Herbal and polymeric approaches for liver-targeting drug delivery: novel strategies and their significance

The liver is a vital organ present in vertebrates, which performs many functions including detoxification, protein synthesis and production of various bio-chemicals which are very important for digestion. A large number of serious liver disorders affect millions of people worldwide which are very difficult to treat properly despite many efforts. There are several factors which are responsible for liver injuries, include plants (Crotalaria Senecio Heliotropium Symphytum officinale), drugs (analgesic and antibiotics), industrial toxins (mercury and lead), water, alcohol and so on. Herbal medicinal preparations can be used for the treatment of a large number of human liver disorders like cirrhosis, hepatitis, carcinomas, etc. Indian Medicinal Practitioner's Co-operative pharmacy and Stores (IMPCPS) approved herbal-based systems (Unani, Siddha and Ayurveda) for the treatment of various chronic liver disorders. Different types of the receptors are found on the surface of hepatocytes, Kupffer cell, hepatic stellate cell and sinusoidal endothelial cells, etc., which can be used for achieving liver targeting. These receptors bind to different types of ligands (galactosylated, lactobionic acid, asialofetuin, etc.) which can be used in the formulation to achieve targeted delivery of the drug. Various novel particulate approaches (liposomes, niosomes, nanoparticles, micelles, nanosuspensions, etc.) can be used to enhance the targeting efficiency of systems to receptors found on the surface of different cells present in the liver. In this review, we focused on the status of liver targeting via herbal and nanotechnology inspired formulation approaches.