drying) process.

• After completion of lyophilization, the plug is pushed the remainder of the way into the vial, creating the same type seal found in the first example with the flanged plug.

• An aluminum overcap is applied to the completed vial in the same way to lock the seal in place.

FLANGED ELASTOMERIC PLUG WITH PLASTIC OVERSEAL

• This type adds another feature to the closure process.

• A plastic overcap is fitted to the elasomer plug that has been put in place as described in the last two examples. The plastic overcap maintains the seal & the sterile conditions under the overcap where it contacts the plug.

• When the needle is inserted for the first use of product, the plastic overcap is removed & discarded.

METAL CLOSURE WITH AN ELASTOMERIC DISK

• An aluminium cap, similar to that described in the first two examples of plugged vials is applied.

• The difference is the elastomer is not a plug placed in the neck of the bottle, but a thin gasket applied to the bottom of the overcap.

• This membrane acts as a gasket for sealing & a plug for inserting the needle.

• The top of the closure is open exposing the membrane.

SPECIALTY CLOSURE

• There is a wide variety of specialty closures designed to make a product easier to use by the patient or consumer.

Flip-spout closures Push-pull closures

DISPENSING CLOSURES

• This closure has application & dispensing capabilities.

Closure with dropper Closure with pump dispenser

 CHILD-RESISTANCE CLOSURES

Child-Resistance Closures have become a common part of most pharmaceutical packages. Most of the packaging manufactures begin with the following assumptions -

• Children are very persistent & can use their teeth to open a package.

• Children’s teeth & fingernails are sharp & small enough to fit into any gap in the packaging.

• Children’s motor skills will not permit them to perform two or more motions at the same time.

• Children can learn quickly from watching adults.

• Children in these age groups cannot read instructions & cannot determine alignments of components.

The combination of downward pressure & simultaneous turning of the closure opens the bottle.

Press-turn closures

TAMPER-EVIDENT PACKAGING CLOSURES

• These closure has an indicator or barrier to entry which, if breached or missing, can reasonably be expected to provide visible evidence to consumers that tampering has occurred.

Breakable caps Tear bands

MATERIALS

• 1. Metal

• 2. Glass

• 3. Plastic

• 4. Rubber/Elastomers

METALS• Aluminium, aluminium alloys, tinplate, tin free

steel, stainless steel

• Metal caps are used today for general, vacuum & pressurized applications.

• Tinplate & tin-free steel are used in the production of continuous thread, press-on closures, lugs, overcaps & crown caps.

• Aluminium closures are primarily continuous thread caps & roll-on designs.

GLASS

• They are used in the stopper of the chemical reagent bottles in laboratories.

PLASTICS• They are unbreakable & light in weight.

• A liner is used in these closures.

Thermoplastics (polypropylene & polyethylene)• Light weight, versatility of design, good chemical

resistance to a wide range of chemicals & manufacturing processes.

Thermosets (phenolic & urea compounds)• Wide range of chemical compatibility & temperature

tolerances.

RUBBER/ELASTOMERS• Elastomers are primarily used as stoppers / closures

on parenteral containers.

Properties of elastomers :• Coring resistance (the ability to resist fragmentation

when penetrated by a needle)

• Solvent resistance

• Resistance to radiation

• Resistance to interaction with the packaged components

• Impermeability to gas & moisture

• Flexibility

• Common rubbers used in pharmaceutical packaging are –

• Butyl rubber

• Chlorobutyl rubber

• Natural rubber

• Silicone rubber

TESTS FOR THE RUBBER CLOSURE

• Sterilization test

• Test for extractable matter

• Fragmentation test

• Self sealability test

• Test for free sulfur content

• Test for reducing substance

• Test for heavy metals

LINERS

• A liner may be defined as any material that is inserted in a cap to affect a seal between the closure & container.

• A composite lining material consists of a backing & a facing.

• The backing is a material thick enough & compressible enough to produce a gasket effect on the lip of the container, creating a seal.

• The facing material provides functional performance such a gas barrier, moisture barrier, & isolates the closure from the contents of the container.

MATERIAL

Backing

• Paperboard,

pulpboard, chipboard,

cork, foamed plastic,

rubber etc.

Facings

• plastic film, foil, coated

foil,, paper laminations

etc.

LINERLESS CLOSURES

• Linerless closures eliminate the need for a liner.

• The seal of a linerless closure is achieved by molded embossments forming diaphragms, plugs etc.

REFERENCE

• Closures & Dispensing Devices for Glass & Plastic Containers, The Packaging User’s Handbook, Edited by F. A. Paine, Pg. No. 348 – 381, 1991.

• Edward J. Bauer, Chapter 6 Pharmaceutical Packaging Materials, Pharmaceutical Packaging Handbook, Pg. No. 268-271, 2009.

• U. K. Jain, D. C. Goupale, S. Nayak, Chapter 2 Packaging Materials, Pharmaceutical Packaging Technology, Pg. No. 36 – 40, 2008.

• Atul Kaushik, Bhaskar Chaurasia & Virendra Dhakar, Chapter 10 Closure & Liners, Textbook of Pharmaceutical Packaging Technology, Pg. No. 241 – 279, 2011.

• Edward J. Bauer, Chapter 10 Container Closure System: Completing All Type of Filled Pharmaceutical Containers, Pharmaceutical Packaging Handbook, Pg. No. 387 - 430, 2009.

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