Liver is one of the vital organ that performs many functions in the human body. Prominently it acts as a metabolizing organ for the body. This chapter elaborately describes hepatocytes along with their morphological features. In addition, it explains the structure of hepatocytes and different parts such as kupffer cells, hepatic stellate and hepatic sinusoids. Moreover present chapter elaborates the varieties of functions that hepatocytes perform such as filtration of blood, acting as a viral incubator, lipophagy and regulation of insulin and glucose. This chapter also explains hepatic injury that is caused by chronic consumption of alcohol along with the mechanism behind it.

Therapy of many ailments such as malignancy hepatitis, AIDS, cardiovascular diseases are carried out by using biological macromolecular drugs such as fusion protein drugs and antibodies. The majority of macromolecular drugs are either proteins or peptides, which are made into solution or suspension and are administered through intravenous or subcutaneous route that are invasive and painful. A significant level of attention has been given to oral macromolecular drug delivery over the last 30 years. The major obstruction faced by macromolecular drugs administered through oral route is the physical and biochemical properties of the epithelial layer of the gastrointestinal tract, which acts as a boundary. The chapter focuses on the physiological hindrance faced by protein and peptide during their conveyance through the GIT. Moreover, discussion about techniques that are used for dodging the boundaries and for enhancing the penetration of drug through GIT have been done. These methodologies can be of great value for absorption of drugs like bio macromolecules through the intestines.