Combination of inulin and time dependent polymethacrylates as a coating system to achieve colonic delivery of indomethacin

In the previous study it was shown that films prepared from inulin (In) in combination with Eudragit RS (ERS) and RL (ERL) were susceptible to inulinase. Purpose: The aim of this work was to assess the suitability of these combinations for colonic delivery of indomethacin.Methods: Indomethacin was loaded onto non-pareil seeds using fluidized bed apparatus to produce pellets with 20% w/w drug load. Drug loaded pellets were coated with In-ERS in the ratios of 20:80 and 30:70, or In-ERL in the ratio of 20:80 to different coating loads. The release of drug was examined in simulated gastric (for 2 hrs) and small intestine and in the presence of inulinase in simulated colonic medium (for 12 or 24 hrs). Results: The results of this study revealed that incorporation of inulin as a bacterially degradable polysaccharide into ERS or ERL could modulate drug release. Coating level up to 15% significantly affected drug release from In-ERL or In-ERS coated pellets. However further increase in coating load to 20% had no significant effect on drug release from In-ERL coated pellets (f1=9.39). Drug release from In-ERL coated pellets was faster and showed some pH dependency. Conclusions: Formulation coated with In-ERS (20:80) and coating level of 20% was considered more appropriate for colon delivery of indomethacin, as drug release was pH independent and formulation was resistant to drug release in the upper GI media for up to 7 hrs. This formulation was also susceptible to inulinase and released about 40% of indomethacin in the simulated colonic media