Tableting operation automation

Special dedicated hardness testers or multifunctional systems are used to measure the degree of force (in kilograms, pounds, or arbitrary units) required to break a tablet. Devices to test tablet hardness include the Monsanto tester, the Strong-Cobb tester, the Pfizer tester, the Erweka tester, and the Schleuniger tester. A force of about 4 kg is considered the minimum requirement for a satisfactory tablet. Multifunctional automated equipment can determine tablet weight, hardness, thickness, and diameter. Unfortunately, these testers do not produce uniform results for the same tablet due to operator variation, lack of calibration, spring fatigue, and manufacturer variation. 

Tablet weight uniformity will provide a measure of the efficiency of the powder flow, tlie force feeder, or the automated weight control system. Weight monitoring by the press operator is usually the weight of a 5- or 10-tablet sample. Uniformity of individual tablets, which after all does relate to dose, will be more informative. The powder flow may not be sufficiently good, even with forced feeders.

The automation of the HPLC determination of tablet content uniformity has been applied to the analysis of a variety of tablets and is used routinely for quality control purposes. The routine used is fairly typical of that described by other workers, in that the operator presents the samples to the robotic system in tubes. The system then continues the analysis as follows ... 

A slightly more complex HPLC analysis of oral contraceptive tablets for content uniformity has been described [65]. The analysis was automated because it represented a high proportion of the laboratory workload, it was relatively routine, and it would reduce contact with steroids, therefore minimizing health risks. The last point was emphasized by placing the robotic system in a room separate from the main laboratory, with the controller outside the room. This is significantly different from the approach followed by many users of laboratory robotics, who often place the system in a main laboratory area. The robotic system performs the following steps, after the operator places the tablets into tubes in racks located on the robot table ... 

Schwartz, J.B. The instrumented tablet press uses in research and production. In Automation of Pharmaceutical Operations Fraud, D.J., Ed. Pharmaceutical Technology Publications Springfield, OR, 1983 229-239. 

A rotating enzyme-immobilized reactor and a flat pH electrode were incorporated into a sealed cell for use under continuous-flow/stopped-flow (SF) operation for the rapid determination of penicillins G and V in tablets and injectables [50]. A co-immobilization in a rotating bioreactor and amperometric detector resulted in a sensitive system for determination of succinylcholine and acetylcholine in pharmaceutical preparations [51]. A tandem system incorporating two rotating bioreactors into a continuous-flow/SF sample/reagentprocessing setup was apphed for the determination of alkaline phosphatase activity in serum samples [52]. By functional combination of the SF and flow-injection analysis (FIA), an automated micro apparatus was constructed resulting in significant reduction of the injection volumes of enzyme and substrate [53]. SF/continuous flow methods were apphed to acquire kinetic information also [54, 55]. 

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