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Huxley Bertram Compaction Test Features
Huxley Bertram Powder Compaction Simulators are highly versatile machines that allow almost every imaginable powder formulation and tablet test to be carried out on a single platform. A fully configurable working space and versatile software help the development of new and existing testing methods.
Their testing versatility can be further extended with a range of test options, fitments and accessories to solve particular development and production problems in a material sparing and time efficient manner. These test options are summarised below.
Temperature Controlled Tooling
Repeated compaction in a tablet press can lead to high temperatures at the die wall, and a warming up through the batch as the press turret and tooling heat up. This can lead to temperature related problems such transformation, sticking, lubricant effects, or dissolution changes that remain undiscovered until late in the development cycle. Project risk can be greatly reduced by studying the effects of temperature on the compaction process, with temperature and strain rate effects studied in tandem.
Huxley Bertram temperature controlled tooling can simulate the real temperatures experienced during production, with controls integrated into the machine test software so that temperature data is automatically recorded. Production tooling may be modified for different applications with dies and punches controlled to different values. Boundary temperatures for acceptable quality tablets can be explored, and critically with representative production strain rates.
Tablets may fail due to the stresses created during ejection, either due to friction or shear when exiting the die. A solution for most materials is to release the die wall pressure after compaction, but before ejection.
The Manual Split Die Holder is an economical method of releasing die wall stresses after compaction, and producing compacts for further testing with dies split into, three or five sections that fit into the same space as a normal die.
Alternatively, a hydraulically actuated “split die” can be used, allowing radial die wall pressure to be automatically released before ejection. A further option is to use tri-axial pressure release servo control to release pressure in proportion to the axial punch pressure.
Hiestand Tri-Axial Fixture
Hiestand testing of compressed powders requires a homogenous cubic tablet with no stress cracks. Ideally a large compact is required, but for material sparing requirements, small sizes are also used. To produce compacts free of stress cracks, tri-axial decompression is required.
The Hiestand fixture and the tri-axial control option together allow Hiestand compacts to be produced on the Huxley Bertram Compaction Simulator. If the “High Force” actuator option is chosen, then the larger size compacts can also be made.
The lower punch holds a retractable probe, which allows compacts to be made with or without a central through hole. The system features easy change-over die faces and punches and programmable pressure ratios.
To meet the increasing popularity of cored or “dry encapsulated” tablets, Huxley Bertram offer the option of a “core feeder” to be placed on an existing hopper drive, with additional guides to ensure accurate core placement. Programming is simple and similar to a 3 layer tablet.
Core-rod tooling is used for a number of advanced tablet designs. It can be used to make simple rings or encapsulated segments or complex dissolution profiles. Both upper and lower punches can be made with individually actuated sleeves and core sections to achieve many complex tablet designs.
Roller Compaction Simulation Tooling
Study of behavior of formulations under roller compaction conditions. As a material sparing development option that is more convenient with the appropriate tooling and machine options, consisting of large rectangular punches and dies, typically in “D” format, with respective take-off shoe. Huxley Bertram software provides automatically loaded roller compaction test profiles.
Weight Thickness and Breaking
Huxley Bertram HB100 compaction simulators incorporate automatic weight, thickness and breaking measurement on machine to free up valuable laboratory time and ensure that more data is correctly and securely recorded. This feature is particularly valuable where tablets contain highly active pharmaceutical ingredients and need to be handled under isolation.
Development and study of capsule filling, a regular requirement during early stage drug development, can be performed faster and more economically with a fully programmable versatile machine. Capsule filling simulation can be achieved with low-force accessories on Huxley Bertram compaction simulators HB50 and upwards.
Both tamping disc and dosator methods can be studied for suitability, with comprehensive data recording of all aspects of the process for future study and reference.
Huxley Bertram offer different levels of operator protection from powders used in the machine that can be specified according to customer lab practices and levels of compound potency, ranging from simple vacuuming of the die table between tablets, through continuous air extraction and on to full containment with machine operation via glove-ports.
Simple removable tooling holders and an accessible uncluttered working area make for a quick clean down routine between projects. Powder and compact handling can be further reduced by automated weight, thickness and breaking measurements inside the enclosure.
Powder feeders may be charged on or off the machine, while capsuling development and micro-tablet fixtures can be used inside the containment enclosure.
Huxley Bertram will normally provide an annual calibration service if requested, usually at the same time as a machine service is performed. HB can supply a calibration kit to suit individual machine configuration.
The kit can include certified weights with fixtures for applying small loads, gauges for checking displacement measurement, calibration load cells and readout, plus storage and transport case.