In-vitro cellular uptake and transport study of 9-nitrocamptothecin PLGA nanoparticles across Caco-2 cell monolayer model

The uptake and transport of 9-nitrocamptothecin (9-NC), a potent anticancer agent, across Caco-2 cell monolayers was studied as a free and PLGA nanoparticle loaded drug. Different sizes (110 to 950 nm) of 9-nitrocamptothecin nanoparticles using poly (lactic-glycolic acid) were prepared by via the nanoprecipitation method. The transport of nanoparticles across the Caco-2 cell monolayer as a function of incubation time and concentration was evaluated for each different nanoparticle formulation. The amount of 9-NC transported from the apical to the basolateral side and the uptake of the drug into the cells was determined by HPLC. The uptake of intact nanoparticles into Caco-2 cells was visualized by confocal laser scanning microscopy using 6-coumarin as a fluorescent marker. The study demonstrated that Caco-2 cell uptake and transport of encapsulated 9-nitrocamptothecin is significantly affected by the diameter of the carrier and incubation time. In addition it was shown to be independent of concentration. The results indicated a significant accumulation of the drug in the cell membrane and an enhanced diffusion across the cell membrane. There was also a sustained release of characteristics pertaining to polymeric carriers that provided prolonged drug availability for absorptive cells.