Comparison of in vitro and in vivo release characteristics of acetaminophen from gradient matrix systems

An effort was made to correlate the in vivo and in vitro release data of acetaminophen from two formulations of a recently developed controlled‐release system, the Gradient Matrix System (GMS‐1 and GMS‐2). The in vivo release curves, obtained by deconvolution of the plasma concentration time plots, showed a small inter‐subject variability. GMS‐1 with fastest in vitro release also showed fastest in vivo release. A good relationship was only found after time‐scaling of the release data.