Chemistry

### Definitions

color{green}("Drugs ") : Drugs are chemicals of low molecular masses (~100 – 500u).

● These interact with macromolecular targets and produce a biological response.

color{green}("Medicines ") : When the biological response is therapeutic and useful, these chemicals are called medicines and are used in diagnosis, prevention and treatment of diseases.

color{green}("Note ") : If taken in doses higher than those recommended, most of the drugs used as medicines are potential poisons.

● Use of chemicals for therapeutic effect is called chemotherapy.

•color{green}("Enzyme Inhibitors ") : Drugs inhibit any of the above mentioned activities of enzymes. These can block the binding site of the enzyme and prevent the binding of substrate, or can inhibit the catalytic activity of the enzyme. Such drugs are called enzyme inhibitors.

• color{green}("Competitive Inhibitors ") : Drugs compete with the natural substrate for their attachment on the active sites of enzymes. Such drugs are called competitive inhibitors.

• color{green}("Allosteric site ") : Some drugs do not bind to the enzyme’s active site. These bind to a different site of enzyme which is called allosteric site.

•color{green}("Chemical Messengers ") : In the body, message between two neurons and that between neurons to muscles is communicated through certain chemicals. These chemicals, known as chemical messengers are received at the binding sites of receptor proteins.

•color{green}("Antagonists ") : Drugs that bind to the receptor site and inhibit its natural function are called antagonists. These are useful when blocking of message is required.

•color{green}("Agonists ") : There are other types of drugs that mimic the natural messenger by switching on the receptor, these are called agonists.These are useful when there is lack of natural chemical messenger.

•color{green}("Tranquilizers ") : Chemical substances used for the treatment of stress, anxiety, irritability and mild or even severe mental diseases, are known as tranquilizers.

•color{green}("Narcotics ") :Drugs which produce sleep and unconsciousness are called narcotics. Mhese are habit forming drugs. For example, morphine and codeine.

•color{green}("Non-Narcotics ") :These are non-habit forming chemicals which reduce mild to moderate llatn such as headache, toothache, muscle and joint pain, etc. These are also termed as non-addicti,ve. These drugs do not produce sleep unconsciousness. Aspirin (2-acetoxybenzoic acid) is most commonly used analgesic with antipyretic properties.

•color{green}("Antimicrobials ") : An antimicrobial tends to destroy/prevent development or inhibit the pathogenic action of microbes such as bacteria (antibacterial drugs), fungi (antifungal agents), virus (antiviral agents), or other parasites (antiparasitic drugs) selectively.

•color{green}("Antibiotic ") : An antibiotic now refers to a substance produced wholly or partly by chemical synthesis, which in low concentrations inhibits the growth or destroys microorganisms by intervening in their metabolic processes.

•color{green}("Broad Spectrum Antibiotics ") : Antibiotics which kill or inhibit a wide range of Gram-positive and Gram-negative bacteria are said to be broad spectrum antibiotics.

•color{green}("Narrow Spectrum Antibiotics ") : Those effective mainly against Gram-positive or Gram-negative bacteria are narrow spectrum antibiotics.

•color{green}("Limited Spectrum Antibiotics ") : If effective against a single organism or disease, they are referred to as limited spectrum antibiotics.

•color{green}("Tincture of iodine ") :Iodine is a powerful antiseptic. Its 2-3 per cent solution in alcohol-water mixture is known as tincture of iodine. It is applied on wounds.

•color{green}("Antiseptics ") :These are the chemicals which either kill or prevent the growth microorganisms. Antiseptics are applied to the living tissues such wounds, cuts, ulcers and skin diseases in the form of antiseptic creams like furacin and soframycin.

•color{green}("Antifertility drugs ") :These are the chemical substances used to control the pregnancy. These are also called oral contraceptives. They belong to the class of natural products, known as steroids.

•color{green}("Aspartame ") : It is the most successful and widely used artificial sweetener.

•color{green}("Alitame ") : It is high potency sweetener, although it is more stable than aspartame, the control of sweetness of food is difficult while using it.

•color{green}("Sucrolose ") : It is trichloro derivative of sucrose.

•color{green}("Food preservatives ") :These are the chemical substances added to food to prevent their spoilage due to microbial growth (bacteria, yeasts and moulds) and to retain their nutritive value for longer periods .

•color{green}("Saponification ") : Soaps containing sodium salts are formed by heating fat (i.e., glyceryl ester of fatty acid) with aqueous sodium hydroxide solution. This reaction is known as saponification.

•color{green}("Anionic detergents ") : These are sodium salts of sulphonated long chain alcohols or hydrocarbons.

•color{green}("Cationic detergents "): Cationic detergents are quarternary ammonium salts of amines with acetates, chlorides or bromides as anions.

•color{green}("Non-ionic detergents "): Non-ionic detergents do not contain any ion in their constitution. One such detergent is formed when stearic acid reacts with polyethyleneglycol.