2. Pharmacology
The word Pharmacology is derived from the Greek words Pharmakon
(which means Drug) & Logos (which means Study).
Thus Pharmacology defined as the "Study of substances that deals with
the knowledge of drugs & their interactions with living organisms
through chemical processs by binding to the regulatory molecules."
Pharmacology is a branch of medicine that includes history,sources, uses,
methods of administration, absorption,distribution,metabolism, excretion,
biotransformation & effects of drugs.
3. Historic development of pharmacology
▪ Pharmacology is one of the cornerstones of the drug discovery process.
Pharmacology as a branch of science is quite young one. The birth date of
pharmacology is not as clear-cut. In the early 19thcentury, physiologists performed
many pharmacologic studies.
▪ Oswald Schmiedeberg is recognized as the founder of modern pharmacology. He
established the idea of experimental physiology.
▪ Pharmacology depends largely on experiments conducted in laboratory animals, but
even the human animal may be used as a test subject.Friedrich Serturner, the German
pharmacist who isolated the first alkaloid from opium in 1805. The alkaloid was
named as Morphine.
4. Worlds oldest pharmacology - from India and China
Materia medica (2735 B.C.) by Pan Tsao- contained mainly Plant and
metal with few animal products
Ayurveda - described by Charaka accordig to Rigveda (3000 B.C.) -
includes 300 vegetable drugs , classified into 50 groups according to their
effects on symptoms.
Papyrus (1500 B.C.) discovered by Eber -700 drugs
Modern medicine (from 450 B.C.) by Hippocrates- concept of disease as
a pathologic process and organize pharmacology on the basis of
observation, analysis and deduction.- use simple and efficacious drugs.
5. Allopathay (James gregory, 1753-1821) -treatment without any rational basis-
use symptomatic treatment with obnoxious remedis.
Homeopathy (Hanneman, 19th century)- likes cures like, and dilution potentiate
the action of drugs.
Modern Pharmacology (Francois Magendie and Claude Bernard)-helps to
elucidate basic physiological and pathological mechanisms in diseases.
pharmacology provide scientific data to form the basis of rational therapeutics
depending on different animal experiments designed to study the effect of
drugs.
6. Division of pharmacology
1. Clinical Pharmacology : It is the branch of pharmacology that deals with the
scientific study of drugs in humans for the safe & effective use of drugs.
It is of 2 parts :
a) Pharmacodynamics : The word is derived from Greek words Pharmakon
(drugs) & Dynamics (power).
It is the study of biochemical & physiological effects of drugs & their mechanism of
action. Simply means , "What the drug does to the body?"
b) Pharmacokinetics : The word is derived from Greek words Pharmakon
(drugs) & Kinetics (movement).
It is the study of absorption, distribution, metabolism & excretion of drugs.
Simply means , "What the body does to the drug."
7. 2) Pharmacy : It deals with the preparing,preserving,compounding,handling &
dispensing.of drugs. It includes PG,Pharmaceutical chem & Biopharmaceutics.
3) Therapeutics : It deals with the use of drugs in human to prevention,
treatment,mitigation & cure of diseases.
4) Toxicology : It deals with the study of poisonous effects of drugs on living
organisms & their management.
5) Chemotherapy : It deals with the treatment of systematic infection with
specific drugs that have selective toxicity for the infective cell with no or
minimal adverse effects on the host cells.
6) Pharmacogenetics : Study of the genetic variations that cause differences in
drug response.
7) Pharmacoeconomics : Study of the cost of medicine taking into acount.
8. Pharmacopoeia
Pharmacopoeia is an official book of publication, recognised by legal authorities
which contains the list of-
Name & description of the drugs & medicinal substances with their natural origin
Formulas for chemical preparation of them
Test for their identity,purity & potency
Usage of drugs & medicine
Dose & dosage forms
Most of the developed countries have their own pharmacopoeia like BP, USP, AP, IP.
BD doesn't have any pharmacopoeia of itself. BD usually follows BP & USP.
Formulary
Formulary is a list of available drugs with descriptions, tests & formulas for preparing
the same that are available to prescribers in the respective countries.
Some example includes- BDNF, BNF, ANF etc.
