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