Using hybridoma technology, we generated and characterized a specific monoclonal antibody against recombinant human RANK receptor, and chemically coupled synthetic sCT to that anti-RANK mAb carrier. We further PEGylated sCT in the process of conjugation by using the polymer polyethylene glycol, which is known to improve the major disadvantages of conventional sCT by increasing solubility, stability, and efficacy and reducing the immunogenecity. It has also been established that PEGylation enhances the enzymatic stability of calcitonin (29) against proteolysis, by forming an effective shield against degradative enzymes (30) whilst improving its efficacy in vivo by increasing molecular size, thus contributing to reduced renal filtration (31) allowing less frequent administration (32) .