Pharmacoscintigraphic assessment of mucoadhesive nanoparticles designed for colon-specific delivery

Colon-specific delivery of anti-inflammatory drugs is restricted due to numerous reasons such as premature release of the drugs and their enzymatic degradation in the upper gastrointestinal tract. Hence, various nano based drug delivery systems are being designed to overcome this. The primary objective of this research was to carry out a scintigraphic assessment of drug-loaded mucoadhesive microspheres for colonic delivery. The nano formulation was prepared by optimized concentrations of pectin, ethanol, ethyl acetate, and sodium alginate. This drug-loaded nano formulation was further characterized for their physiochemical characteristics, such as pH, particle size, and TEM studies, and further, for their in vitro studies including release kinetics and mucodhesive studies. The drug was subjected to pre labeling with ^99mTechnetium and further formulated into microspheres. The radiolabeled nanoparticles were then administered to the rabbits in capsule form and gamma scintigraphy was carried out at 1 h and 5 h post administration. The developed microspheres were found to be spherical in shape which was validated by TEM images. The in vitro studies suggested that the drug release from the formulation was slow and sustained over a period of 5 h. A significant higher drug release was observed in the colonic region in scintigraphic studies post administration of radiolabeled formulation. Further, the biodistribution studies also validated these findings. The study suggested that the developed formulation has tremendous potential for colonic delivery of drugs in conditions such as inflammatory bowel disease