Nature of drugs that we should know

 

INTRODUCTION

    Everybody in their lifetime has taken drugs not the illegal ones but the drugs that a doctor prescribes us when we fall ill. Maybe we sometimes self prescribe our drugs and end up having some OTC drugs. Many of the drugs we use have different natures like we can say they have different properties. So here we may learn about a few of them to get a view of the nature of some of the drugs that we might have taken.

1. Nature of drugs

Drugs are basically substances that bring about a chemical reaction in our body be it beneficial or harmful. Now one might ask how these chemical reactions are triggered by a simple pill that we take.

Well, it's by the chemicals that they contain ie. The chemical in the pill we take can be an agonist or an antagonist.

Agonists are those chemicals which bind to the receptors in our body and activate the chemical pathway again which might have been disturbed. Antagonists do the opposite ie. They inhibit the chemical process that is going on in the body by binding to their receptors.

Now one might think then we need to take drugs to keep our bodily reactions going on, but no the substances that are needed to maintain these functions are naturally produced in the body. Which means our body does produce drugs for smooth functioning and they can be enzymes, hormones, etc.

We only need drugs or those substances when the body is not producing them in a balanced manner.

Another nature of drugs is that they can be toxic to the body and they are called poisons and there is a dedicated field of study for that called toxicology which studies about drugs that are harmful to the body.

 

2. Physical nature of drugs

Now the drugs are available in a pharmacy and we can say that the pharmacies are lit shops. The drugs come in very different shape sizes and often colors. Scientifically speaking the drugs have different sizes, shapes, atomic composition, chemical composition and even the way they are administered to the body is different.

So why is there so much diversity in drugs?

Because it all comes to the usefulness of the drug must reach to the action site to perform the function that it’s taken for and then it should stay there for the appropriate time and can be excreted with minimum or no complications.

At room temperature, various drugs can be present in all the three states ie. Solid (aspirin, atropine), liquid(nicotine and ethanol) or gas(nitrous oxide) and these states can also decide the way of administering a drug.

Other forms of drugs can be inorganic (lithium, iron), organic acid-base, etc.

 

3. Size and shape of the drugs

The size of the drug varies greatly as of lithium mw=7 and that of Ateplase= 59050 (it’s a protein). But most drugs vary from 100 to 1000 in molecular weight. Besides that there are other factors like the shape (it should fit the receptor), the charge on the molecule all should be accurate and thus the most cases the MW is 100.

Now, our body has a function called diffusion and thus dugs of large molecular size like more than 1000 cannot pass through the compartments so they are directly administered to the site of requirement. Like, let us take Ateplase which is a clot-dissolving a protein having very large MW is directly infused in the vascular compartments.

So, the size of the drug may define how the drug is administered to the body.

4.  Drug reactivity and drug-receptor bonds

The drug that goes into the body makes different types of bonds with the receptors of which are covalent bonds which are the strongest. Covalent bonds are very strong and in many cases not reversible under biologic conditions. Thus, the covalent bond formed between the acetyl group of acetylsalicylic acid (aspirin) and cyclooxygenase, its enzyme target in platelets, is not readily broken. And the platelets need to synthesize new enzymes which might take several days.

Next types of bonds are the electrostatic bonds which are less strong and other than that are the hydrophobic bonds which are present between lipids.

Now all this talk about the bonds of the molecule of the drug and the receptor is of little importance, because what we know is that the drugs that bind through weak bonds are more selective than strong bond drugs.

But why and how does it matter?

Its because if we have a highly selective short-acting drug then the receptors that fit the drug are very few. If we make a strong bond then it will be hard to break then the weak ones.

 

5. Rational drug design

Its basically about the molecular structure of the drug that is made to fit its biologic receptor. For a drug to work on mechanism weather be for activation or inhibition the drug should be fit to the receptor. It’s not so much of an explored area as till recently drugs were based on the chemical reactions. This field has been achieved by computer designs of drugs in the last few decades and more designs might come in the future.

 

6. Receptor nomenclature

In the recent times the discoveries of the receptors of the drugs have contributed to a very confusing naming pattern of the same. So the IUPHAR has been the suggestion for the drug classification and naming receptors and it’s widely used.

 

Conclusion

So the drugs that we take have nature a particular property and they do have some function in the body and there is a mechanism of action of the drug. Nature says that drugs whether prescribed or not interfere with the body mechanism to either make it better or worse.

 

That’s why it’s always advised to take drugs after prescribed by a qualified personnel only.

 

So be wise and take care!!!!!