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1. General pharmacology
NIKHIL GANGADHAR SONTAKKE

2. OBJECTIVES
At the end of this session we will able to understand :
• Introduction of pharmacology
• Define drugs ?
• Sources of the drugs
• Dosage forms of Drugs
• Routes of drug administration

3. Pharmacology
• Pharmacology is a science of drug [ Greek :
Pharmacon – Drug , Logous – Discourse in (The
science) ]. In broad sense, it deals with the
interaction of exogenously administered chemical
molecules with living System,
OR
• It is the science that deals with the drugs known as
pharmacology.

4. DRUG
•It is the single active chemical entity present in a medicine
that is used for diagnosis prevention and treatment of a
disease.
•Every drug is a medicine but every medicine is not a drug .
•Clinically drugs used for :
 Diagnosis : barium salt
 Prevention : Vaccines
 Cure : Antibiotics
 Global effects : General Anesthesia

5. Sourcesof Drugs
• Drugs are obtained from various sources.
•Drugs may be synthesized within the body (hormones) or
not. i.e. xenobiotics (from the Greek xenos, meaning
"stranger").

6. According to sources they are:
1. Natural drugs :
A. Plants :
Examples :
•Digoxin from Digitalis purpurea.
•Atropine from Atropa belladonna .
•Quinine from Cinchona officinalis.
B. Animals :
Examples :
• Insulin from pork/beef .
•Cod liver oil from Cod fish liver.
•Adrenaline and Thyroxine

7. C. Minerals :
Eg: Iron, Iodine, Potassium salts.
D. Microorganisms :
Eg:
•Penicillin from penicillium notatum.
• Chloramphenicol from Streptomyces venezuelae
(Actinomycetes).

8. 2. Synthetic drugs:
prepared by chemical synthesis in pharmaceutical
laboratories.
E.g. Sulphonamides, quinolones, barbiturates.
3. Semi-synthetic drugs:
prepared by chemical modification of natural drugs.
E.g.. a) Ampicillin from penicillin G .
b) Dihydroergotamine from ergotamine.
4. Biosynthetic drugs:
prepared by cloning of human DNA in to the bacteria
like E.coli.
E.g. Human insulin (humulin), human GH.

9. Types of dosage forms
According to physical form a drug ,
1. Solid
a. Tablets – conventional
- chewable
- sublingual
- extended release
b. capsule – hard gelatin and soft gelatin.
c. Suppositories
d. Pills
e. Powders

10. 2. Liquid
a . solutions
b. suspensions
c. Emulsions
d. Syrups.
3. Semisolids :
a. Ointments
b. Creams
c. Paste
d. Jellies

11. According to on set of Action Slow Absorption
•Orally (swallowed )
•Through mucus membrane ,
a. Oral mucosa (E.g. Sublingual )
b. Nasal mucosa
•Topical / Transdermal (Through skin )
•Rectally (Suppository)

12. According to on set of Action Faster Absorption
•Parenterally (injection)
- Intravenous (IV)
- Intramuscular (IM)
- Subcutaneous (SC)
- Intradermal (ID)
- Intraperitoneal (IP)
•Inhaled (Through lungs )

13. Routes of drug administration

14. Routes of drug administration
Systemic route Local route
Enteral Parenteral
 Skin Topical
 Intranasal
 Ocular drops
 Mucosal (Throat ,
vaginal , Mouth ,
Ear.)
 Inhalation
 Transdermal
 Oral
 Sublingual
 buccal
 Rectal
 Inhalational
 Transdermal
 Injections
- Intravenous (IV)
- Intramuscular (IM)
- Subcutaneous (SC)
- Intradermal (ID)
- Intraperitoneal (IP)
- Intraarterial
- Intraarticular

15. Factors governing choice of route
1.Physical and chemical properties of the drug
(solid/liquid/gas; solubility, stability, pH, irritancy).
2. Site of desired action-localized and approachable or
generalized and not approachable .
3. Rate and extent of absorption of the drug from different
routes.

16. 4. Effect of digestive juices.
5. Rapidity with which the response is desired (routine
treatment or emergency)
6. Accuracy of dosage required (iv. and inhalational can
provide fine tuning).
7. Condition of the patient (unconscious, vomiting ).

17. Systemic Route
Systemic administration is a route of administration of
medication, nutrition or other substance into the
circulatory system so that the entire body is affected.
The systemic routes are:
Oral
Sublingual or buccal
Rectal

18. ORAL ROUTE
The most common route of drug administration. The drug
is given through oral cavity.
ADVANTAGES :
 It is safe.
 It is convenient self administrated drug.
 Pain free.
 Noninvasive and easy to take .
 Economical compare to other parenteral route.
 No need for sterilization.

