In all metabolic processes in nature, electron transfer takes place at the molecular level. Two fundamental atoms in all living entities are oxygen (O) and nitrogen (N). In direct combination, they form NO, which is one of the most crucial biomolecules because it has a free electron ("free radical"). It is part of a universal communication system in biologicals cells.

If we go one level of abstraction higher, we find the amino (NH2) and the carboxyl (COOH) groups. In the carboxyl function, the electrons can migrate from one O to the other via the C atom (mesomerism). Thus, the H atom can easily migrate to the "partner" NH2 - the electrons are "free" and can participate in biological processes.

It is also why phenols, especially polyphenols (green tea EGCG, resveratrol, quercetin), are biologically very active. If both functional groups occur within one molecule, we have one of nature's most essential building blocks, amino acids.

With more atoms and larger molecules, the electron transfer becomes more complicated, but it can explain almost any drug's mechanism of action. It is perhaps interesting to note that electron transfer within biomolecules is sometimes completely different from what we know from the chemical laboratory.

That is why "free radicals" in the body are not generally harmful but vital.

SUMMARY

In summary, it is one of the most important functional groups in nature. That is the reason why it occurs as a functional group in so many drugs.

Attached you will find a link to a paper describing the effect of some functional groups in drugs.

https://www.eurekaselect.com/60961/article

Dear Pejman Rahmani Nejad ,

The answer to the question has several directions, in a few of them:

In the first place, the carboxylic group has inherent acid-base behavior. It may even form a carboxylic/carboxylate pair that acts as a buffer in some restricted pH range. The pH control propriety helps to stabilize and maintain pharmaceutic formulations.

The specific behavior directly affects the drugs' solubility and has been used to increase the salt formation and their solubility.

The carboxylic group will promote the drug framework's significant stability increase by inducing long-range H bond formation.

That particular property affects the final solubility and eventual interactions with some formulation components when some expected formulation decomposition or interactions occurs.

In the literature, you find examples of long-range interactions of carboxylic groups that affect enantiomeric interactions. 

For instance, Oxalates salts in some drugs like carvedilol oxalate crystallize as a standard racemic compound. The oxalate anions living in the inversion center are directly H-bonded to both R and S carvedilol enantiomers.  

The interaction forms racemic ionic units that extend along with the structure (Racemic salts and solid-solutions of enantiomers of the antihypertensive drug carvedilol Crystal Growth & Design, June 2019, Crystal Growth & Design 19(7)). 

All the above-cited effects are based on the direct drug structure itself. Similar effects are obtained if a salt drug with a carboxyl group is considered as the carvedilol oxalate.

That particular interest is mostly exploited in the engineered co-crystal, for suppling the pro-drug specie in the pharmaceutic industry, with already listed advantages in some drug systems.

The ability of immediate salt formation or, by contrast, protonation of the free conjugate-base affects the interactions and pharmaceutic actions. 

The list of possibilities that justify the several carboxyl group presence in drug structures would be long, based on a particular property at each time.

Nevertheless, the intense positive interference on the solubility, stabilization of drug structure, formulation, and intrinsic pH influence on the total pharmaceutic formulation may respond to carboxyl groups' significant presence in commercial drug structures.

Best regards,

WNM

Thanks a lot dear Prof. Wagner Da Nova Mussel

It has availability of various co-ordination sites, basically it exist as coo- so it can easily form bond with any in coming group like metal or the trap molecule. Over hydrolysis these bond break and the molecule release as it is.

Most of the effective medicines contains carboxylic group. They are involved in specific charge-charge interactions and are thus often critical for the binding of agents to their targets.

In all metabolic processes in nature, electron transfer takes place at the molecular level. Two fundamental atoms in all living entities are oxygen (O) and nitrogen (N). In direct combination, they form NO, which is one of the most crucial biomolecules because it has a free electron ("free radical"). It is part of a universal communication system in biologicals cells.

If we go one level of abstraction higher, we find the amino (NH2) and the carboxyl (COOH) groups. In the carboxyl function, the electrons can migrate from one O to the other via the C atom (mesomerism). Thus, the H atom can easily migrate to the "partner" NH2 - the electrons are "free" and can participate in biological processes.

It is also why phenols, especially polyphenols (green tea EGCG, resveratrol, quercetin), are biologically very active. If both functional groups occur within one molecule, we have one of nature's most essential building blocks, amino acids.

With more atoms and larger molecules, the electron transfer becomes more complicated, but it can explain almost any drug's mechanism of action. It is perhaps interesting to note that electron transfer within biomolecules is sometimes completely different from what we know from the chemical laboratory.

That is why "free radicals" in the body are not generally harmful but vital.

SUMMARY

In summary, it is one of the most important functional groups in nature. That is the reason why it occurs as a functional group in so many drugs.

Attached you will find a link to a paper describing the effect of some functional groups in drugs.

https://www.eurekaselect.com/60961/article

Ruediger Buchkremer

Thanks a lot, Sir

The importance of carboxylic group in the structure of drugs is that you can prepare water soluble salt with acid group by neutralization with alkali.

Carboxylic group imp. in the str.of drugs are production of polymer,biopolymers, coating,adhesives ,solvents etc.

Dear D. B. Dhangar

Could you please provide me some reference about things you've mentioned?

Thanks a lot for your reply

Thanks a lot for your reply dear professor Madhukar Baburao Deshmukh

Thanxs alot

Thanks for your comments

Prof.M.B.Deshmukh

Hi

To the best of my knowledge, most of drugs have carboxylic group because of the high activity to interact with receptor in body. Also, some of them are pro-drug, in turn, converting to their active form. Continually, functional group can affect the physiochemical of drugs which is dependent to multiple factors. For more information, you can enter the following link:

https://www.ashp.org/-/media/store-files/p2661-sample-chapter-2.ashx

Dear Sajjad Makhdoomi

Thanks a lot for your reply

They are acids so they can form salts that are more water soluble. Next, the carboxyl group can form hydrogen bonds with the receptors. Lastly, as acids they can form cocrystals that are now becoming important for property optimisation.

Dear Gautam R. Desiraju

Thanks a lot for your reply

Check this publication for more insight. "Prodrugs of Carboxylic Acids"

In the biochemistry of life systems and in drug design, the functional group of carboxylic acid plays a key role. In fact, a range of carboxylic acid-containing medicines, including commonly used anti-inflammatory anti-steroidal medications, antibiotics, anticoagulants and cholesterol-reduction statistics, have been marketed worldwide. This group is also a key determinant in drug-target interactions due to its acidity, combined with the ability to create relatively strong electrostatic interactions with hydrogen atom. However, the presence of carboxylic acid residues in a medication or candidate can be a liability despite the popularity of carboxylic acid medicines.

Banan Aldewachi

Thanks a lot for your reply

Best regards