The present study was aimed at formulating
tablets comprising of coating susceptible to microbial
enzyme degradation for releasing
budesonide in the colon.
Tablets prepared by using
Avicel pH 102 as diluent and
Eudragit L100-55 as binder were coated to a
weight gain of 10% w/w employing aqueous mixtures containing
chitosan (CH) and
chondroitin sulfate (CS). The interpolymer complex between CH and CS was characterized using Fourier transform infrared (FTIR) and differential scanning calorimetery (DSC) studies. The
tablets were evaluated for release of
budesonide through in vitro in vivo studies. Formation of bonds between -
COO(-) and -OSO3(-) groups of CS and -NH3+ groups of CH was evident in the FTIR spectra of these interpolymer complexed (IPC) films. The DSC thermograms of these films revealed one endothermic transition between 190 degrees C and 205 degrees C, suggesting the formation of new bonds in the IPC. The pH sensitive swelling exhibited by these films was observed to be a function of CH concentration.
Tablets coated with aqueous mixtures containing 40:60 or 50:50 ratio of CH/CS totally prevented the release of
budesonide in pH 1.2
buffer. The peaks (FTIR) and endothermic transitions (DSC) characteristic of interpolymer complexation were observed to remain unaffected after sequential exposure of the films to pH 1.2 and pH 7.4
buffer IP. This proved the versatility of these IPC films for colon delivery. C (max) of 1,168.99 and 1,174.2 ng/mL, respectively, at 12 and 8 h post-oral dosing of
tablets coated with 40:60 or 50:50 ratio of CH/CS was observed in rats. The aqueous CH/CS (40:60) coating could provide a facile method for delivering
budesonide to the colon.