Microbeads: a novel multiparticulate drug delivery technology for increasing the solubility and dissolution of celecoxib.

The purpose of this study was to develop a novel multipaticulate drug delivery technology suitable for the delivery of pre-solubilized celecoxib to the gastrointestinal tract and more specifically to the colon. The solubility of celecoxib in a range of oils, surfactants and co-solvents was evaluated. Celecoxib was solubilized in mixtures of these vehicles to produce liquid formulations. The in vitro dissolution of these liquid formulations was assessed and the data obtained was used to design microbead formulations containing celecoxib dissolved within an emulsion/micellar solution core. Microbead formulations were optimized to increase drug loading, avoid precipitation and to achieve good in vitro dissolution performance. An optimized formulation with a celecoxib loading of 6% w/w was produced and yielded an in vitro dissolution result of 80% over 6 h. The structure of these microbead formulations was characterized using light microscopy to reveal a correlation between droplet size and dissolution performance.

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

OBJECTIVES: 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. METHODS: 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. KEY FINDINGS: 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. CONCLUSIONS: 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.

Excipient-free nanoporous microparticles of budesonide for pulmonary delivery.

The aim of this study was to investigate the application of a spray-drying process for the production of nanoporous microparticles (NPMPs) to budesonide, and to characterise the particles produced in terms of their suitability for pulmonary delivery. Budesonide was spray dried with and without ammonium carbonate from ethanol/water or methanol/water solutions. The solid-state characteristics and micromeritic (particle size, density, surface area) properties of spray dried powders were assessed. In vitro deposition studies were performed to assess aerosol performance. The densities of the NPMPs were significantly lower and the surface areas significantly higher than for non-porous spray dried or micronised material. NPMPs of budesonide demonstrated improved aerosolisation properties compared to spray dried non-porous, micronised material and two budesonide commercial products. All spray dried materials were amorphous in nature. The glass transition temperature (approximately 90 degrees C) was sufficiently high to suggest good physical stability at room temperature. When stored at 25 degrees C/60% RH NPMPs showed a reduced tendency to recrystallise compared to the equivalent non-porous spray dried powder. The physical stability and amorphous nature of NPMPs was retained, under these storage conditions for at least one year and the in vitro aerosolisation properties were not affected by the storage conditions. Excipient-free porous microparticles, prepared by the novel process described, show good potential for drug delivery by oral inhalation with improved in vitro deposition properties compared to non-porous particles.