Tablet hardness testing

<h2 id="list-of-common-hardness-testers">List of common hardness testers</h2>
There are several devices used to perform this task:

<ul><li>The <a href="/facts/Monsanto/6rVAaIXB">Monsanto</a> tester was developed 50 years ago. The design consists of "a barrel containing a compressible spring held between 2 plungers". The tablet is placed on the lower plunger, and the upper plunger is lowered onto it.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a><a class="footnote-ref" id="fnref:13" href="#fn:13">13</a></li>
<li>The Strong-Cobb tester forces an anvil against a stationary platform. Results are viewed from a hydraulic gauge.<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> The results are very similar to that of the Monsanto tester.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a></li>
<li>The <a href="/facts/Pfizer/1ADDanWs">Pfizer</a> tester compresses tablet between a holding anvil and a piston connected to a force-reading gauge when its <a href="/facts/Plier/LsKthwk2">plier</a>-like handles are gripped.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a></li>
<li>The Erweka tester tests a tablet placed on the lower anvil and a weight moving along a rail transmits pressure slowly to the tablet.<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a></li>
<li>The Dr.Schleuniger Pharmatron tester operates in a horizontal position. An electric motor drives an anvil to compress a tablet at a constant rate. The tablet is pushed against a stationary anvil until it fractures. A reading is taken from a scale indicator.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a></li>
<li>Kraemer Elektronik's tablet testing system was the first automatic tablet hardness testing system for auto-regulation at tablet presses, invented by German mechanical engineer Mr. Norbert Kraemer in Darmstadt, Germany. The tablets are separated by a patented feeder chute and moved on a horizontal starwheel through different testing stations. The Kraemer Elektronik automatic tablet testing system measures weight, thickness, diameter/length, width and hardness of tablets and capsules.<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a></li></ul>
<h2 id="units-of-measurement">Units of measurement</h2>
According to the <a href="/facts/International_System_of_Units/S7YLglNz">International System of Units</a>, the <a href="/facts/Units_of_measurement/pvTpWbmC">units of measurement</a> of tablet hardness mostly follow standards used in materials testing.

<ul><li>Kilogram (kg) – The kilogram is recognized by the SI system as the primary unit of mass.</li>
<li>Newton (N) – The Newton is the SI unit of force; the standard for tablet hardness testing. 9.807 Newtons = 1 kilogram (at one G, earth surface gravity).</li>
<li>Pound (lb) – Technically a unit of force but can also be used for mass under earth gravity. Sometimes used for tablet strength testing in North America, but it is not an SI unit. 1 kilogram = 2.204 pounds.</li>
<li>Kilopond (kp) – Not to be confused with a pound. A unit of force also called a kilogram of force. Still used today in some applications, but not recognized by the SI system. 1 kilopond = 1 kgf.</li>
<li>Strong-Cobb (SC) – An <a href="/facts/Ad_hoc/IYxx5Ha8">ad hoc</a> unit of force which is a legacy of one of the first tablet hardness testing machines.<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a> Although the SC is arbitrary, it was recognized as the international standard from the 1950s to the 1980s. 1 Strong-Cobb represented roughly 0.7 kilogram of force or about 7 <a href="/facts/Newton_(unit)/Ral9XgNl">newtons</a>.<a class="footnote-ref" id="fnref:21" href="#fn:21">21</a> Although the Strong-Cobb unit is arbitrarily based on the dial reading of the Strong Cobb hardness tester, it became an international standard for tablet hardness in the 1950s until it was superseded by testers using SI units in the 1980s.<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a> The Strong-Cobb is a unit with a very unusual name for a unit of measurement since it is named after the company, Strong-Cobb Inc. The inventor of the hardness tester was Robert Albrecht,<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> the plant engineer for the Strong-Cobb Company. He sold the patent to the company for $1.00.</li></ul>
<h2 id="sources">Sources</h2>

