Gastric Emptying of Pellets under Fasting Conditions: A Mathematical Model

Purpose To develop a mathematical model that would adequately describe human gastric emptying of pellets under fasting conditions of healthy subjects. Methods Scintigraphic profiles representing the gastric emptying of pellets were obtained from the literature. Altogether 19 individual and three mean scintigraphic profiles were collected. Three mathematical models namely; the lag-time exponential (two parameters), the Weibull (two parameters), and the double Weibull (five parameters) model were proposed and fitted to the gastric emptying profiles. Results Different patterns of gastric emptying (immediate and rapid, delayed but rapid, delayed and slow, and interruptive emptying) were observed, with the emptying time varied from approximately 15 min to more than 3 h. The best model for fitting to the individual profiles was the double Weibull model. This model also provided an insight into the mechanism of interruptive emptying of pellets, observed for some patients. In addition, mean gastric emptying of pellets was calculated using the Weibull model. Conclusions Mean gastric emptying of pellets was adequately described by the Weibull model (η = 61.9 min, β = 0.895), which could be applied in the design of in vitro dissolution experiments for pellet formulations with pH dependent dissolution.