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TABLET HARDNESS

TESTER

Instrumental Seminar

Dr. Vikas Saroch17/04/2009 Dept. Of Rasashastra

Dept. Of Rasashastra 2

CONTENTS

INTRODUCTION

TABLET HARDNESS

HISTORY

MODERN INSTRUMENTATION

WHY TEST

MEASURING UNIT

TEST METHODS

INSTRUMENTS

CONCLUSION

REFERENCES17/04/2009

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INTRODUCTION

The compressed tablet is one of the most popular dosage forms .

About one-half of all prescriptions dispensed are for tablets.

Usually one considers a compressed tablet as an oral medication.

Tablets have many other uses. The sublingual tablet, the pellet, the

wafer, and the vaginal insert are manufactured by the same procedure as an oral tablet.

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TABLET HARDNESS

Defined as “ The force required to break a tablet in a diametric compression test.”

Hard enough to withstand mechanical stress during packaging, shipment, and handling by the consumer.

Section <1216> of the USP 24/NF19 outlines a standard tablet friability test applicable to manufactured tablets.

Most compounding pharmacy would not have the apparatus specified in Section <1216>. However, there are several hand operated tablet hardness testers that might be useful.

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TABLET HARDNESS

There are various devices to test the hardness of the tablet :

Monsanto tester Strong- cobb tester Pfizer tester Erweka tester. Schleuniger tester

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HISTORY

The first tablet hardness tester was introduced around the mid-1930s.

Purely mechanical device and is still manufactured today.

Force was applied with a screw thread and spring until the tablet fractured and the hardness was read from a sliding scale graduated in ½ kg increments.

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Contd…

This was followed by the so-called Strong-Cobb tester, introduced around 1950.

The testing force was generated by a manually operated air pump and the tablet breaking force was measured on a dial graduated in 30 arbitrary units which were designated as Strong-Cobbs.

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Contd…..

The results given by the Strong-Cobb tester were not consistent with those of the earlier tester.

Electro-mechanical tablet hardness testing machines were later introduced and have evolved into electronic test instruments such as those produced by Engineering Systems.

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Modern instrumentation

Contain a motor drive system to

generate the force.

Automatically detect the tablet.

Fracture displaying the force in a

variety of units.

Measurements can be printed and /

or downloaded to a computer .17/04/2009 Dept. Of Rasashastra

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need for test

Too ‘soft’ tablets can disintegrate in transport.

Too ‘hard’ tablets could damage teeth.

Tablet strength testing is necessary for both,

research & development of new formulations, and

for quality control.

The test instruments should provide accurate

results and output these results in standard units.

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MEASURING UNIT

Newton (N) – The Newton is the SI

unit of force and is the unit that

should be used for tablet hardness

testing. 9.807 Newton = 1 kilogram

Kilopond (Kp)

Strong Cobb (Sc)

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Contd…

Strong-Cobb (SC) – The Strong-Cobb is

a legacy of the first tablet hardness

testing machines.

An arbitrary unit

Never recognized by the SI system.

1.4 Strong-Cobs are thought to equal

about 1 kg17/04/2009 Dept. Of Rasashastra

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TEST METHODS

The standard method used for tablet hardness testing is compression testing.

The tablet is placed between two jaws that crush the tablet. The machine measures the force applied to the tablet and detects when it fractures.

This method is used for research & development and for quality control.

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Monsanto Hardness Tester

Developed approximately 50 years ago.

Consists of a barrel containing a compressible spring held between two plungers.

The lower plunger is placed in contact with the tablet ,and a zero reading is taken.

The upper plunger is then forced

against a spring by turning a threaded bolt until the tablet fractures.

As a spring is compressed, a pointer rides along a gauge in the barrel to indicate the force. The force of fracture is recorded, and zero reading is deducting from it.

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Monsanto Hardness Tester

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Strong-cobb tester

Consist of a plunger activated by pumping a lever arm, which forces an anvil against a stationary platform by hydraulic pressure.

The force required to fracture the tablet is read from a hydraulic gauge.

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Pfizer tester

Operates on the same mechanical principle.

1st pliers handles are squeezed.

Tablet is compressed between a holding anvil and a piston connected to a direct force reading gauge.

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TABLET HARDNESS TESTER

Can be fitted

on either bench

or tablet ling

machine.

Includes :

Engineered

Dial Gauge,

Aluminium

Body .

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3 in 1 - Type PTB 311E

Test : Thickness,

Diameter or Length and Hardness of the same Tablet

Hardness: 2.0 - approx. 330 N (Newton)

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Tablet Hardness Test Type : PTB 302

Test the Hardness

of tablets, cores,

capsule shaped

samples.

Hardness:

2.0 - approx. 330

N

(Newton) - 550N

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CONCLUSION

All the different varieties of testing machines would give the same results (if used on the same batch of tablets).

Machine ‘accuracy’ would equal Machine ‘resolution’.

All pharmaceutical companies would use the same SI unit of measurement (N or kg) and the same constant (6 mm/min) test speed.

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References

www.pharma-test.com www.indiamart.comwww.pharmaceuticalonlin

e.com

www.google.com

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THANK YOU

17/04/2009