Dosage Forms and Drug Delivery Systems

Pharmaceutical Dosage Forms
&
Drug Delivery
Dr. Shivankan Kakkar, MD

COMPETENCY- The student should be able to:
Demonstrate understanding of the use of various dosage forms
(oral/local/parenteral; solid/liquid)
NATIONAL MEDICAL COMMISSION
(N.M.C.)
M.B.B.S. UNDERGRADUATE
CURRICULUM Vol. I
PHARMACOLOGY (CODE: PH)
NUMBER –PH2.1

Specific Learning Objectives
At the end of the practical class, the student shall be able to:
• Identify different dosage forms used in pharmaceuticals.
• Describe the key routes of administration for various dosage
forms.
• Compare and contrast the advantages and disadvantages of a
given dosage form.
• Evaluate the appropriateness of a specific dosage form for a
particular drug and patient population based on its merits and
demerits.
• Formulate accurate instructions for patients on the proper use
of a specific dosage form, considering factors like timing,
administration technique, and special considerations.
Clincal Pharmacology by DrShivMD 3

Dose Vs Dosage
• A dose refers to a specified amount of
medication taken at one time.
• By contrast, the dosage is how to take the
medication as prescribed:
- a specific amount,
- number, and
- frequency of doses over a specific period of
time.

Dose Vs Dosage
• Drug doses are expressed in metric mass units
(for example, milligrams or milligrams per
kilogram.)
• A dosage will be expressed in the same units,
but over a specific time period—for example,
"500 milligrams every six hourly for three
days”

Dosage Forms
• Dosage forms are the means ( or the form ) by which
drug molecules are delivered to sites of action
within the body.
• The need for dosage forms:
1. Accurate dosing delivery.
2. Protection via coatings and sealed ampoules.
3. Masking taste and odor.
4. Precise drug placement in body tissues.
5. Sustained release for prolonged action.
6. Optimizing drug efficacy.
7. Drug insertion into body cavities (rectal, vaginal).

Label of a Given Dosage Form
• Name and dose of the drugs
• Batch No
• Manufacturing and expiry date
• Maximum retail price(MRP)
• Schedule of the drugs i.e. H, P, X etc.
• Instruction about use of drugs
• Address of the pharmaceutical company

• Various types of drug dosage forms are prepared
to enhance drug delivery to various body tissues
under different clinical conditions.
• Depending on route of administration, they are
classified as
• Enteral
• Parenteral
• Inhalational
• External

Enteral Dosage
Forms
Oral Liquids
Suspensions
and Emulsions
Solutions Aqueous
Alcoholic
Solids
Capsules
Tablets
Powders
Rectal
Solids Suppositories
Liquids Enema

•ID Dosage Forms: Name the
dosage form in the photo.
•Routes: Describe the
administration route.
•Pros & Cons: Contrast advantages
and disadvantages.
•Usage Guidance: Formulate
patient instructions.

Syrups
– Advantages:
• Mask Bad Taste: Sweet taste helps mask unpleasant
taste of drugs, making it suitable for children.
• Quick Action: Faster effect compared to tablets
requiring disintegration.
– Disadvantages:
• Maintenance: Requires careful maintenance.
• Cost: Costlier than tablets.
– Effective Use Instruction: Take the prescribed syrup
amount orally, then securely close the bottle.

I. ENTERAL DOSAGE FORMS
A. Oral
1. Liquids
A. Solutions
1. Aqueous Solutions
i. Syrup: sweetened aqueous solution
of drug e.g. cough syrups. This is the
most common aqueous solution for
oral administration.
ii. Other less common aqueous
solutions of drugs include:
• Water: aqueous solution of volatile oil e.g. peppermint
water.
• Aqueous extract: 100% concentrated drug extract in water
e.g. ergot extract
• Infusion: aqueous solution obtained by soaking dried plants
in hot or coldwater.

•ID Dosage Forms: Name the dosage form in the photo.
•Routes: Describe the administration route.
•Pros & Cons: Contrast advantages and disadvantages.
•Usage Guidance: Formulate patient instructions.

A. Oral
1. Liquids
A. Solutions
2. Alcoholic Solutions
i. Elixir: sweetened hydroalcoholic
solution of drug e.g. phenobarbital
elixir.
ii. Other less common alcoholic
solutions of drugs include:
• Spirit: alcoholic solution of volatile oil e.g. peppermint
spirit.
• Tincture: hydroalcoholic solutions of non-volatile
substances (10-20% alcohol) e.g. tincture belladonna.
• Fluid extracts: concentrated tinctures; each 1 ml contains
the therapeutic ingredients of 1 g of crude drug e.g.
cascara.

