Recent Progress in Stimuli Responsive Intelligent Nano Scale Drug Delivery Systems: A special focus towards pH sensitive systems.

Abstract

Stimuli responsive nanocarriers are gaining much attention due to its versatile multifunctional activities including disease diagnosis and treatment. Recently, clinical applications of nano drug delivery systems for cancer treatment make a considerable challenge due to its limited cellular uptake, low bioavailability, poor targetability, stability issues, and unfavourable pharmacokinetics. To overcome these issues researchers are focussing on stimuli responsive systems. Nano carriers elicit its role through endogenous (pH, temperature, enzyme and redox) or exogenous (temperature, light, magnetic field, ultrasound) stimulus. These systems were designed to overcome the shortcomings such as non-specificity and toxicity associated with the conventional drug delivery systems. The pH variation between healthy cells and tumor microenvironment creates a platform towards the generation of pH sensitive nano delivery systems. Herein, we propose to present an overview of various internal and external stimuli responsive behavior based drug delivery systems. Herein the present review will focus specifically on the significance of various pH- responsive nanomaterials such as polymeric nanoparticles, nano micelles, inorganic based pH sensitive drug delivery carriers such as calcium phosphate nanoparticles, and carbon dots in cancer treatment. Moreover, this review elaborates the recent findings on pH based stimuli responsive drug delivery system with special emphasis towards our reported stimuli responsive systems for cancer treatment.