Predicting the tensile strength of compacted multi-component mixtures of pharmaceutical powders.
OBJECTIVE
Pharmaceutical tablets are generally produced by compacting a mixture of several ingredients, including active drugs and excipients. It is of practical importance if the properties of such tablets can be predicted on the basis of the ones for constituent components. The purpose of this work is to develop a theoretical model which can predict the tensile strength of compacted multi-component pharmaceutical mixtures.


METHODS
The model was derived on the basis of the Ryshkewitch-Duckworth equation that was originally proposed for porous materials. The required input parameters for the model are the relative density or solid fraction (ratio of the volume of solid materials to the total volume of the tablets) of the multi-component tablets and parameters associated with the constituent single-component powders, which are readily accessible. The tensile strength of tablets made of various powder blends at different relative density was also measured using diametrical compression.


RESULTS
It has been shown that the tensile strength of the multi-component powder compacts is primarily a function of the solid fraction. Excellent agreement between prediction and experimental data for tablets of binary, ternary and four-component blends of some widely used pharmaceutical excipients was obtained.


CONCLUSIONS
It has been demonstrated that the proposed model can well predict the tensile strength of multi-component pharmaceutical tablets. Thus, the model will be a useful design tool for formulation engineers in the pharmaceutical industry.
Wu
Chuan-Yu
CY
Pfizer Institute for Pharmaceutical Materials Science, Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, UK. C.Y.Wu@bham.ac.uk
Best
Serena M
SM
Bentham
A Craig
AC
Hancock
Bruno C
BC
Bonfield
William
W
D000465:Algorithms; D002626:Chemistry, Pharmaceutical; D004338:Drug Combinations; D004339:Drug Compounding; D005079:Excipients; D008956:Models, Chemical; D010316:Particle Size; D016062:Porosity; D011208:Powders / Q000737:chemistry*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013607:Tablets; D013718:Tensile Strength
D004338:Drug Combinations; D005079:Excipients; D011208:Powders; D013607:Tablets