CHAPTER 1.1. General Introduction to drugs CHAPTER 1.2 Routes of oral administration and dosage forms

1. Introduction to Synthetic
Drugs & Dyes
T.Y. B.Sc. Semester-V
Prepared by
Prof. Pravin Bendle
Assistant Professor
N.G.Acharya and D.K.Marathe College, Chembur

2. TY B.Sc.Semester -V
Paper -5 Chemistry of Drugs
Mumbai University
Unit –I
Chapters
1.1 General Introduction to Drugs
1.2 Routes of Drug Administration & Dosage Forms

3. 1.1 General Introduction to Drug
• Drug ( Derived form French word “Drougue”)
• Definition
• A substance which is utilized in the prevention ,diagnosis ,treatment or cure
of disease in man or other animals.
• According to WHO
• “ Any substance which is used or intended to be used for modifying or
exploring physiological systems or pathological systems or pathological states
for the benefits of the recipient”

4. Requirements of Ideal Drugs
• Its actions should be localised at the site where it is desired to act.
• It should act on a system with efficiency and safety.
• It should not have any toxicity.
• It should have minimum side effects
• It should not injure the host tissue &/or physiological process.
• The cells should not acquire tolerance or resistance to the drug after
prolonged use.

5. Classification of Drugs
• On the basis of therapeutic action :
i. Pharmacodynamic agents
ii. Chemotherapeutic agents
iii. Vitamins
iv. Hormones

6. Pharmacodynamic agents
• These are the drugs which act on various physiological functions of the body.
• Classification :
i. Non selective CNS depressants
ii. Selective Modifiers of CNS
iii. CNS stimulants
iv. Adrenergic stimulants & blocking agents
v. Histamines & antihistaminic agents
vi. Local anaesthetics
vii. Cardiovascular agents
viii. Haemtological agents
ix. Diuretics

7. Chemotherapeutic agents
The treatment of infectious diseases by using a chemical agent is called as
chemotherapeutic agents.
Types of Chemotherapeutic agents:
• Organometallic compounds
• Anthelmintics
• Antiprotozoals
• Antimalarials
• Antifungal
• Antiviral
• Antiseptics
• Antibacterials (sulpha drugs)
• Antitubercular drugs
• Antileprosy drugs
• Antineoplastic drugs
• Antibiotics

8. Vitamins

9. Definition
Vitamins are organic compounds that are
required in very small amount for normal
growth and proper nourishment of the body .
Without the supply of vitamins ,the
individual will develop nutritional deficiency
diseases.

10. Classification of Vitamins:
Depending on their solubility : -
• i) Water-soluble vitamins
• Vitamin B & C
• ii) Fat-soluble vitamins
• Vitamin A,D,E,K
• iii) Insoluble both in water and fat:
• Vitamin H (Biotin)

11. Classification of Vitamin B complex
Vitamins Chemical Name
Vitamin B1 Thiamine
Vitamin B2 Riboflavin
Vitamin B3 Niacin
Vitamin B5 Panthotenic acid
Vitamin B6 Pyridoxine and pyridoxamine
Vitamin B7 Biotin
Vitamin B9 Folic acid
Vitamin B12 Cyanocobalamin
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12. Hormones
• They are regulatory substances secreted by the endocrine glands or ductless
glands and directly poured into the blood streams.
• They are required in very small concentrations for controlling and regulating
metabolism , growth and reproduction.
• Classification:
• Thyroid Hormones & Antithyroid Hormones
• Pituitary Hormones & Hypothalamic Hormones
• Pancreatic Hormones & Hypoglycaemic agents
• Sex Hormones
• Adrenal Cortex Hormones

13. Nomenclature of drugs
• Drugs may have three or more names
• i) Chemical Name or systematic name
• Ii) Generic or Common name
• Iii) Proprietary or brand or trade name

14. Chemical Name or systematic name
• It should describe the chemical structure of the drug
• It is given according to the rules of nomenclature of chemical
compounds
This Photo by Unknown Author is licensed
under CC BY-SA
Acetyl salicylic acid

15. Generic or Common name
This name refers to the common established name by which a drug
is known as an isolated substance irrespective of its manufacture.
It should be simple ,concise & meaningful
For example : Aspirin is a common name of Acetyl salicylic acid

16. Proprietary or brand or trade name
• This is the individual name selected & used by manufacturers.
• It should be catchy, short &easy to remember.
• For example :
This Photo by Unknown Author is licensed
under CC BY-SA
Chemical Name Generic
name
brand name
Acetyl salicylic acid Aspirin Dispirin ,Ecosprin

17. Some medical terms
1. Pharmacon : Drug
2. Phramacophore : The particular functional groups or structural
units of a drug which causes the physiological effect is called the
phramacophore
3. Prodrug:
• A biologically active drug which by latentiation is converted into an
inactive carrier form is called prodrug
• Application of prodrug:
• prolongation of action, shortening of action & drug localisation.

18. Some important medical terms
• 𝐿𝐷50- The Median Lethal Dose
• 𝐸𝐷50- The Median Effective Dose
• 𝐺𝐼50 : Growth Inhibition of 50% of cell
• Therapeutic Index:
• T.I. =
𝐿𝐷50
𝐸𝐷50

19. 𝐿𝐷50- The Median Lethal Dose:
This is the dose expressed in mg/kg, which would be expected to kill one-
half of test population of the same species & strain of bacteria. The
minimum dose to cause death of 50% of the test population is called 𝐿𝐷50
𝐸𝐷50- The Median Effective Dose :
This is the dose expressed in mg/kg, which produces a desired response in
50% of the test population. This method involves the treatment of a group
of patients with several doses in increasing amounts of standard
preparation. Then the minimum concentration required to have positive
response from 50% of the population is determined.