9. Difference between Pharmacopoeia & Formulary :
Pharmacopoeia Formulary
It is an official Publication It is an unofficial Publication
Published by legal authorities Published by Drug
administration authority
Brand names aren't included Brand names are included
Can be followed by physicians
of whole over the world
Can't be followed by physicians
of whole over the world
Published less frequently (5
yearly or more)
Published more frequently
(yearly or two yearly)
10. Drug
The drug is derived from French word Drogue which means "A dry herb."
According to W.H.O. " A drug is any substance or product that is used or
intended to be used to modify or explore physiological systems or pathological
states for the benefit of the recipient."
Most of the drugs are obtained from extraction of various medicinal plants. Sources Of
drugs include :
1.Mineral: liquid paraffin, MgSO4.
2.Animal: Insulin, heparin
3.Plant: Atropine, morphine
4.Synthetic: Aspirin, sulfonamide.
5.Microorganisms: Antibiotics, streptomycin
6.Genetic engineering: gene transfer- mediated vaccination.
Usually drugs are taken by inhaled,injected,absorbed or dissolved. Drugs don't
have suitable dosage form. They may have positive or negative effects on body.
11.
12. Drug nomenclature
Any drugs may have names in all 3 of the following classes :
1.Chemical name : It is the name used by the organic chemist to indicate the chemical structure
of drug. ex : N-(4-hydroxyphenyl)ethanamide.
2.Non-proprietary (generic) name: It is used in pharmacopoeias & recognised by the official
bodies. ex : Paracetamol, Omeprazole.
3.Proprietary (Brand) name : It is the commercial name used by the pharmaceutical companies.
ex : Napa, Seclo/Losectil
Prodrug
▪ Prodrug defined as the chemical that is readily absorbed,distributed & then converted to the
active drug by biological process inside the body.
Prodrug don't produce any pharmacological effects until they chemically altered within the
body. Examples : Aspirin & Codein is the prodrug of Salicylic acid & Morphiine respectively.
▪ Advantages of Prodrug : 1)It modifies A,D,M,E. 2)It increases bio-availability.
3)It reduces adverse effect & toxicity. 4)It reduces 1st pass hepatic metabolism.
13. Nature of Plant products
1) Alkaloid : Alkaloids are organic nitrogenous compounds of plant origin that contain
one or more nitrogen atom in their heterocyclic ring which has physiological and
pharml effects on body.
ex : Pipiridine, pyridine, purine, tropane.
2) Glycosides : Glycosides are non-reducing organic compounds that on hydrolysis with
acids produces : Glycon & Agyclone. They are linked by glycosidic linkage.
ex : Salicin, sinigrin, digitoxin.
3) Flavonoids : Flavonoids are group of Polyphenolic compounds having a benzo-Y-pyrone
structure. ex : Catechin, quercetin.
4) Resins : Resins are more or less solid, amorphous products of complex chemical nature.
On heating they soften & finally melt. e.g. Benzoin, Japlap
14. 5) Tanins : Tanins are non-nitrogenous complex natural organic compounds,
polyphenolic & poly hydroxy benzoic acid derivatives. e.g. Catechin, pala catechu
6) Oils:
• Fixed oils: glycerides of oleic, palmitic and stearic acids. E.g. peanut oil, castor
oil.
• Volatile/ esssential oils: The odorous, volatile principle of plant & animal
source. e.g. clove oil, cinnamon oil.
• Mineral oils : liquid paraffin.
7 ) Gums : Secratory product of plants. Dispersible in water..
8) Antibacterial substances: Derived from mold , fungus etc.
15. OTC drugs
OTC drugs means Over the trade drugs referred to the drugs that are sold directly to the
consumer without any prescription. Thereby, they are also known as non-prescription drugs.
Examples : Paracetamol, omeprazole, antacid, ORS etc.
OTC drugs are easily available & comparatively cheap. They decrease the load of
hospitalization. Treatment of minor illness can be done easily by them.
INN drugs
INN (International Non-proprietary Names) are the most recent drugs which haven't been
included in the pharmacopoeias but still are being used globally.Ex: Iron polymatose.
The INN drugs are managed by WHO. The main purposes of INN drugs is to clear
identification, safe prescription & despensing of medicines to patients.
