Lectures 04 Dosage forms, Doses of Drugs and Drug Administration

Workshop on Pharmacology of hearing and speech sciences

1. Session II
Dosage forms and doses of drugs.
Drug administration
Drugs in Pregnancy /Causing Disabilities in
Newborn

2. Dosage forms and
Doses of drugs.
Drug administration.
DR. GHULAM SAQULAIN
M.B.B.S., D.L.O., F.C.P.S
HEAD OF DEPARTMENT OF
ENT
CAPITAL HOSPITAL,
ISLAMABAD

3. Dosage Forms
Drug substances and crude drugs are developed
into drug dosage forms in order to optimize
stability, safety and effectiveness of drug
substances and to make them suitable for
administration.

4. CLASSIFICATION OF DRUG DOSAGE
FORMS
According to the consistence, they are classified
as:
1. Solid dosage forms
2. Liquid dosage forms
3. Semisolid dosage forms
4. Aerosols

5. SOLID DOSAGE FORMS
Solid dosage forms have many advantages
over other types:
greater stability,
less risk of chemical interaction between
different medicaments,
smaller bulk,
accurate dosage,
and ease of production.

6. Classification of Solid Dosage Forms:
1. Powders.
(Oldest form. Flexibility in compounding
and good chemical stability.
Unsuitability for dispensing, and
inaccuracy of dose)
1.Bulk Powders
2.Simple powders (one active
drug)
3.Complex powders
(Mixture)
2.Tablets
Tablets for oral administration
1.Buccal tablets
2.Sublingual tablets
3.Chewable tablets
4.Effervescent tablets
5.Sugar-coated tablets
6.Enteric coated tablets
7.Controlled-release tablets

7. Tablets for parenteral administration
Inserts – inserted into body
orifices
Pellets (tablets for implantation)
eg. Estradiol.
3. Capsules
Drug enclosed in container to mask
smell and taste
Hard gelatin capsules –DFC filled
with powder.
Soft gelatin capsules – round,
oval, oblong or tube shaped
contain paste, liquid or powder.
Enteric-coated capsule – remain
intact in the stomach.
4.Granulas –They are dosage forms
related to powders. Suitable for
preparation of solutions or mixtures of
drugs which are unstable in water
5. Pills – Small, round. The powdered
ingredients are mixed with binding
agents and solid extracts and made
into a plastic mass and rolled into
spheres coated with gelatin or sugar.
6. Troches (Lozenges) – Contain drug in
a flavoured base in discoid shape.

8. Classification of Liquid Dosage Forms:
1.Solutions
(Are homogenous mixtures of a solid, liquid or gas in a liquid solvent
Molecules of dissolved substance are dispersed among those of solvent)
Aqueous solutions – In sterile water
No aqueous solutions – In alcohol or hydro alcohol solution, ethereal or
glycerine solution.
2.Emulsions
(Two phase system in which one liquid is dispersed throughout another liquid in form
of droplets)
Oil in Water
Water in Oil
3.Suspensions
(Two phase system of finely divided solid dispersed in liquid)
4.Mucilages
(Are thick viscid adhesive liquids produced by dispersing gum in water
prevent immediate sedimentation of insoluble substance in liquids)

9. 1.Infusions and decoctions
Infusion is dilute solution of readily soluble constituents of crude drug
(from soft parts of plants)
Decoction are extracts of water soluble and heat stable constituents
from crude drug (from hard part of plants)
2.Drops
Solutions, tinctures or mixtures of high potent drug substances.
3.Mixtures
Multicomponent liquid containing two or more active ingredients
dissolved, suspended or dispersed in suitable liquid base.
4.Sterile dosage forms for injection
ampoules
vials
bottles
prefilled disposable syringes

10. Classification of Semisolid dosage forms:
Ointments
prepared for external application on skin and mucous
membranes
ointments – upto 25% solid active ingredient in
Oleaginous bases
creams –Emulsion bases
pastes –Contain large amount of solids
Gels
 Active ingredients are incorporated in water soluble
bases.
 And provide faster release of drug substance compared
to creams and ointments.
They have high deg. Of clarity
ease of application and removal.

11. Liniments
Are thick, viscid liquids, emulsions, suspensions intended for
external application.
Applied with friction and rubbing
Suppositories
Are solid forms of various weights and shapes for inertion
into rectum, vagina or urethra, where they melt and dissolve.
rectal suppositories
vaginal suppositories
urethral suppositories
Plasters
medicated plasters
transdermal delivery systems (TTS)

12. AEROSOLS (SPRAYS).
Designed to carry drug into the respiratory tree or
on skin and mucous membrane (nasal etc)
Three Groups:
Gases
Vapors of volatile Liquids
Aerosols
Aerosols contain finely subdivided liquid or solid
particles dispersed in a gas medium. The pressurized
aerosol packages contain different propellants
(gases) driving the drug to form mist or foam.

