Introduction to Dosage Forms - Pharmaceutics - I B. Pharma 1st Semester

Introduction to Dosage Forms


• Introduction to dosage forms

• Classification of pharmaceutical dosage forms, definitions with examples. 

Learning Objectives

At the end of this lecture, student will be able to

Explain the importance of dosage forms

Define various dosage forms

Classify dosage forms with examples

Identify different solid dosage forms

Identify different liquid dosage forms

Define various dosage forms

Classify liquid dosage forms

Differentiate between syrups and elixirs

Differentiate between gargles and mouthwashes

Differentiate between suspensions and emulsions

Define various semi-solid dosage forms

Identify different semi-solid dosage forms

Differentiate between ointments and creams

Pure Drug

1. Un-palatable

2. Obnoxius taste, odour

3. Dirty colour

4. Difficult to handle


1. Drug - agent, intended for use in the diagnosis, mitigation, treatment, cure or prevention of disease in man or in animals

2. Excipients- additives are used to

-Give a particular shape

-To increase its efficacy

- To increase its stability

- For palatability 

- For elegance

3. Dosage form: Drug + Excipients


• Protection 

• Clarity

• Masking- taste/ smell

• Solubility

• Modify drug release

• For topical administration

• For insertion - body cavities.

• For introduction - blood stream/ body tissues.

• For inhalation

Classification (According to Physical State)


Unit Dosage Forms







Bulk Dosage Forms


- Effervescent Granules or Powders


- Dusting powder

- Insufflations

- Dentifrices

- Snuffs


1. Monophasic

• Internal

- Syrups

- Liniments

- Elixirs

- Pediatric drops

• External

- Lotions

- Linctus

- Gargles

- Mouthwash

- Throat paints

- Sprays

- Eye lotions

- Eye drops

- Nasal drops

- Douches

- Enemas

2. Biphasic

- Emulsions

- Suspensions








Classification (According to the route of administration)

1. Oral route

2. Topical route

3. Parenteral route

4. Rectal route

5. Nasal route

6. Ophthalmic /Ocular route

7. Vaginal route

8. Otic route

Solid Dosage Forms


• Solid unit dosage forms

• Compression or moulding methods.

Eg. Paracetamol tablets (Analgesic and Anti pyretic)

Tablet Compression Machine

Tablet Shapes

Types of Tablets

• Coated tablets

 -Film coated tablets

 -Sugar coated tablets

 -Enteric coated tablets

• Buccal & sublingual tablets: Buccal- cheek, Sublingual- Below the tongue


• Effervescent tablets: Before administration, dissolve in water effervescence. 

• Chewable tablet: To be chewed 


• Solid unit dosage forms - drugs - in a tasteless hard or soft soluble shell made of gelatin.

Hard Gelatin Capsule

Sizes of Hard gelatin capsules

• Sizes from 000 to 5

• 000 is the largest and 5 the smallest

Soft Gelatin Capsules


• Small, round - solid dosage forms


• Solid dosage forms- medicaments + flavored base

• They dissolve or disintegrate slowly in the mouth.


• Sugar-based lozenge on a stick 

• The lollipop provides almost immediate relief as the drug starts being absorbed in the mouth and starts to work within minutes

• Fentanyl Actiq (Cephalon) is a raspberry lollipop that contains Fentanyl citrate

• It has an off-white color

• Actiq is the first product specifically designed to aid in controlling breakthrough pain in cancer patients

• It is indicated only for the management of breakthrough cancer pain in patients with malignancies who are already taking and are tolerant to opioids. 


• Solid dosage forms - internal or external use

• Crystalline or amorphous forms


• Solid dosage forms

• Conical, bullet or ovoid shaped

• Insertion into the body cavities-such as rectum, vagina, urethra, nose and ears.

• Melt or dissolve in the cavity fluids




Types of Suppositories


• Solid dosage forms 

• Conical or ovoid in shape

• Insertion into the vagina

Dusting Powder

• Dusting powders - bulk powders

• External application to the skin.

• Mixtures of 2 or more than 2 ingredients. E.g. starch, talc, kaolin, zinc oxide etc.

• 2 types

i) Medical D.P

ii) Surgical D.P


• Finely divided powders

• Introduction into body cavities such as ears, nose, and tooth sockets

• Insufflator is used

Nebulizer and Inhaler

Dentifrices (Tooth Powder)

• Solid dosage forms

• Cleaning the surface of the teeth. 

• Applied with the help of fingers or a tooth brush.

• Contain an abrasive, detergent, sweeteners and colour. 


• Finely divided solid dosage forms

• Inhaled into the nostrils

• Antiseptic, bronchodilator and decongestant action.

