Papain Loaded Solid Lipid Nanoparticles for Colorectal Cancer Therapy

Background: Colorectal cancer (CRC) also known as bowl cancer is still one of the leading causes of cancer related mortality worldwide. Generally tumor cells are protecting themselves by fibrin coat and it is resistant to fibrinolytic degradation. Such a coated tumor appears as 'self' to the immune system, and thus is not detected as a tumor by the immune system (i.e. natural killer cells). Hence, a potent proteolytic enzyme has to propose/identify to dissolve the protective fibrin layer, exposing the tumor cell surface to chemotherapy and immune attack. In this research papain was considered to be the potential proteolytic agent, can break down the fibrin coat of cancer cell wall and ultimately the cancer cells are exposed to immune attack and help against the cancer. Secondly, the cytotoxic compound(s) directly deliver to cancer site without harm to normal cells. Methods: The attempt made to attain this objective, we were designed to fabricate the Papain loaded solid lipid nanoparticles (SLN) by melt dispersion-ultrasonication technique, and investigate the various formulation parameters. The papain loaded SLN was characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), Scanning electron microscopy (SEM), drug encapsulation efficiency, in vitro drug release, and in vitro cytotoxicity studies on HT-29 colorectal cancer cells. Results: The successful outcome of this research was that, the cetyl alcohol based SLN of papain were successfully prepared by using melt dispersion- ultrasonication method with maximum encapsulation efficiency with desired particle size. The release profile of the produced SLN was investigated in phosphate buffer media, and it showed prolonged release during 24 h. The drug release behaviour from the SLNs exhibited a biphasic pattern with the burst release at the initial stage and sustained release subsequently. Future perspective of this research is that need to investigate the SLN for the lymphatic uptake to produce local action on metastatic colorectal cancer. In vitro cell viability for P-SLNs was tested on colorectal Adenocarcinoma HT-29 cells by MTT assay. The results revealed that the in vitro cell viability against different concentrations of papain was 99% and 31 % which were treated with 5 mu g/ml and 80 mu g/ml concentration respectively. The cell viability of HT-29 cells was decreased signicantly from 94 % to 17 % treated with P-SLN at 5 mu g/ml and 80 mu g/ml concentration respectively. Therefore, the papain loaded SLNs exhibits a better performance on getting lower cell viability (or) equivalent high cytotoxicity than that of pure papain. Therefore, the SLNs delivery system plays a significant role in enhancing the cytotoxic efficacy of papain enzyme against colorectal cancer cells. Conclusion: In this research, we successfully formulated the P-SLN for the treatment of colorectal cancer therapy. We investigate the various formulation parameters, drug release profile and cytotoxic efficacy of P-SLN. Upon successful completion of this work, P-SLNs delivery system is predictable to produce enhanced cytotoxic efficacy against HT-29 colorectal cancer cells. The papain loaded SLNs can potentially be utilized as a drug delivery system for the treatment of colorectal cancer. In future, we will explore further to investigate the mechanism of anticancer activity and clinical investigation of P-SLN.