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In recent years, the nature incidence of Hepatitis C virus (HCV) infection was estimated as 3.2% in china.Platycodon grandiflorum A.DC, commonly known as Chinese drug Jiegeng, is widely used as a traditional oriental medicine.Novel researches indicated that extracts from the roots of P.grandiflorum have the protective effects on liver which have an inhibitory activity of HCV RNA polymerase NS5B and a very strong synergy with interferon.Meanwhile, Jiegeng has an irritating effect on gastric mucosa, causing light nausea and vomit after ordinary oral administration.The objective of this study was to develop control release pellets containing Platycodin D (PD) extracts and further evaluate their gastrointestinal mucosa irritations and pharmacokinetic profiles.PD extracts-loaded cores (drug loading about 50%, w/w) were prepared by extrusion-spheronization method and then coated with suspensions including enteric materials such as Eudragit(R) L100-55 or Eudragit(R) S 100 polymer in a fluid bed coater of the bottom spray type.The coated pellets with suitable coating level had a spherical form and a suitable acid resistance (Fig.l).The in vivo gastrointestinal mucosa irritations of different formulated PE pellets were then evaluated by HE staining and quantity of nuclear factor Kappa B (NF-κB).The enteric-coated pellets and colon specific pellets aroused less even invisible pathological changes of gastrointestinal mucosa than uncoated pellets.The concentration of NF-κB in stomach of the rats given uncoated-pellets was about 5 times of that given enteric-coated pellets and colon specific pellets (Fig.3 and Fig.4).Further more, pharmacokinetic studies in SD rats after oral administration of PE pellets of different dosage forms showed that the enteric-coated pellets had a similar pharmacokinetic process with uncoated pellets while the colon specific pellets had less bioavailability (Fig.2).Concerned about both gastrointestinal mucosa irritations and pharmacokinetic properties of PE pellets, the enteric-coated pellets could be a better choice.