Pharmacotherapy is the most appropriate approach for treating a disease and provide the treatment either symptomatic or definite for curing a disease. There are various routes of administration of a drug but the route which is most important and mostly used without any invasive procedure is oral route. But there are some drawbacks of this mostly used route as pre-systemic elimination of drug as well as the first pass hepatic effect of a drug. The most important feature of a drug to give its utmost benefit is its bioavailabiloity and which is also limited of some drugs given orally due to various factors affecting it like membrane permeability, pharmacokinetic features, solubility as well as the rate of dissolution. To overcome all these factors affecting the drug bioavailabulity some modifications are done to get the proper effect of drug like to increase solubility these drugs are prepared in nano formulation to provide the maximum concentration at the required site of action. One of these innovations in formulation of drugs is liposomes as to formulate the drugs in lipid based drug delivery. Liposomes are trifling synthetic vesicles which are spherical in shape that can be formed by the cholesterol in addition to natural but non-toxic phospholipids. Owed to their magnitude in addition to hydrophobic as well as hydrophilic oddity these liposomes are encouraging systems intended for drug delivery.

Keywords: Drugs, Bioavailability, Permeability, Phospholipids, Hydrophilic, Hydrophobic