It was found that the produced nanoparticles with the glycyl phenylalanyl leucyl glycine tetra-peptide (GFLG) acting as a cleavable linker sensitive to enzymes are able to release the drug much faster in the tumor cellular environments, which contain explicitly secreted cathepsin B. It was presented that nearly 90% of GEM was released in the presence of the enzyme compared to the absence of cathepsin B. Such enzyme-sensitive systems provide benefits through their specific functions in biological and metabolic pathways [39]. Here, CTSB is linked to neoplasm.