Elixirs
– Advantages:
• Improved Compliance: Pleasant flavor and color
enhance patient compliance, especially for potent
or nauseous drugs.
– Disadvantages:
• Maintenance: Requires careful maintenance.
• Cost: Costlier than tablets.
– Effective Use Instruction: Take the prescribed
elixir amount orally, then securely close the bottle.

Suspensions
– Advantages:
• Chemical Stability: More chemically stable than
syrups.
• Masking Properties: Masks taste and odor of drugs.
• Versatile Administration: Allows insoluble solids to be
administered in liquid form.
– Disadvantages:
• Microbial Contamination: Requires a suitable
preservative.
– Effective Use Instruction: Shake the bottle before use,
then take the prescribed suspension amount orally.

and disadvantages.

Emulsions
– Advantages:
• Oily Drug Administration: Suitable for oily drugs.
• Rapid Absorption: Finely dispersed oil is quickly
absorbed.
• Masking Properties: Emulsifying agents mask taste
and smell.
– Disadvantages:
• Microbial Contamination: Requires a suitable
preservative.
– Effective Use Instruction: Shake the bottle well before
use, then take the prescribed emulsion amount orally.

A. Oral
1. Liquids
B. Suspensions & Emulsions
Suspensions: insoluble solids suspended in water e.g.
antibacterial oral suspension (cefuroxime) and
antacid oral suspension (alumina, magnesia,
simethicone).
Emulsions: insoluble liquids suspended in water, as oils
suspended in water, with addition of an emulsifying
agent as gum e.g. simethicone emulsion and castor oil
emulsion .

A. Oral
2. Solids
A. Tablets
•Ordinary tablet: A small disc of medicated compressed powder
mixed with inert binder as starch or lactose.
•Caplet: A smooth, coated, oval-shaped tablet. Many caplets have an
indentation running down the middle so they may be split in half
easier. e.g., acetaminophen caplet.
•Coated tablet: A sugar coat protects the drug & masks its bad taste.
•Delayed release tablet: Does not release the drug immediately after
administration, e.g. Enteric-coated tablet (aspirin), in which the coat
dissolves in the intestine to avoid gastric irritation or inactivation.
•Extended release tablet: With different coats and different
disintegration times to give rapid onset & long duration of action,
thus allows reduction in dosing frequency, e.g., metformin extended
release tablets.

•Pros & Cons: Contrast
advantages and disadvantages.

Sublingual Tablets
– Advantages:
• Drug does not get destroyed in stomach.
• Poor absorption from stomach can be overcome.
• Liver can be bypassed and quick onset of action.
– Disadvantages:
• Can produce ulcers in mouth and other systemic adverse
effects.
• One has to spit the drug after the desired effect is
achieved, to avoid side effects
– Correct instruction for effective use of this dosage form:
• Tablet is to be placed below the tongue.
• Patient has to spit out the taken drug after the desired
effect is achieved.

and disadvantages.

A. Oral
2. Solids
A. Tablets
•Orally disintegrating tablet (ODT): A friable tablet that dissolves
rapidly in the mouth. Also known as sublingual tablets e.g.,
ergotamine sublingual tablets.
•Lozenges: Flavored tablets that dissolve slowly in the mouth. A
lollipop is a lozenge on a stick.
•Chewable tablet: A tablet that is chewed to ensure complete
breaking up of the tablet and diffusion of the active ingredient. It
produces a pleasant tasting residue in the oral cavity that is easily
swallowed and does not leave a bitter or unpleasant aftertaste.
•Effervescent tablet: A tablet that contains mixtures of acids (e.g.,
citric acid, tartaric acid) and sodium bicarbonate, which release
carbon dioxide when dissolved in water. This is used to mask the
salty or bitter taste of drugs e.g., Vitamin C effervescent tablets.

A. Oral
2. Solids
B. Capsules
• A solid oral dosage form consisting of a shell and a filling.
• The shell is composed of a single sealed enclosure, or two
halves that fit together.
• Capsule shells may be made from gelatin, starch, or cellulose,
or other suitable materials, may be soft or hard, and are filled
with solid or liquid ingredients that can be poured or
squeezed.
• Usually hard gelatin capsule contains powder and soft gelatin
capsule contains liquids.

and disadvantages.

