[adimed]

Substances that are capable of enhancing the response of the immune system to the antigen are termed as Adjuvants. They can also be substances that enhance the effect of a drug on the body. The history of Adjuvant can be traced back to 1920s, when French biologist, Gaston Ramon revealed that the response of antitoxins to tetanus and diphtheria was amplified by injection of these vaccines, along with other substances such as lecithin, agar, starch oil, saponin, and breadcrumbs. Adjuvants are mainly utilized in organisms that are used to raise antibodies by injecting the antigen. The net effect is to stimulate a larger and more prolonged generation of the antibody.

Adjuvants exercise their action in various ways. Some Adjuvants retain the antigen and so present the antigen to the immune system over a long period of time as the immune response does not occur all at the same time, but relatively is continuous over a longer period. An Adjuvant also by itself can react with some of the cells of the immune system and this interaction may fuel the immune cells for heightened reaction. Adjuvants can also increase the recognition and ingestion of the antigen by the phagocyte. This increased phagocytosis presents more antigens to the other cells that form the antibody.

Adjuvants are chemically greatly heterogeneous set of compounds having a common ability of enhancing the immune response. The Adjuvants such as aluminium phosphate, aluminium hydroxide and calcium phosphates are commonly utilized for human use. Other varieties of adjuvants include cholesterol, endotoxins, aliphatic amines, fatty acids, gram-negative bacteria or products derived from bacteria, liposomes and vegetable oils. In the recent years compounds such as SAFs (syntax adjuvant formulations consisting of muramyl dipeptide or threonyl derative), ISCOMs with Quil-A, and monophosphoryl lipid A are under evaluation for utilization in human vaccine.

Immunopotentiators or vaccine Adjuvants have gained plentiful consideration as important ingredients of vaccine for the current and future. At present times in most of the countries worldwide aluminium salts (alum) remains as the only approved adjuvant for human use with few exceptions.