Document Detail

The tabletting machine as an analytical instrument: qualification of the measurement devices for punch forces and validation of the calibration procedures.
MedLine Citation:
PMID:  9885312     Owner:  NLM     Status:  MEDLINE    
The quality of force measurement in an eccentric tabletting machine equipped with piezo-electric load washers mounted under pre-stress at the upper and lower punches, and the reliability of their calibration in situ and under working conditions were carefully investigated, since this tabletting machine is used as an 'analytical instrument' for the evaluation of the compression behaviour of pharmaceutical materials. For a quasistatic calibration procedure the repeatability under standard conditions and the robustness against variations in machine settings, installation conditions, equipment and handling were evaluated. Two differently constructed reference load cells equipped with strain gauges were used for the calibration of the upper punch sensor. The lower punch sensor was calibrated against the upper one. Except for a mechanical hysteresis, owing to uneven stress distribution over the piezo-electric sensors, the results of the quasistatic measurements are assessed to be satisfactory. In addition, dynamic calibrations were performed. One of the strain-gauged load cells was used in addition to two piezo-electric load washers installed without pre-stress. The dynamic behaviour of all the transducers used is deficient. While for the piezo-electric sensors a significant change in the slope of the calibration function with respect to the quasistatic behaviour was observed, for the strain-gauged load cell a pronounced hysteresis must be noted. Comparing the dynamic behaviour at different profiles of rates of force development generated by variations in machine speed and by maximum force setting, the variability in the sensitivity of the upper and lower punch piezo-electric load washers is comparatively small.
P M Belda; J B Mielck
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft für Pharmazeutische Verfahrenstechnik e.V     Volume:  46     ISSN:  0939-6411     ISO Abbreviation:  Eur J Pharm Biopharm     Publication Date:  1998 Nov 
Date Detail:
Created Date:  1999-04-01     Completed Date:  1999-04-01     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  9109778     Medline TA:  Eur J Pharm Biopharm     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  381-95     Citation Subset:  IM    
Copyright Information:
Copyright 1998 Elsevier Science B.V.
Department of Pharmaceutical Technology, University of Hamburg, Hamburg, Germany.
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MeSH Terms
Chemistry, Pharmaceutical / instrumentation*,  methods*
Compressive Strength
Reproducibility of Results
Sensitivity and Specificity
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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