Effervescent Powders/Granules

• Solid dosage forms

• Internal use

• Medicament + citric acid + tartaric acid + sodium bicarbonate.

• Before administration, the granules are dissolved in water-effervescence. 

E.g. ENO granules

Monophasic Liquid Dosage Forms for Internal use


• Sweet, viscous, saturated solution of sucrose

• The concentration of sugar is 66.7%w/w

• Vehicles- bitter drugs.

• Medicated syrups and Flavoured syrups

 E.g. Simple syrup, Ginger syrup, Orange syrup

• 66.7 % w/w: Self preservative, High osmotic pressure, Survival of microorganisms is difficult

Above 66.7 % w/w: Crystallization

Below 66.7 % w/w: Microbial contamination


• Clear, pleasantly flavoured, sweetened, hydroalcoholic 

• Potent drugs such as antibiotics, antihistaminics and sedatives.  

• Non-medicated elixirs- flavours and vehicles.

 E.g. Piperazine citrate elixir


• Viscous, liquid preparations

• Relief of cough.

• Demulcent, sedative or expectorant action.

• Linctuses should be taken in small doses, sipped and swallowed slowly

E.g. Codeine linctus

Paediatric Drops

• Liquid dosage forms.

• For pediatric patients

• Administration –with a dropper. 

E.g. Phenylephrine and Chlorpheniramine paediatric drops 

Monophasic Liquid Dosage Forms for External/Topical use


• Liquid or semi liquid preparations

• External application -skin.

• Applied to the skin with friction and rubbing of the skin.

• Should not be applied to the broken skin.

E.g. Camphor liniment


• Liquid preparations

• External application to the skin, without friction.

• Contain alcohol & glycerin

E.g. Body lotions

Monophasic Liquid Dosage Forms for use in the oral cavity


• Aqueous solutions 

• Pleasant taste and odour 

• Cleans and deodorises the buccal cavity.

• Should be diluted with water before use.

E.g Sodium Chloride mouthwash


• Aqueous solutions

• Relieve soreness in mild throat infections.

• Brought into close contact with the mucous membranes of the throat-retained for few seconds and spit out.

• Concentrated form - dilute with warm water before use. 

E.g. Potassium chlorate and phenol gargle 

Throat Paints

• Viscous liquid preparations

• Mouth and throat infections.

• Glycerin is used as the vehicle

• Applied with a brush.

• E.g. Mandl’s paint (Compound iodine paint)

Throat Spray

• Liquid preparations of drug 

• Vehicle may be water, alcohol or glycerin.

• Applied to the nose or throat with an atomiser or nebuliser (large droplets).

• E.g. Atropine spray

Monophasic Liquid Dosage Forms instilled/ used in body cavities

Nasal Drops

• Aqueous solutions

• Instilled into the nose with a dropper.

• Antiseptic, local analgesic and decongestant property.

• E.g. Oxymetazoline nasal drops (Nasivion) and Otrivin

Eye Drops

• Sterile aqueous or oily solutions

• Instillation into the eye.

• Sterile, isotonic, free from foreign particles.

• Glass containers (containing a glass dropper with a rubber teat) or plastic containers.

•Antiseptic, anaesthetic, anti-inflammatory, mydriatic or miotic

E.g Ciprofloxacin eye drops (antiseptic)

Eye Lotions

• Aqueous solutions

• Washing the eyes.

• Concentrated form - diluted with warm water immediately before use.

•Isotonic, free from foreign particles

E.g. Sodium Chloride eye lotion (antiseptic)


• Medicated solutions

• Rinsing body cavities such as nose, vagina or urinary bladder.




• Irrigations & Vaginal douches- sterile in nature

E.g. Potassium Permanganate vaginal douche


Procedure for administering Irrigations


• Aqueous / oily solutions / suspensions

• Introduction into the rectum

• Purgative, sedative, anthelmintic and anti-inflammatory effects.

•X-ray examination of the lower bowel.

E.g Barium sulphate enema

Barium Enemas

Biphasic Liquid Dosage Forms


•Biphasic heterogenous systems- 2 immiscible liquids

•2 immiscible liquids - water and oil.

• Mixed with each other by the addition of an emulsifying agent.

• Emulsions are of 2 types

• O/W and W/O

E.g Liquid paraffin emulsion (laxative)

• Common emulsions are mayonnaise, egg , milk


• Biphasic heterogenous systems

• Finely divided solid particles suspended or dispersed in a liquid vehicle.