A prescription is an written by a physician,dentist or any other medical practitioner to the
pharmacist for compounding & despensing specific medication to the patient.
A prescription contains of some parts. These are : Date, patient's details, superscription,
inscription, subscription & prescriber name,address & signature.
16. First pass metabolism
▪ First pass metabolism is a process in which a drug administrated by mouth is absorbed
from the GIT & transported via portal vein to the liver, where it is metabolized. As a
result concentration of a drug is greatly reduced before it reaches the systemic
circulation. This first pass through the liver thus greatly reduces the bioavailability of
the drug.
▪ The 4 primary systems that affect the first pass of a drug are enzymes of
gastrointestinal lumen, gut wall enzymes, bacterial enzymes & hepatic enzymes.
▪ Alternative routes of drug administration like parenteral, Sublingual & rectal routes
avoide the first pass effect because they allow the drugs to be absorbed directly into the
systemic circulation.
19. Route of drug administration means way of getting a drug into the body. It's
classified into 2 categories mainly:
1) Enteral : Refers the routes from the mouth to the rectum where the drug
is passed through the GIT. There are 4 enteral routes of administration :
Oral,Sublingual,buccal & rectal.
2) Parenteral : Routes through which the drug directly reaches the body
fluids. Here, injection or infusion is induced by means of a needle or catheter
inserted into body.
Drugs come in many forms & many factors determine the choice of
route of drug administration. These are :
1) Physical and chemical properties of drugs- solid /liquid / gas/
solubility/ stability, irritancy
20. 2) Site of action :
a. Local effect : Occurs when the drug activity is at the site of administration.
(e.g. eyes, ears, nose skin)
b. Systemic effect : Occurs when the drug is introduced into the circulatory
system by any route & carried by the blood to the site of action.
3) Onset of action: When rapid onset of action is required, most of the drugs are
administered parenterally.
4) Duration of action of drugs : a. Prolonged action- Transdermal, subcutaneous
b. Slow & sustained- Subcutaneous, intramascular
5) pH of drugs : a. Basic drugs- Intravenous route b.Acidic drugs-Any route
6) Bioavailability : a. High bioavailability- IV route b. Low- Any route
7) Severity of disease: a. Severe condition- IV route b. Stable- Any route
8) Condition of patient : a. Unconscious patient- IV or rectal b. Conscious-any
21. Oral route
Oral route is the most common & convenient systemic route. Here the medication is
applied topically to the mouth & the drug is absorbed from the stomach & small
intestine.
▪ Advantages :
1) Safest & convenient route
2) Painless method
3) Cost effective
4) No maximal/strict sterilization is
required
5) No extra skill required,self medication
is possible.
▪ Disadvantages :
1) Slow absorption of drug, hence slow
action.
2) Unpalatable & bitter drugs may be
unpleasant in taste
3) Not useful for unconscious & vomitting
patients.
4) Effect is too slow in case of emergency
5) Drugs may undergo 1st pass effect in the
liver
6) Some drugs get destroyed by gastric
secretion
22. Sublingual/Buccal Route:
Here the drugs are taken as smaller tablets, which are held in the mouth(buccal) or
beneath the tongue(sublingual). The route has special importance for certain drugs.
e.g. Motrogly is effective when given in S/l route but ineffective when given orally.
▪ Advantages :
1) Painless method
2) Cost effective
3) No maximal/strict sterilization is
required
4) No extra skill required,self medication
is possible.
5) Drug absorption is quick by S/l mucosa
6) Rapid onset of action.
7) 1st pass effect avoided.
▪ Disadvantages :
1) Irritation of oral mucosa may occur
2) Unpalatable & bitter drugs may be
unpleasant in taste
3) Not useful for unconscious & vomitting
patients.
4) Large quantities of drugs can't be given
23. Rectal route :
The drug is given rectally for systemic effect. The drug administrated either in solid
forms like suppositories or in liquid forms like enema .
▪ Advantages
1) Suitable for unconscious & old
patients.
2) Irritant & unpalatable drugs can be
given.
3) Drugs aren't destroyed by enzymes.
4) Less scope of 1st pm than other
enteral routes.