<h2 id="further-reading">Further reading</h2>
<ul><li>J. E. Rees & P. J. Rue (1978). <a href="https://www.researchgate.net/publication/232079217">"Work Required to Cause Failure of Tablets in Diametral Compression"</a>. Drug Development & Industrial Pharmacy. 4 (2): 131–156. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.3109%2F03639047809055644">10.3109/03639047809055644</a>. Retrieved 16 February 2013.</li>
<li>American Society for the Testing of Materials (ASTM), Designation: E4–07, '<a href="http://www.astm.org/Standards/E4.htm">Standard Practices for Force Verification of Testing Machines</a>'.</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Joseph Price Remington (2006). Remington: The Science And Practice Of Pharmacy. Lippincott Williams & Wilkins. ISBN 0781746736. <a href="0781746736" target="_blank">0781746736</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">"Tablet hardness testing". Sotax. Archived from the original on 5 January 2013. Retrieved 16 February 2013. <a href="https://web.archive.org/web/20130105054718/http://www.sotax.com/Hardness.116.0.html" target="_blank">https://web.archive.org/web/20130105054718/http://www.sotax.com/Hardness.116.0.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Joseph Price Remington (2006). Remington: The Science And Practice Of Pharmacy. Lippincott Williams & Wilkins. ISBN 0781746736. <a href="0781746736" target="_blank">0781746736</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">US 2645936, Robert, Albrecht, "Tablet hardness testing machine", published 1953-07-21, assigned to Strong Cobb & Company Inc.
 <a href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936" target="_blank">https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">"Tablet hardness testing". Sotax. Archived from the original on 5 January 2013. Retrieved 16 February 2013. <a href="https://web.archive.org/web/20130105054718/http://www.sotax.com/Hardness.116.0.html" target="_blank">https://web.archive.org/web/20130105054718/http://www.sotax.com/Hardness.116.0.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">"Some Information on Tablet Hardness Testing". Engineering Systems. Retrieved 16 February 2013. <a href="http://www.engsys.co.uk/pages/testing.php" target="_blank">http://www.engsys.co.uk/pages/testing.php</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Joseph Price Remington (2006). Remington: The Science And Practice Of Pharmacy. Lippincott Williams & Wilkins. ISBN 0781746736. <a href="0781746736" target="_blank">0781746736</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"Quality control of solid dosage form". Scribd. Retrieved 16 February 2013. <a href="https://www.scribd.com/doc/6766629/QCtablet" target="_blank">https://www.scribd.com/doc/6766629/QCtablet</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">"Quality control of solid dosage form". Scribd. Retrieved 16 February 2013. <a href="https://www.scribd.com/doc/6766629/QCtablet" target="_blank">https://www.scribd.com/doc/6766629/QCtablet</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">McCallum, A.; Buchter, J.; Albrecht, R. (1955). "Comparison and correlation of the Strong Cobb and the Monsanto tablet hardness testers". Journal of the American Pharmaceutical Association. 44 (2): 83–85. doi:10.1002/jps.3030440208. PMID 14353719. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">"Quality control of solid dosage form". Scribd. Retrieved 16 February 2013. <a href="https://www.scribd.com/doc/6766629/QCtablet" target="_blank">https://www.scribd.com/doc/6766629/QCtablet</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">"Quality control of solid dosage form". Scribd. Retrieved 16 February 2013. <a href="https://www.scribd.com/doc/6766629/QCtablet" target="_blank">https://www.scribd.com/doc/6766629/QCtablet</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">"Quality control of solid dosage form". Scribd. Retrieved 16 February 2013. <a href="https://www.scribd.com/doc/6766629/QCtablet" target="_blank">https://www.scribd.com/doc/6766629/QCtablet</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Charles, Ischi AG (2017). "Automated tablet & capsule testing technology". Scribd. <a href="https://www.ischi.ch/ipc-line/uts4-1-universal-tablet-testing-system/" target="_blank">https://www.ischi.ch/ipc-line/uts4-1-universal-tablet-testing-system/</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">US 2645936, Robert, Albrecht, "Tablet hardness testing machine", published 1953-07-21, assigned to Strong Cobb & Company Inc.
 <a href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936" target="_blank">https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Russ Rowlett (September 1, 2004). "How Many? A Dictionary of Units of Measurement". University of North Carolina. Retrieved 16 February 2013. <a href="http://www.unc.edu/~rowlett/units/dictS.html" target="_blank">http://www.unc.edu/~rowlett/units/dictS.html</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">McCallum, A.; Buchter, J.; Albrecht, R. (1955). "Comparison and correlation of the Strong Cobb and the Monsanto tablet hardness testers". Journal of the American Pharmaceutical Association. 44 (2): 83–85. doi:10.1002/jps.3030440208. PMID 14353719. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">US 2645936, Robert, Albrecht, "Tablet hardness testing machine", published 1953-07-21, assigned to Strong Cobb & Company Inc.
 <a href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936" target="_blank">https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2645936</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
</ol>

Tablet hardness testing open-in-new

Tablet hardness testing