lesson - 31 pharmaceutical aerosols i
TRANSCRIPT
Lesson - 31
Pharmaceutical Aerosols I
-Dr Ajay Semalty
Department of Pharmaceutical Sciences,
H.N.B Garhwal University (A Central University)
Srinagar Garhwal-246174
Learning outcomes
After learning this module you will be able to understand
• Basic principle of Aerosol
• Advantages, Limitation of aerosol
• Uses of aerosol
Lesson Plan
• Aerosol: Definition
• Advantages,
• Limitation
• Uses of aerosol
Aerosols
You know it very well, but you just don’t know that it is aerosol. Can you
guess? We use/see it almost daily. Not necessarily for medical use. E.g.
Module 31 Pharmaceutical Aerosols I
2 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Deospray, perfume spray, Mosquito/cockroach repellant spray. Yes they are
aerosols.
The beautiful rainbow is the best example from the nature. It is a quite stable
liquid aerosol. On the other hand, Irrigation fountain is the example of coarse
unstable liquid aerosol.
Pharmaceutical aerosols
Aerosols are being used from decades for therapeutic purpose globally. E.g.
pressurized metered dose inhalers (MDIs), dry powder inhalers (DPIs),
nebulizers, skin sprays (pain killer spray) etc. Ever increasing incidence of
asthma globally is increasing the demand of aerosols.
The technology’s continual advancement, the ease of use and the more
desirable pulmonary-rather-than-needle delivery for systemic drugs has
increased the attraction for the pharmaceutical aerosol in recent years.
Moreover, the increasing incidence of asthma at an average rate of 5 % per
year in developed as well as developing countries is creating a consistently
high demand of inhalers or MDIs (about 50 to 60 million patients are relying
on MDIs).
Definition
Module 31 Pharmaceutical Aerosols I
3 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
The word aerosol means: “Aero= air, Sol = solution”. Aerosol is a
“Pressurized package”.
“Aerosols are a suspension of small solid particles or droplets suspended
in a gas or vapor.”
“Aerosols are the products that depend on the power of a compressed or
liquefied gas to expel the contents from the container.”
“Pharmaceutical aerosols are products that are packaged under pressure and
contain therapeutically active ingredients that are released upon activation of
an appropriate valve system. They are intended for topical application to the
skin as well as local application into the nose (nasal aerosols), mouth (lingual
aerosols), or lungs (inhalation aerosols). These products may be fitted with
valves enabling either continuous or metered-dose delivery; hence, the terms
“[DRUG] Metered Topical Aerosols,” “[DRUG] Metered Nasal Aerosols,”
etc.” [USP definition]
Learning the definition
Active drug dissolved, suspended or emulsified in propellant to
release drug in the form of mist, spray to topical, nasal, oral, pulmonary
and other body cavities for local and systemic therapeutic uses
Module 31 Pharmaceutical Aerosols I
4 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Advantages
Easy administration: The product is administered easily and quickly.
Portable: Aerosols are portable and tamper-proof.
Minimum dose required: Lower dose of drug can be used and hence
Minimize adverse and side effects A dose can be removed without
contamination of materials.
Direct delivery of drug to target area: The medication can be
delivered directly to the affected area
Better spreading due to spray/ mist type of delivery: Drug is
delivered in a desired form, such as spray, steam, quick breaking foam
or stable foam, Application of medication in thin layer.
Quick onset of action: Drug acts quickly due to direct delivery at
affected area and that to in spray form.
Lower irritation: Irritation produced by the mechanical application of
topical medication is reduced or eliminated.
Module 31 Pharmaceutical Aerosols I
5 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Dose to dose to maintenance of sterility: When sterility is an
important factor, it can be maintained while a dose is being dispensed.
