What is the difference between classical isosteres and bioisosteres?

Classical Isosteres are molecules or ions with similar shape and often electronic properties. Many definitions are available. but the term is usually employed in the context of bioactivity and drug development. Such biologically-active compounds containing an isostere is called a bioisostere.

What are non classical bioisosteres?

non-classical bioisosteres can significantly differ in electronic distribution, physicochemical, steric and topological properties, they have found beneficial applications in drug discovery research. Nonclassical bioisosteres are subdivided into two groups: 1) cyclic vs.

What is the difference between isosteres types?

The key difference between isoelectronic and isosteres is that isoelectronic chemical species have similar electronic configurations whereas isosteres are chemical species having similar size, the same number of atoms and valence electrons.

What is bioisosterism in medicinal chemistry?

Bioisosterism is a strategy of Medicinal Chemistry for the rational design of new drugs, applied with a lead compound (LC) as a special process of molecular modification [1].

What are classical bioisosteres?

Classical bioisosteres

Classical bioisosterism was originally formulated by James Moir and refined by Irving Langmuir as a response to the observation that different atoms with the same valence electron structure had similar biological properties.

How do you identify bioisosteres?

Bioisosteric design involves replacing part of a molecule by another part that has similar properties. Such replacements may be identified by applying medicinal chemistry knowledge, by mining chemical databases or by choosing analogues similar in molecular physicochemical properties.

Why are bioisosteres important?

Introduction: A bioisostere is a powerful concept for medicinal chemistry. It allows the improvement of the stability; oral absorption; membrane permeability; and absorption, distribution, metabolism and excretion (ADME) of drug candidate, while retaining their biological properties.

What is Langmuir concept of bioisosterism?

The isostere concept was formulated by Irving Langmuir in 1919. The octet theory of valence indicates that if compounds. having the same number of atoms have also the same. total number of electrons, the electrons may arrange. themselves in the same manner.

What is meant by bioisosterism?

bioisosterism (plural bioisosterisms) (pharmacology) The relationship between bioisosteres, substituents or groups with similar physical or chemical properties that impart similar biological properties to a chemical compound.

What is isosteres example?

Noun. isostere (plural isosteres) (chemistry) Any of a group of molecules or ions that have the same number of valence electrons and have chemical or physical similarities. For example, SH, NH2 and CH3 are isosteres of OH.

What is meant by bioisosterism?

bioisosterism (plural bioisosterisms) (pharmacology) The relationship between bioisosteres, substituents or groups with similar physical or chemical properties that impart similar biological properties to a chemical compound.

What are the applications of bioisosteres that will continue to play an important role in drug discovery?

Abstract. Introduction: A bioisostere is a powerful concept for medicinal chemistry. It allows the improvement of the stability; oral absorption; membrane permeability; and absorption, distribution, metabolism and excretion (ADME) of drug candidate, while retaining their biological properties.

What is Langmuir concept of bioisosterism?

The isostere concept was formulated by Irving Langmuir in 1919. The octet theory of valence indicates that if compounds. having the same number of atoms have also the same. total number of electrons, the electrons may arrange. themselves in the same manner.

Who discovered bio Isosterism concept?

The description of this phenomenon as bioisosterism is attributed to Harris Friedman who introduced the term in 1951 to define compounds demonstrating similar biological activities [14].

What is bioisosteric replacement?

A bioisosteric replacement transforms an active compound into another compound by exchanging a group of atoms with another, broadly similar group of atoms.

What is a pharmacophore in drug design?

‘A pharmacophore is the ensemble of steric and electronic features that is necessary to ensure the optimal supra‐molecular interactions with a specific biological target structure and to trigger (or to block) its biological response’.

How bioisosterism is useful in drug design?

In drug design, the purpose of exchanging one bioisostere for another is : 1. To enhance the desired biological or physical properties of a compound without making significant changes in chemical structure. 2. To attenuate toxicity.

Which is used for Bioisosteric replacement of benzene?

The replacement of para-substituted benzenes with saturated bi- and polycyclic bioisosteres – bicyclo[1.1. 1]pentane, bicyclo[2.2. 2]octane and cubane, – often increases the potency, selectivity and metabolic stability of bioactive compounds.

What is drug metabolism in medicinal chemistry?

Drug metabolism is the chemical alteration of a drug via a biological system to aid its elimination by increasing its hydrophilicity. Drug metabolism occurs in two phases: Phase 1 includes oxidative reactions such as those undertaken by the cytochrome P450s, but also includes reduction and hydrolysis.

Which heterocyclic ring is used as bioisostere of an amide group?

Amide bioisosteric replacement with an oxadiazole ring leading to a potent and selective γ-secretase inhibitor.

Is fluorine an Isostere of hydrogen?

Fluorine as an Isostere of Hydrogen

The strategic introduction of fluorine to replace a hydrogen atom can markedly influence potency [25–30].

What are the 3 phases of metabolism?

The metabolism of xenobiotics is often divided into three phases:- modification, conjugation, and excretion. These reactions act in concert to detoxify xenobiotics and remove them from cells.

What are the 2 phases of drug metabolism?

Phase I reactions of drug metabolism involve oxidation, reduction, or hydrolysis of the parent drug, resulting in its conversion to a more polar molecule. Phase II reactions involve conjugation by coupling the drug or its metabolites to another molecule, such as glucuronidation, acylation, sulfate, or glicine.