ROLE OF WETTING ON RATE OF DRUG RELEASE FROM INERT MATRICES

This investigation has shown that matrix permeability and rates of permeation of the matrix by the solvent can individually limit drug release rates. This was found to be a function of the pore size distribution of the matrix and the permeation pressure of the release media defined by its surface tension and contact angle. Methods useful in separating the various roles of the above were developed and are presented. They include the correlation and use of external pressure, vacuum techniques, surface tension and contact angle measurements, and porosimeter data. The results have been used to develop models to illustrate the possible systems that can be encountered. Concepts such as rates of pore permeation, varying solubility dependence, and tortuosity are developed and applied to these models. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company