13. Drug Administration

16. Routes Of Administration:
There are 8 main routes of administration
Oral Administration (four types)
Liquids. 5 Types
Solution. Dissolution of small drug molecules in Water.
Syrup. Dissolution in sugar solution
Elixer. Active ingredient dissolved in a solution that contains 15 to
50% by volume of ethyl alcohol.
Suspension. Dissolution of larger molecules in water. Must be shaken
before use.
Emulsion. Dissolution in oil. Must be taken with juice due to
unpleasant taste.
Tablets. Has 6 main components
Drug (s)
Binder. Holds ingredients together
Disintegrator.
Lubricant
Other Ingredients. Make size convenient and appearance aesthetic
e.g., sugar, menthol and dye.

17. Coat. Gives the tablet other physico-chemical
characteristics than its ingredients itself.
Three types:
Sugar Coated. Provides better taste and prevents
dissolution before the tablet is swallowed
Enteric-Coated. Protects from dissolution in the
stomach and allows dissolution in the intestine.
Sustained Release-coated. Provides gradual release
and sustained absorption of drugs.
Capsules.
Enclosure of drugs in gelatin cases
Dissolve in the acidic part of the stomach

18. Powders. Must be dissolved in liquids.
Vaginal Administration
Used for treatment of local irritation and infection,
contraception, and /or hormone replacement.
6 Types:
Cream
Foam
Jelly
Ointment
Suppository
Tablet
Rectal Administration
Used if the patient is vomiting or not cooperating
(unconscious etc), if the drug is harmful for the gastric
mucosa or rapidly eliminated by the liver, and / or for
local treatment (eg., haemorrhoids).
Administered in the form of a suppository
Contains a vehicle (eg., butter, polyethylene glycol, or
glycerinated gelatine) that is solid at room temperature
but melts at body temperature.

19. Opthalmic Administration
Used for treatment of local infection and
inflammation, for treatment of glaucoma, and/ or
diagnostic purposes.
Three types:
Solution/ suspension
Administered by dropper bottles
Ointments
Administed by tubes
Polymer Reservoirs
Slow release system
Administered by patches placed on the
conjunctiva
Otic Administration
Used for treatment of local infection and inflammation
and/ or other disorders of the internal and external ear
Administered in the form of liquids

20. Nasal Administration
Used for treatment of nasal congestion and/ or mucosal
inflammation due to allergies
Administered in the form of liquids by droper or spray
Topical Administration
Used for the treatment of local bacteral/ fungal/ viral
infections, wounds, burns, rash and or dermatitits.
7 Types:
Emolients
Lotion
Ointments
Cream
Solution
Saop
Shampoo

21. Parenteral Administration
Injections and infusions
2 Categories
Medication for local effects (5 types)
Intraarterial
Intracardiac
Intradermal
Intraarticular
Intralesional
Medication for Systemic Effects (3Types)
Subcutaneous (SC)
Intramuscular (IM)
Intravenous (IV)

22. Doses of Drugs
1.Dose
2.Minimum dose
3.Maximum dose
4.Daily dose
5.Total dose
6.Single dose
7.Loading dose
8.Maintenance dose
9.Median lethal dose
10.Median effective dose
11.Therapeutic index
12.Toxic dose & fatal dose

23. A drug dose is the specific amount of medication to be
taken at a given time.
Drug DoseDrug Dose

24. The MED is then defined as the lowest dose level of a
pharmaceutical product that provides a clinically
significant response in average efficacy

25. An effective dose (ED) is the dose or amount of drug
that produces a therapeutic response or desired
effect in some fraction of the subjects taking it.
Effective DoseEffective Dose

26.  The largest quantity of a drug that an adult can
safely take within a given period.
Maximal DoseMaximal Dose

27. The total amount of a drug that is to be taken
within 24 hours.
Defined daily dose (DDD)
This is a pharmacoeconomic term for the average
maintenance dose for the clinical indication of a
drug in adult patient. The Defined daily doses
(DDDs) are a WHO (The World Health Organization)
statistical measure of drug consumption.
Daily DoseDaily Dose

28. The sum of all individual doses which may be
received over a period of time.
Total DoseTotal Dose

29. Single dose of drug to be taken in a day
For example.
Dosage: Adults and children should take one ml
for every 5kg of body weight. This should be taken
as a single dose after food.
Single DoseSingle Dose

30. A large initial dose of a substance or series of such
doses given to rapidly achieve a therapeutic
concentration in the body
Maintenance dose
The amount of drug required to keep a desired
mean steady-state concentration in the tissues.
Loading DoseLoading Dose

31. Median lethal dose or mean lethal dose.
 The amount of a drug or other substance that, when
administered to a group of experimental animals, will kill 50
per cent of the group in a specified time
Median effective dose
It is defined as the dose producing a response that is 50
percent of the maximum obtainable.

32. The amount of a drug or other agent that if
administered to an animal or human will prove fatal
Lethal DoseLethal Dose