In-vitro characterisation of a novel celecoxib microbead formulation for the treatment and prevention of colorectal cancer.

Abstract

Colorectal cancer (CRC) is a life-threatening disease that can develop as a consequence of a sustained chronic inflammatory pathology of the colon. Although not devoid of side effects, the anti-inflammatory drug celecoxib (CLX) has been shown to exert protective effects in CRC therapy. The purpose of this study was to develop and characterise a novel CLX microbead formulation suitable for use in the treatment and prevention of CRC, which has the potential to minimise the side effects associated with CLX. The study involved the assessment of the effectiveness of CLX formulations in an in-vitro cell model (HT29 cells) and a comparison of these effects to that of the marketed CLX product, Celebrex. Liquid CLX formulations were developed as precursors to microbead formulations. The effect of liquid CLX formulations on HT29 cell viability (MTT and flow cytometry apoptotic assays) and motility (scratch wound assay) were assessed and compared with the effect of Celebrex. A correlation between the in-vitro dissolution performance of the formulations and the effect in the cell model was also explored. Liquid CLX formulations were translated into an optimised CLX microbead formulation, and a colonic targeted sustained release coat (Surelease) was applied to the beads with the aim of producing a formulation for a future in-vivo study to compare the effect of the coated CLX microbeads versus Celebrex in the attenuation of CRC tumours and inflammation in a CRC murine model. The production of CLX microbeads was scaled-up using vibrating-jet encapsulation technology to allow for the development of an optimised dissolution profile to enable colonic release. In-vitro cell viability and motility were shown to be significantly reduced after treatment with CLX liquid formulations relative to the control, whereas the results for treatment with Celebrex were comparable with the control. Dissolution experiments and correlation analysis demonstrated that the formulations that showed a greater extent of drug release had reduced cell viability and motility. The CLX liquid formulations were translated into colon-targeted CLX microbeads suitable for use in a future in-vivo mouse study. These results represent a significant step forward in the chemopreventative treatment of CRC using CLX, as the microbead formulation developed suggests the possibility of presenting CLX in a format that has the potential to minimise gastrointestinal and cardiovascular side effects.