ABSTRACT
The lymphatic system is considered an important route for drug targeting as drugs given through oral route are more effective. Drugs those can absorb from intestine into the systemic circulation possess reduced oral bioavailability due to the decomposition in the gastrointestinal tract before absorption. Usually, pH of stomach varies from 1.0 to 4.0. This highly acidic atmosphere may cause the decomposition of orally given drugs, and also before entering the blood, the drug absorbed into the portal venous system undergoes rst-pass metabolism in the liver, and as a result the bioavailability and plasma concentration of the drug lowers. However, highly lipophilic drugs will transfer through the enterocyte and combine with enterocyte lipoproteins to form chylomicrons (Charman and Stella 1986). The chylomicrons along with the drug enter the mesenteric lymph duct, move to the thoracic duct, and then enter the systemic circulation, thus the highly lipophilic drugs bypass hepatic rst-pass metabolism. Thus, the lower bioavailability of drugs can be enhanced with the help of the lymphatic system for absorption in the intestine bypassing rst-pass metabolism in the liver (Trevaskis et al. 2008).
