The aim of the present work was to prepare the colon-targeting pH dependent microcapsules of Nigella sativa extract for the treatment of colorectal cancer. In this study, colon targeted microcapsules of Nigella sativa extract was formulated successfully using pH dependent polymers Eudragit L100, S100 using solvent evaporation method (method 1 and method 2). Microcapsules were evaluated for flow properties, surface morphology by scanning electron microscopy, percentage yield, drug content, and in vitro drug release behaviour and in vivo targeting efficiency. The good flowability and packability of microcapsules, indicates that they can be successfully handled and either filled into a capsule or compressed into tablet dosage form. The scanning electron microscopy of the microcapsules (5 ?m) revealed that they are spherical. N. sativa extract loaded microcapsules demonstrated good entrapment efficiency (of 83.159% in method 1 and 93.09% in method 2). The drug release study revealed that the microcapsules were capable to retard the drug release of drug up to 4 hours and efficiently released in colon (85.69%). Formulation done by method 2 gave most promising result compared to first method. So, the in vivo colon targeting efficiency of the formulation was done with microcapsules prepared by method 2. Determination of the in vivo targeting efficiency concluded that the formulation is able to target colonic region effectively. It is concluded from the present study that pH dependent Eudragit microcapsules are promising carriers for oral colon-targeted delivery of N. sativa extract for colorectal cancer.
