A Biomolecule can be defined as any molecule generally formed by a living organism. It mainly includes macromolecules and micro molecules. The best example for large molecules are Proteins, Nucleic acids, Lipids and Polysaccharides and small molecules such as natural products, Primary and secondary metabolites. Biomolecules are also known as biogenic substances. Synthetic analogs are defined as the artificial compounds differing from the natural compounds in their structure, resemblance and function. Synthetic refers to any material made from non natural sources. This means that a product such as cloth is made from a chemical source rather than the fibers produced by nature. Biomolecules and their synthetic analogs play vital role in medicine, drug delivery or antiviral agents etc. Most analogues are designed because "true synthetic" natural products are hard to make, or are not potent enough. For instance, morphine is poorly absorbed and of only moderate potency, but if it is converted into hydromorphone or heroin (analogues) it gains potency and can be more completely absorbed (in the case of some morphine esters). However all the classical opiates are very hard to make in laboratories, so drugs like pethidine, methadone, abd fentanyl were devloped that are much easier to make and are not dependent on opium poppy production. In Pharmacology Analog is referred as Functional analog, and structural analog; A chemical compound with similar properties to another is a Functional analog. Structural analog is a chemical compound with a slightly altered chemical structure compared to another.