Formulation and Anticancer Efficacy Evaluation of Polymeric and Cyclodextrin Nanocapsules Designed for Oral Application

Abstract

The objective of this thesis was to design and in vitro-in vivo evaluate oral nanocapsules prepared from amphiphilic cyclodextrins (CD) or poly-ε-caprolactone (PCL) with anionic or cationic surface charge for the effective oral delivery of an anticancer agent, Camptothecin (CPT). CPT loaded anionic and cationic nanocapsules coated with Chitosan (CS) were prepared by nanoprecipitation method and characterized in terms of mean particle size, polydispersity index and zeta potential. Morphological analysis of nanocapsules was performed by Scanning Electron Microscope (SEM). The percentage of CPT incorporated in nanocapsules was measured by a previously validated HPLC method. In vitro release of CPT from nanocapsules was evaluated using dialysis method under sink conditions. To determine the protective effect and drug stability provided by nanocapsules, all the formulations were incubated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Furthermore, CPT stability when incorporated in nanocapsules was determined with a validated HPLC method in phosphate buffer solutions (PBS) with different pH values of 1.2, 6.8 and 7.4 representing the pH range of the GI tract. In order to investigate mucin-particle interactions, measurement of mucoadhesive tendency of CPT loaded nanocapsules was realized by turbidimetric method. The interaction between mucin and particles were also evaluated in terms of mean particle size, polydispersity index and zeta potential values in the presence of mucin or not. Penetration of nanocapsules through an artificial mucus model was performed according to an artificial mucus model. Cytotoxicity of blank nanocapsules were investigated in L929 cell line. The permeability of CPT in solution form and bound to nanocapsule formulations were demonstrated across Caco-2 cell line. Anticancer efficacy of CPT loaded nanocapsules was determined against MCF-7 cell line in comparison to CPT solution. Finally, the intestinal uptake of nanocapsules was evaluated in vivo, in a mouse model with oral gavage in female CD1 mice. Both anionic and cationic CPT loaded CD and PCL nanocapsules were in the range of 180 to 220nm with a narrow size distribution and desired zeta potential values. CPT loaded nanocapsules were found to be stable in simulated gastrointestinal media. Turbidimetric measurements confirmed the interaction between nanoparticles and mucin. Penetration of CPT through an artificial mucus gel layer was higher when incorporated in CD nanocapsules than PCL nanocapsules, coating with cationic polymer Chitosan further increased penetration. Permeation of CPT across Caco-2 cell line was found to be higher when incorporated in nanocapsules than CPT solution in DMSO. In vivo animal studies confirmed that the intestinal uptake of nanocapsules was significantly higher with cationic nanocapsules. Both in vitro and in vivo results suggested that CPT loaded positively charged CD nanocapsules might be an attractive and promising treatment to improve the stability and bioavailability of anticancer drug camptothecin and create a new platform for oral chemotherapy.