▪ Disadvantages :
1) Inconvenient & embrassing process.
2) Absorption is slow & erratic.
3) Slow onset of action.
4) Inflammation of rectal mucosa may
occur.
5) Can't be given in diarrhoea or
dysentery.
24. Inhalational
It provides rapid delivery of drugs across the large surface area of respiratory tract. In
this way drug can pass directly to the lungs. Drugs used involve volatile drugs & gases.
▪ Advantages :
1) Rapid onset of action.
2) Rapid absorption of drugs.
3) 1st pass effect avoided.
4) Self medication is possible.
▪ Disadvantages :
1) Special apparatus is required.
2) Fewer dose can be given at a time
3) Irritation of respiratory tract may
take place
4) difficulties in regulating the exact
amount of dose.
25. Intravenous route
Most common Parenteral route for the drugs that aren't absorbed orally. The drug
is injected or infused directly into the blood stream via veins.
▪ Advantages :
1) Bioavailability is 100%
2) Rapid onset of action.
3) 1st Pm avoided.
4) Suitable for irritant & unpalatable
drugs.
5) Suitable for vomitting & unconscious
patients.
6) No food-drug interaction occur.
7) Mild irritants can be given.
▪ Disadvantages:
1) Irritation of vein can cause
thrombophlebities.
2) Local abscess & pain.
3) Chance of infection.
4) Relatively expensive than enteral
drugs.
5) Technical assistance is required.
6) Cannot be recalled by strategies
such as emesis or by binding to
activated charcoal.
26. Intramascular route
Drug injected into the skeletal muscle like deltoid, gluteus, rectus femoris.
▪ Advantages :
1) High Bioavailability (75% to <100%)
2) Rapid onset of action.
3) 1st Pm avoided.
4) Suitable for irritant & unpalatable
drugs.
5) Suitable for vomitting & unconscious
patients.
6) No food-drug interaction occur.
7) Mild irritants can be given.
▪ Disadvantages :
1) Only upto 10 ml of drug can be given.
2) Local abscess & pain
3) Chance of infection with necrosis.
4) Relatively expensive than enteral
drugs.
5) Technical assistance is required.
6) Cannot be recalled by strategies
such as emesis or by binding to
activated charcoal.
27. Subcutaneous route
The drug is injected under the skin. Drug is absorbed in the SC tissues.
▪ Advantages :
1) High Bioavailability (75% to <100%)
3) 1st Pm avoided.
4) Suitable for bitter & unpalatable drugs.
5) Suitable for vomitting & unconscious
patients.
6) No food-drug interaction occur.
7) Minimized the risks associated with IV
inj.
▪ Disadvantages :
1) Absorption is slow due to less vascular
tissues.
2) Irritants can't be given.
3) Only small volume (upto 2ml) can be
injected.
4) Local abscess & pain
5) Chance of infection with necrosis.
6) Cannot be recalled by strategies
such as emesis or by binding to
activated charcoal.
28. Intradermal route
The drug is injected into the skin layer(dermis). The drug is slowly absorbed. Only
small amounts of drug can be given.
Transdermal route :
• This route of administration achieves systemic effects by application of drugs
to the skin, usually by transdermal patch. The rate of absorption depends upon
the physical characteristics of skin at the site of application.
• This route is most often used for the sustained delivery of drugs, such as the
antianginal drug nitroglycerin, the antiemetic scopolamine.
29.
30. Topical routes
Topical routes are used when a local effect of the drug is required. The drug is
applied to the skin surface or mucas membrane in the form of Ointments, creams,
lotions and powders .
▪ Advantages :
1) Local therapeutic effects.
2) Lower risk of side effects.
3) Relatively Cheaper than parenteral
products.
4) No 1st Pm takes place.
5) The drug can be self administered.
▪ Disadvantages :
1) Absorption is slow.
2) Effect is slow.
3) Skin irritation or necrosis may occur.
4) Irritants can't be given.
5) The dosage is difficult to control.
31. Deeper tissue:
Certain deep area can be approached by needle and syringe: no systemic absorption.
Intra -arterial supply: angiography.
Intra-articular: hydrocortisone inj.
Intrathecal : Lignocain inj.