• Oral administration: E.g Gelusil, Digene (antacids)

• External application: Calamine lotion (protective)

• Parenteral administration: Vaccines

• For biphasic preparations the labeling: “SHAKE WELL BEFORE USE” is mandatory

Semi Solid Dosage Forms


•Semisolid preparations

• External application to the skin and mucous membrane

• Greasy in nature

• Medicated ointments

• Ophthalmic ointments – eye - sterile and free from irritation.

E.g Neosporin ointment (Anti-bacterial)


• Semisolid preparations

• External application

• Less greasy/ not greasy when compared to ointments

E.g. Candid Cream (Anti- fungal)


• Semi- solid preparations

• Transparent or translucent

• Non greasy

• External application.

• Lubricating surgical gloves, rectal thermometers.

E.g. Hair styling gels, Toothpastes


• Semi solid preparations

• Solid content is more

• Non greasy

• External application.

E.g. Toothpastes

Other Dosage Forms


• Pressurized dosage forms of medicament

• Liquid droplets or solid drug particle is dissolved or suspended in a gas (which is called propellant).

• The different parts of an aerosol container are:

- Container

- Valve

- Actuator

- Dip tube.

Parts of an Aerosol Container

Uses of Aerosols

1) Topical use. E.g. Local anaesthetics, local analgesics, anti-inflammatory drugs. E.g. Iodex spray

2) Various body cavities. E.g. Nasal spray

3) Deodorants, perfumes, cosmetics, hair sprays, shaving lotions.

4) Disinfectant sprays, room fresheners and insect killers. E.g Baygon cockroach spray


• Paste like preparations

• Used externally to reduce inflammation because they retain heat well.

• Heated and spread thickly on a dressing and applied hot to the affected area. 


• Liquid or viscous preparations

• Application to the skin.

• Can be suspensions or emulsions.

E.g. Calamine and lime application (Lime- calcium hydroxide)


• Liquid oral preparation

• Taken as a single dose.

• Dispensed in small volumes.

E.g. Paraldehyde draught (sedative)   


• Liquid preparation for oral administration

• Medicament is dissolved or suspended in a suitable vehicle.

• Supplied only for a small number of doses

• Should be used within a short period.


• Solid unit dosage form

• Dry powder - enclosed in a shell

• Shell is rice flour + water - moulded and dried

• Wafer capsule. 

• For administering drugs with an unpleasant taste

• Large dose can be enclosed

• Before administration - immersed in water for a few seconds, placed on the tongue - swallowed with the help of water.


• Liquid preparation

• External application

• The vehicle is volatile and evaporates on application

• Leaves a flexible, protective film on site of application.

• Used for minor cuts and abrasions, corn removal etc.

E.g Salicylic acid collodion (Corn remover)


• Liquid preparations

• Contain volatile substances

• Used to relieve congestion and inflammation of the respiratory tract.

E.g. Eucalyptus oil - added to boiling water and the vapour is inhaled. 

• Effective in relieving nasal congestion.


1. Drug- Therapeutic action

2. Excipients – Non therapeutic ingredients 

3. Dosage form- Drug + Excipients

4. Classification of dosage forms

       - Physical state: Solid, Liquid, Semi-solid & Gaseous

       - Route of administration: Oral, Topical, Parenteral, Rectal, Vaginal, Nasal, Ophthalmic

5. Solid dosage forms: Tablets, Capsules, Pills, Suppositories, Pessaries and Powders

6. Tablets- Solid unit dosage forms prepared by compression or moulding methods.

7. Capsules- Solid unit dosage forms in which the drug is enclosed in a gelatin shell

8. Pills- Small, round - solid dosage forms

9. Suppositories- Solid dosage forms meant for insertion into the body cavities such as rectum, urethra, nose and ears

10. Pessaries- Solid dosage forms meant for insertion into the vagina

11. Powders- Solid dosage forms which are crystalline /amorphous forms

12. Liquid dosage forms- Monophasic and Biphasic

13. Differences between monophasic and biphasic preparations- One phase/ two phase

14. Monophasic liquid dosage forms- Internal use, external use, in oral cavity and in body cavities.

15. Biphasic liquid dosage forms- Emulsions and Suspensions

16. Emulsions – Liquid + liquid (Immiscible)

17. Suspensions – Insoluble solid + liquid

18. Ointments: Greasy preparations for external application

19. Creams: Less greasy preparations for external application 

20. Gels: Transparent or translucent preparations which are non-greasy and for external application 

21. Pastes: Preparations with high solid content nad are meant for external application

22. Aerosols: Pressurized packages containing a propellant

23.  Applications: Viscous preparations for external application

24. Draught: Liquid orals taken as a single dose 

25. Mixtures: Liquid orals supplied for small doses

26. Collodions: Volatile preparations for external application

27. Inhalations: Liquid preparations meant to be inhaled

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