Abstract

Objective: To develop colon targeted tamoxifen tablets employing interpolymer complexes (IPC) between carboxymethyl fenugreek gum (CMF) and chitosan (CH) or carboxymethyl guar gum (CMG) and CH. Methods: IPC between CMF and CH or CMG or CH was obtained as a result of reaction between negatively charged -COO- group of CMF or CMG and positively charged -NH3+ group of CH. These interactions were characterized by FTIR spectroscopy. The core tablets were coated with various ratios of CMF:CH and CMG:CH IPC solutions. The coated tablets were subjected to in vitro dissolution studies in the presence or absence rat cecal contents. The selected coated tablets were evaluated for their pharmacokinetic behavior by oral administration to rats. Results: The tablets coated with CMF:CH 40:60 and CMG:CH 50:50 were capable of protecting drug release in pH 1.2 (stomach) and pH 7.4 (small intestine) and releasing, respectively, 91% and 94% tamoxifen in pH 6.8 in the presence of rat cecal contents. The oral administration of these tablets to rats showed a tmax of 10 hrs as compared to 2 hrs in case of uncoated tablets. Conclusions: The tablets coated with CMF-CH ratio of 40:60 or CMG-CH ratio of 50:50 were able to protect drug release in stomach and small intestine and deliver tamoxifen after the tablets reached colon.

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