Preparation and Characterization of Colon-Specific Microspheres of Diclofenac for Colorectal Cancer

Purpose: To prepare and evaluate colon specific drug delivery system of diclofenac sodium for highly localized delivery to the colon.
Methods: The colon specific drug delivery system was prepared as matrix-type microspheres using Ethyl Cellulose (EC), Cellulose Acetate Phthalate (CAP), and Eudragit L 100-55 by the Solvent Evaporation Method. Microspheres were evaluated for physical properties like drug content, particle size, bulk density and angle of repose.
Results: The size range of the microcapsules was 228 to 608 μm while drug content was between 74.49 and 91.50 % depending on the polymer used and the polymer ratio. Mean bulk density was < 1.2 g/ml which indicates the good flow properties, while angle of repose was < 40 °, indicating free-flowing properties. The microspheres were spherical in shape with smooth and nonporous surface, except that the microspheres containing EC and CAP exhibited a rough and porous surface. The microspheres containing Eudragit L 100-55 in combination with other polymers gave better sustained release (78.9 and 76.6 % at the end of 8 h for formulation F4 and F5, respectively) than the others.
Conclusion: Microspheres prepared with drug: EC: CAP ratio of 1:2:1 show the highest drug content, possess good flow properties and surface morphology, as well as promising drug release for colon specific drug delivery of diclofenac sodium for possible treatment of colorectal cancer.

Keywords
Diclofenac; Colorectal cancer; Microspheres; Ethyl cellulose; Cellulose acetate phthalate; Eudragit L 100-55