Impact of gastrointestinal residence time of extended-release (ER) tablets on in vivo evaluation of ER tablets

Extended-release tablets (ER) of cevimeline hydrochloride were prepared and in vivo absorptions following oral administration to beagle dogs were investigated. These in vivo studies were conducted with or without taking into account the gastrointestinal (GI) residence time of the ER tablet. The GI residence time of the ER tablets was identified from the fecal excretion time of the ER tablets for individual dogs after administration. It was difficult to investigate the in vivo performance of the slow-release ER tablets without knowing the GI residence time of the tablets. On the other hand, by combining the drug plasma concentration profiles and the fecal excretion time of the tablet, it was possible to adequately determine whether the designed ER formulation is possible for once-daily dosing. These results suggested that this approach was useful for the estimation of the in vivo performance of ER tablets.