19. DISADVANTAGES :
 Some times inefficient – only part of the drug may be
absorbed.
 Irritation to gastric mucosa – nausea and vomiting
 Destruction of drugs by gastric acid and digestive juices
 Effect too slow for emergencies
 Unpleasant taste of some drugs

20. BUCCAL ROUTE
 Buccal administration is where the dosage
form is placed between gums and inner lining
of the cheek (buccal pouch) .
Absorbed by buccal mucosa

21. ADVANTAGES
- Avoid first pass effect
- Rapid absorption
- Drug stability
DISADVANTAGES
- Inconvenience
- advantages lost if swallowed
- Small dose limit

22. Sublingual Route
ADVANTAGES :
 Economical
Quick termination
First-pass avoided
 Drug absorption is quick
Can be self administered
Disadvantages :
Unpalatable & bitter drugs
Irritation of oral mucosa
 Large quantities not given
 Few drugs are absorbed

23. Rectal Route
ADVANTAGES:
Used in children.
 Little or no first pass effect.
Used in vomiting/ unconsciuos .
Higher concentrations rapidly achieved.
DISADVANTAGES :
Inconvenient.
Absorption is slow and erratic.
Irritation or inflammation of rectal mucosa can occur .

24. Parenteral Route
Parenteral administration is injection
or infusion by means of a needle or catheter
inserted into the body.
• The term parenteral comes from Greek words.
□para, meaning outside
□ Enteron, meaning the intestine.This route of
administration bypasses the alimentary canal

25. Intravenous Route
ADVANTAGES :
BIOAVAILABILITY 100%.
DESIRED BLOOD CONCENTRATIONS ACHIEVED.
 LARGE QUANTITIES.
 VOMITING & DIARRHEA.
EMERGENCY SITUATIONS.
FIRST PASS AVOIDED.
GASTRIC MANUPALATION AVOIDED
DISADVANTAGES :
IRRITATION & CELLULITIS.
THROMBOPHELEBITIS.
 REPEATED INJECTIONS NOTALWAYS FEASIBLE.
LESS SAFE.
TECHNICAL ASSISTANCEREQUIRED.
DANGER OF INFECTION.
EXPENSIVELESS CONVENIENT AND PAINFUL.

26. Intramuscular Route
Advantages:
 Absorption reasonably uniform.
 Rapid onset of action for drugs in aqueous solution.
Mild irritants can be given.
 Repository and slow release preparations.
 First pass avoided.
Gastric factors can be avoided
Disadvantages:
Only up to 10ml drug given.
 Local pain and abscess.
Expensive.
Infection.
Nerve damage

27. Subcutaneous Route
• Injected under the skin.
• Absorption is slow, so action is prolonged.
• IMPLANT :a tablet or porous capsule is inserted into the loose tissues by incision of the
skin, which is then stiched up. example: certain hormonal drugs.
Advantages :
• Self-administration is possible (e.g. insulin).
• Depot preparations can be inserted into the subcutaneous tissue.
• It is a good route of administration especiallyin skin infections.
• It is relatively safer than I.M. and I.V.
Disadvantages
• It is suitable only for nonirritant drugs.
• Drug absorption is slow; hence it is not suitable for emergency.
• More expensive than oral.
• Some drugs can irritate tissue and cause pain.

28. INTRADERMAL
•drug is given within skin layers (dermis)
•Painful Mainly used for testing sensitivity to
drugs.
e.g. penicillin, ATS (anti tetanus serum)
INOCULATION :administration of vaccine (like
small pox vaccine)

29. Local Route
These routes can only be used for localized lesions at
accessible sites and for drugs whose systemic absorption from
these sites is minimal. e.g. glyceryl trinitrate (GTN) applied on the
skin as ointment .
Thus, high concentrations are attained at the desired site
without exposing the rest of the body.

30. Topical Route
•Topical administration is the application of a drug directly
to the surface of the skin . Includes administration of
drugs to any mucous membrane.

31. Topical Dosage Forms
Dose forms for topical administration include:
Skin:
• Creams.
• Lotions
• Gels.
• transdermal patches.
• ointments.
 Eye or ear:
• Solutions
• Suspensions
• ointments.
Nose and lungs :- sprays and powders

32. Advantages :
Local therapeutic effects.
Lower risk of side effect.
Transdermal route offers steady level of drug in the system
Disadvantages :
Not well absorbed into the deeper layer of the skin or mucous membrane.

33. Route for administration -Time until effect
• Intravenous 30-60 seconds
• Intraosseous 30-60 seconds
• Endotracheal 2-3 minutes
• Inhalation 2-3 minutes
• Sublingual 3-5 minutes
• Intramuscular 10-20 minutes
• Subcutaneous 15-30 minutes
• Rectal 5-30 minutes
• Ingestion 30-90 minutes