Better protection for oxygen and or moisture sensitive drugs:
Stability is enhanced for these substances adversely affected by oxygen
and or moisture
Avoid first pass metabolism: Avoidance of degradation of the drug in
the GIT and first pass effect
Limitation
Not Cost effective (diclo spray v/s diclo tablet)
Proper use needed to get the effect. (prone to incorrect use)
Limited safety hazard
o Flammable
o Pressurized
o Inadvertent inhalation
Ancillary devices are required with an MDI (like holding chambers and
spacers )
Uses of Pharmaceutical Aerosols
Since decades, pharmaceutical aerosols have played an important role in
treating respiratory disorders like asthma and chronic obstructive pulmonary
disease (COPD), and MDIs and DPIs have become an important part of that
treatment. But the use of aerosol products are not limited to the pulmonary
Module 31 Pharmaceutical Aerosols I
6 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
route, these can be administered by various routes of administration (ROA)
for various therapeutic effects (Table 1). These can be administered by
topical, nasal, ocular, oral, rectal and vaginal routes also.
Oral and Lingual Aerosols
Easy access to hard-to-reach sites
Easy access to systemic circulation
Avoid FPM
Examples: Anti-anginals (e.g. Nitroglycerin) in emergency, Local
anesthetics (e.g. Lidocaine) for dental use, Antacids (e.g. Aluminum
and magnesium silicate), Antiseptics (e.g. Chloroseptic)
Module 31 Pharmaceutical Aerosols I
7 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Topical Aerosols
Convenient as compared to application
No need to touch skin
Unused product is not contaminated
Examples: Spray on bandages, Antifungal sprays (Miconazole),
Antibacterials(e.g. Neomycin), Wound washing, Rubiferants (e.g.
Methylsalicylate), Anti-inflammatory steroids (e.g. Dexamethasone),
Local anesthetics (e.g. Benzocaine)
Module 31 Pharmaceutical Aerosols I
8 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Vaginal Aerosols
• Easy access
• Expands to fill available space
• Provide complete surface coverage
• Example: Contraceptive Foams (e.g. Nonoxyenol-9)
Rectal Aerosols
• Easy access
• Expands to fill available space
Module 31 Pharmaceutical Aerosols I
9 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
• Provide complete surface coverage
• Example: Anti-inflammatory steroids (e.g. Hydrocortisone), Local
anesthetics (e.g. Pramoxine)
Nasal Aerosols
• Easy access
• Minimal dripping
• Example: Decongestants (e.g. Phenylephrine), Antiallergics (e.g.
Cromolyn sodium), Anti-inflammatory steroids (e.g. eclomethasone),
Antismoking (Nicotine), Moisturizers (e.g. Normal saline), Systemic
access of Antidiuretics (e.g. Desmopressin)
Module 31 Pharmaceutical Aerosols I
10 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Ocular Aerosols
• Easy access
• Minimal dripping
• Contact lens cleaning solutions (not applied directly to eye)
Respiratory Aerosols
• Local as well as systemic action is obtained
• E.g. Anti-inflammatory steroids (e.g. Beclomethasone), Antiallergics
(e.g. Cromolyn sodium), Antivirals (e.g. Ribavirin), Bronchodilators
Module 31 Pharmaceutical Aerosols I
11 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
(e.g. Albuterol), Migraine (e.g. Ergotamine tartrate), Smoking
cessation (e.g. Nicotine)
Take away Message
• Aerosols are pressurized package
• Drug is dissolved suspended or emulsified in propellant and dispensed
in the form of mist or spray for local or systemic action.
• These are used by various ROA like oral, rectal, vaginal, topical etc.
• Low dose, quick onset of action, high bioavailability, low adverse
effect, avoiding FPM are the main advantages
• Refer further reading links; take part in discussion forum.
• We will discuss the components of aerosol in the next module.
Further Readings
• Banker & Rhodes, Modern Pharmaceutics, CRC Press.
• Aulton ME (ED), Pharmaceutics: The science of Dosage form design,
II edn, Churchill Livingstone, London, 2002.
• Semalty et al., Essentials of Pharmaceutical Technology, II Edn.
Pharma Med press, Hyderabad, India
Module 31 Pharmaceutical Aerosols I
12 MOOC: Industrial Pharmacy-I by Dr Ajay Semalty (Course Coordinator), HNB Garhwal
University (A Central University) Srinagar (Garhwal) Uttarakhand, India
Credits/References
• USP
• Semalty et al., Essentials of Pharmaceutical Technology, II Edn.
Pharma Med press, Hyderabad, India, ISBN 9789386819994