A. Oral
2. Solids
B. Capsules
 Extended release capsule: also known as spansule or sustained-
release capsule e.g., dextroamphetamine spansule.
 Delayed release capsules: such as enteric-coated capsule to
avoid gastric irritation e.g., esomeprazole delayed release
capsules.
Pills
 Prior to the widespread use of the machine-compressed tablet,
pills were very popular products that usually were prepared by a
pharmacist as spherical masses of medical substances.
 Now "pills" is used by the public to refer to variants of tablets
and capsules.

and disadvantages.

A. Oral
2. Solids
C. Powders
Powder forms of drugs
May be dispensed in small paper packets.
May be formulated as effervescent granules.
Effervescence
Is due to CO2 release.
Masks the salty or bitter taste of drugs.
e.g., urinary alkaliniser effervescent powder.

and disadvantages.

B. Rectal
1. Liquids (Enema)
Evacuating Enemas
Warm water (600 mL) given rapidly under high pressure.
Intended to evacuate the lower GIT.
Retention Enemas
Warm water (100 mL) given slowly by drip under low
pressure.
To administer drug through rectum (e.g., corticosteroid in
ulcerative colitis).
Precautions before Retention Enemas
Rectum is first cleaned with evacuant enema.
Amount must not exceed 200 mL & level of solution
must not be high.
Drug solution should not be irritant.

and disadvantages.

B. Rectal
2. Solids (Suppository)
Drug is incorporated in a waxy base.
Glycerine suppositories
To evacuate the lower GIT.
Medicated suppositories
To administer drugs through rectum (e.g., aminophylline).

Parenteral
Dosage
Forms
Liquids
(Injections)
Ampoules
Vials
Prefilled
Syringe
Solids
(Implants)
Pellets

and disadvantages.

II. PARENTERAL DOSAGE FORMS
A. Liquids (Injections)
Ampoules
A single dose of sterile solution or suspension.
Vials
A multi-dose preparation. Unstable drugs are prepared as
vials to which the solvent is added before use.
Pre-filled syringe
For drugs requiring accurate dosing, e.g. enoxaprin.
B. Solids (Implants)
Pellets

Inhalational
Dosage
Forms
Gases
Vapours
Steam Inhalation
Aerosols Nebulizers
Metered-Dose Inhalers
Powders
Spinhalers
Aerolizers
Turbuhalers
Diskus

III. INHALATION DOSAGE FORMS
• A. Gases: Oxygen, some general anesthetics.
• B. Vapours: Highly-volatile liquids: e.g., amyl nitrite & diethyl
ether.
• C. Steam Inhalation: drugs vaporized by steaming e.g., tinct.
benzoin inhalation.
• D. Aerosols
Aerosols are suspensions of a liquid or solid in a gas
administered through:
I. Nebulizers
II. Metered-Dose Inhalers (MDI)

• Choosing the Appropriate Oxygen Mask and Flow Rate:
– Check patient's target oxygen saturations (usually 94-98%, or
88-92% for those at risk of type 2 respiratory failure).
– Select oxygen mask and flow rate based on clinical situation.
• Oxygen Delivery Devices and Approximate Flow Rates:
• Nasal Cannulae:
– Flow rate: 2-4 L/min (mild hypoxaemia, low-flow oxygen)
– Approximate percentages of oxygen delivered:
• 1L/min - 24%
• 2L/min - 28%
• 3L/min - 32%
• 4L/min - 36%

• Simple Face Mask:
– Flow rate: 5-10 L/min
– Maximum FiO2: 40%-60% at 15 L/min
– Not recommended below 5 L/min
• Reservoir Mask (Non-Rebreather Mask):
– Flow rate: 10-15 L/min
– Oxygen concentrations: 60% - 90%
– Suitable for trauma/emergencies, oxygen concentration varies
• Venturi Masks:
– Accurate oxygen concentration regardless of flow rate
– Available concentrations: 24%, 28%, 35%, 40%, 60%
– Suitable for patients needing specific oxygen concentrations
– 24% and 28% for those at risk of carbon dioxide retention

• Hypoxaemia:
– PaO2 < 10 kPa (75 mmHg) on air
• Severe Hypoxaemia and Respiratory Failure:
– PaO2 < 8 kPa (60 mmHg) on air
– In type 2 respiratory failure, PaCO2 > 6.0 kPa (45 mmHg)
• Piped Oxygen System and Flow Meter:
– Flow meter attached to oxygen wall port.
– Flow meter uses a ball to indicate oxygen flow rate.
• Steps to adjust flow rate:
– Connect oxygen tubing to flow meter outlet.
– Turn valve to start oxygen flow, ball rises to show flow rate.
– Adjust valve for desired flow rate (ball in the middle).