20. 𝐺𝐼50 : Growth Inhibition of 50% of cell :It is the concentration of the drug to
cause 50% reduction in proliferation (growth)of cancer cells .
Therapeutic Index: It is an approximate assessment of the safety of the drug &
is expressed as the ratio of the median lethal dose to the median effective
dose.
T.I. =
𝐿𝐷50
𝐸𝐷50

21. Brief idea of following terms
Receptor: It is the portion of the molecule or structure with which the
therapeutically active compound interacts producing series of events leading
to an observable response.
Agonist: It is a chemical or a drug that binds to a receptor & activates the
receptor to produce a biological response.
Antagonist : It is a chemical that binds to a receptor & blocks a biological
response.

22. Drug –Receptor Interaction
Drug action is due to the binding of drug to the receptor site. The drug binding
is due to ionic or non ionic forces.
Non-ionic binding is due to hydrogen bonding, hydrophobic bonding, & vander
Walls forces
The interaction involves formation of drug –receptor complex & resultant
response or effect.
D + R = DR  E

23. Drug Potency: Drug Potency can be defined as the maximum biological
action which can be caused by a minimum amount of the drug
administered .
Bioavailability : It is defined as the percentage of the biologically active drug
which is absorbed from a given dosage form and reaches the systematic
circulation in the body following the administration of the drug.
Drug Toxicity: Drug administration always followed by the expected
reactions considered to be toxic reactions. This may range from a mild skin
rash to more serious complications.

24. Spurious Drugs:
• A drug shall be deemed to be spurious
1. If it is imported under a name which belongs to another drug. Or
2. If it is an imitation of , or is a substitute for another drug or resembles another
drug in a manner likely to deceive or bears upon it or upon its label or
container the name of another drug. Or
3. If the label or container bears the name of the name of an individual or
company purporting to be the manufacturer of the drug, which individual or
company is fictitious or does not exit. Or
4. If it has been substituted wholly or in parts by another drug or substance Or
5. If purports to be the product of manufacturer of whom it is not truly a
product.

25. Misbranded Drug
A drug shall be deemed to be Misbranded Drug
1. If it is so coloured ,powdered or polished that damage is concealed OR
2. If it is made to appear better or of greater therapeutic value than really is OR
3. If it is not labelled in a prescribed manner OR
4. If its label or container or anything accompanying the drug bears any
statement, design or device which makes any false or misleading claim for the
drug.

26. Adulterated Drug
• A drug shall be deemed to be Adulterated :
• If it consists ,in whole or in part of any filthy ,putrid or decomposed
substance. OR
• If it has been prepared ,packed or stored in under unsanitary conditions OR
• If its container is composed in whole or in parts of any poisonous or
harmful substance OR
• If it contains any harmful or toxic substance OR
• If it bears or contains , a colour which is not approved OR
• If the drug has been mixed with any other substance so as to reduce its
strength or quality.

27. Pharmacopoeia
• It is a book of directions & requirement for the preparation of
medicine .It is generally published by an authority.
• Thus pharmacopoeia is a legislation of a country which sets standards
& obligatory quality indices for drugs ,raw materials and various
pharmaceutical preparations.
• British pharmacopoeia (B.P.)
• United states pharmacopoeia (U.S.P.)
• Indian pharmacopoeia (I.P.)

28. Chapter 1.2
Routes of Drug Administration & dosage form
Dose is the appropriate amount of drug is needed to
produce a certain degree of response in a patient
The dose of a drug depends on the response which is desired
Analgesic dose of aspirin for head ache is 0.3 to 0.6 gm, while its
anti-inflammatory dose is 3 to 6g/day

29. Factors governing the choice of route
Physical & chemical properties of a drug
Site of desired action
Rate & absorption of a drug from various routes
Effect of digestive juices on drug metabolism
Rapidity with which the response is desired
Accuracy of dosage desired
Condition of the patient

30. Different routes of drug administration
Oral Route (Mouth Cavity)
Parental Route
Topical Route
Subcutaneous route
Nasal Route
Rectal Route

31. Parenteral route of drug
administration
Advantages
1.1) Action is faster & definite (suitable for emergencies)
2) Gastric irritation & vomiting are not provoked
3) Can be employed even in unconscious ,uncooperative &vomiting patient
4) No chance of interference by food or digestive juices & liver
Administration by injection
which takes the drug directly
into tissue fluid or blood
strem without having cross to
the intestinal mucosa

32. Disadvantages of Parenteral route
Preparation has to be sterile
It is costlier
Technique is invasive & painful &assistance is required
Chances of local tissue injury & is risky at times.

33. Oral route of administration
It is safer, more convenient & does not require assistance
It is painless & medication need not be sterile
It is economical ,both solid & liquid dosage form can be
given orally
Advantages
The drug (liquid
/solid) is placed in
mouth cavity.

34. Disadvantages of Oral route of administration
The onset of action is slow,therefore not suitable during emergencies
Irritant & unpalatable drug can not be administered by this route
The route may not be useful in presence of vomiting & diarrhoea
Can not be used for uncooperative & unconscious patient
Certain drugs may not be absorbed by this route .* streptomycin

35. The end
Reference : Drugs and Dyes textbook .Himalaya publication