Pseudoatoms

  Bioisosteres are atoms or group of molecules that fit the broadest definition for isosteres. They have chemical and physical similarities thus producing broadly similar biological properties. Many heterocycles, when appropriately substituted exhibits bioisosterism. Bioisosterism represents an approach used by the medicinal chemist for the rational modification of lead compounds into safer and more clinically effective agents. It has significant value in drug design and lead optimization process as it may enhance the desired biological or physical properties of a compound, reduce toxicity and also alter the metabolism of the lead. Bioisosteric replacement is not simple replacement with another isostere but they are firstly analyzed by structural, solubility and electronic parameters to obtain molecules having similar biological activity. Few of the popular examples of the successful use of bioisosteres have been included. The objective of this review is to provide an overview of bioisosteric replacements which can be used for advance drug development.