A flow meter attached to an
oxygen wall port.

The ball of the flow meter
should be positioned in the
middle of the line of the
desired flow rate.
This example shows a flow
rate of 10 l/min.

and disadvantages.

D. Aerosols
I. Nebulizers
- It depends on the suction created by a jet of air (or Oxygen)
to spray the drug.
- Amount of drug delivered is limited only by toxicity of drug.
- The drug is dissolved in a low boiling point liquid in a canister
under pressure.
- Pressing the top of the canister opens a valve releasing a
metered-dose of liquid which evaporates leaving an aerosol of
the drug to be inhaled.

D. Aerosols
Advantages
Portable and compact and available for most substances.
Disadvantages
1. Difficult to use as it requires coordination between
activation of canister, inspiration & a final holding of
breath. This problem can be overcome by the use of a
Spacer.
2. Depends on the presence of a propellant substance
added to the contents of the inhaler. Thus the amount
of the drug delivered is limited by toxicity of drug as
well as the additives in inhaler.

and disadvantages.

E. Powders
• Powders are administered through dry-powder inhalers (DPI),
e.g. Spinhalers: e.g. sodium cromoglycate.
- The drug is formulated as a micronized powder.
- Suitable for patients who fail to use metered-dose inhalers.
- May cause transient bronchoconstriction.
• Other examples of DPI include: Aerolizer, Turbuhaler and
Diskus

1. Spinhaler:
– Mechanism: Patient's inhalation effort punctures a capsule containing powdered
medication, releasing it for inhalation.
– Inhalation Effort: Requires a strong and coordinated inhalation effort.
– Age: An older type of DPI.
2. Aerolizer:
– Mechanism: Patient's inhalation effort triggers the release of dry powder from a
capsule.
– Inhalation Effort: Requires patient's inhalation effort to create airflow for medication
dispersion.
– Features: Provides consistent dosing and ease of use.
3. Turbohaler:
– Mechanism: A reservoir of powdered medication, patient twists the base to release a
dose.
– Inhalation Effort: Requires less inhalation force compared to some other DPIs.
– Features: Dose counter, designed for ease of use.
4. Diskus:
– Mechanism: Disk-shaped device with doses in blisters, patient slides lever to expose a
dose.
– Inhalation Effort: Requires patient's inhalation to automatically release medication.
– Features: User-friendly design, consistent dose delivery.

External Dosage
Forms
Skin and Mucous
Membrane
Liquids
Semiliquids
Semisolids
Solids
Vaginal Dosage Forms
Solids (Pessary)
Liquids (Douche)

and disadvantages.

IV. EXTERNAL DOSAGE FORMS
A. Skin & Mucous Membranes
1. Liquids
a. Lotion: aqueous solution for local application.
b. Liniment: alcoholic solution for local application.
c. Astringents: substances with vasoconstrictor & protein
denaturing effect.
d. Antiseptics: substances used topically to kill microorganisms
(too toxic for systemic use).

1. Liquids
e. Emollients (moisturizers):
Emollients soften & smoothen skin surface by occluding it
with an oily film making it impervious to water. This prevents
normal water loss from skin surface & leads to a build-up of
moisture in stratum corneum.
f. Drops for ear, nose and eye.

2. Semiliquid
a. Cream: emulsion of oil in water incorporates the drug e.g.
corticosteroids, antibiotics and antifungal drugs.
b. Gel: contains a gelling agent to provide stiffness to a solution
or a colloidal dispersion.
c. Ointment: the ointment base (Vaseline or lanoline)
incorporates the drug e.g. corticosteroids, NSAIDs and
antibiotics.
- Ointments are used for dry lesions, creams for semi-wet
lesions & lotions for wet lesions

3. Semisolid
a. Paste: mixture of powder + ointment.
b. Patches: A patch impregnated with the drug, e.g.
nitroglycerin patch.
4. Solid: Powder, e.g. antifungal powder.

and disadvantages.

B. Vaginal Dosage Forms
1. Liquids:
Douche
• Douche is a method of rinsing the vaginal canal with water or a solution,
but it's generally discouraged by healthcare professionals due to its
potential to disrupt the natural vaginal flora and cause irritation.
2. Solid:
Pessary
• Pessary is a drug that is inserted into the vagina to treat infections, e.g.,
antifungal pessary. Additionally, pessaries are medical devices placed
inside the vagina to provide support for conditions like pelvic organ
prolapse. They come in various shapes and sizes and are prescribed by
doctors to help manage specific gynecological issues.

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