In this paper, we formulate a broad-based mathematical model for drug absorption in the intestine based on the peristaltic motion of the drug-carrying intestinal fluid which is approximately sinusoidal. Using the background of Fick’s laws and perturbation methods, an initial – boundary value problem is formulated and solved and the drug concentration, at a distance along the intestinal tract at time determined. In doing this, we use the result of drug absorption in the gastrointestinal tract for constant velocity of the intestinal fluid [14]. The solution is analyzed for various frequencies (or wave numbers) of the peristaltic wave for the drug indomethacin. The results do not show marked deviations for low frequencies; but for large frequencies, it has been observed that the absorption is more rapid. Thus, the results show that with higher peristaltic wave frequency, the drug particles that had diffused into intestinal fluid are more in contact with the villi surrounding the intestinal lumen and hence absorption is enhanced.

Keywords : Mathematical model, peristalsis, drug absorption, intestinal.