Development of digital gastrointestinal model and its application in absorption prediction of nifedipine sustained-release tablets

The purpose of this reaearch was to predict plasma concentration-time profiles of nifedipine (NFP) sustained-release formulation,and identify the critical parameters of absorption via sensitivity analysis.Firstly,digital gastrointestinal model (DIM) was established using VBA program and input parameters was obtained through the investigation of intestinal absorption characteristics of NFP from different intestinal regions,different pH and with or without excipients,providing guidance for the design of NFP sustained-release formulation.Results showed that the apparent permeability coefficients (P_app) of NFP was larger than 1.0 ×10^-6cm/s at intestinal and colon.Co-incubation with excipients could significantly influence the permeability of NFP.The pH of drug solution had little effect on the P_app of NFP.NFP is well absorbed at the whole intestine of rats.However,parameter sensitivity analysis showed that variation of the absorption rate had no distinct effect on the concentration-time profile of NFP.The dissolution rate and intestinal transit time were the critical parameters of NFP sustained-release formulation.In conclusion,DIM can provide guidance for the design of NFP sustained-release formulation.