The power law can describe the 'entire' drug release curve from HPMC-based matrix tablets: a hypothesis

The purposes of this study were to (i) re-examine the relevance of Higuchi equation and the power la Using both simulated and experimental release data in conjunction with the linearized. in tern's of t(1/2). percent of drug release plots. (ii) demonstrate that the power law describes the entire drug release profile of several experimental data, and (iii) point out a physically based hypothesis for the Successful Use Of power law in describing the entire drug release profile. Simulated data generated from the equation of power law were further analyzed using linear regression analysis in accord with the Higuchi equation. The analysis revealed that data generated from the equation Of power law can be misinterpreted as obeying the Higuchi equation. The use of power law in describing the entire drug release curie from HPMC-based matrix tablets is validated by direct fit of power law equation to published data of other authors. A hypothesis based on the nonclassical diffusion of the solutes in the HPMC matrices is used to interpret the successful use of the power law in describing the entire release profile. (C) 2003 Elsevier Science B.V, All rights reserved.