Drug

Any chemical substance that is used for diagnosis or treatment of disease is called drug.

Classification of drug on the basis of sale:-

Over the counter (OTC)

• OTC is the group of drug that do not require any prescription for dispensing/sale.
• For example:

1. Multivitamins
2. Laxatives
3. NSAIDS(nosteroidal anti-inflammatory drug).

Prescription only medicines (POM)

POM is the grupo drug that must require prescription for dispensing/ sale.

1. Antibiotics
2. Antidiabetics
3. Steroids
4. Antihypertension

Classification of drug on the base of sources :-

1. Natural source
2. Semi- synthetic source
3. Synthetic source

Natural source

Drugs which are obtained from natural source are called natural drugs.

It includes;

• Plant source
• Animal source
• Microbial source

Plant source:-

Does that obtain from plant are called plants source.

• Digoxin
• Respirin
• Atropine

Animal source:-

Drugs are obtained from animals are called animal source.

• Vaccine
• Hormone
• Insulin

Microbial source:-

Drugs are obtain from microorganisms are called microbial source.

• Vaccines
• Insulin
• Antibiotics

Semi- synthetic source

Drugs that are the combination of natural and synthetic source are called semic synthetic source.

• Amoxicillin
• Cefixime

Synthetic sources

Drugs which are synthesize in laboratory are called synthetic sources.

• Paracetamol
• Aspirin.

Names of drugs

Generic name of drugs:-

Name of drag on scientific basis is called generic name. It is also called as salt name.

For example;

Aspirin

Chemical name :-

Name of drug on the base of chemical present in it. Is called chemical name.

For example;

Acetylsalicyclic acid is a chemical name of aspirin.

Brand name:-

Name of drug given by manufacturer is called brand name.

For example;

Disprine is a brand name of aspirin.

Surface tension

Cohesive forces:

Force of attraction between the molecules of the same substances is called cohesive forces.

Adhesive forces:

Force of attraction between the molecules of the different substances is called adhesive forces.

Like a solid and liquid substances.

Surface tension:

It is the property of surface of liquid that allows it to resist an external force, due to cohesive nature of its molecules.

For example;

Surface tension is the reason why raindrops and oil drops are spherical in shape.

Applications of surface tension

1. Chemical activity of drug depends upon surface tension of its molecules.
2. Absorption of drug depend upon surface tension of its molecules.
3. Dissolution of drug depends upon surface tension of its molecules.
4. Bioavailability of drug depends upon surface tension of its molecules.
5. Product quality of drug depends upon surface tension of its molecules.

Viscosity

Internal friction of moving fluid is called viscosity.

Viscometer

An instrument which is used to find out the viscosity of any fluid is called viscometer. It is also called a rehometer

Applications in pharmacy

• Concept of viscosity helps to prepare different dosage form.
• It helps in preparation of eye drops.
• It helps in preparation of airdrops.
• It helps in preparation of nasal drops .
• It helps in preparation of emulsion and syrups.
• Methylcellulose and hydroxy methylcellulose are viscosity enhances and are used to ophthalmic solution to increase viscosity.

Ionization

• Ionization is a process by which an atom obtain a positive or negative charge by gaining or losing electron.
• Ions can be formed by heat radiation or chemical reaction.
• Thus energy source is important.

Applications of ionization

1. Concept of ionization helps to understand absorption of drug.
2. Concept of ionization helps to understand distribution of drug.
3. Concept of ionization helps to to understand elimination of drug.
4. Concept of ionization helps inin manufacturing of drug.