🏆 Top results in the quiz 'IP Topic Wise Test'
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🖊 20 questions
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🥇 vivek – 15
🥈 Sakshi Awasthi – 14
🥉 Omkar – 14

🔴 DEFINITION

Aerosol =

It is a disperse system that functions on the power of a compressed or liquefied gas to expel the contents from the container.

🔴 DEFINITION

Propellant =

It is the component of the aerosol system which develop pressure within the container and expel the product.

🔴 DEFINITION

Boyle's law =

For a given mass of a gas at constant temperature (T) the pressure (P) is inversely proportional to the volume.

🔴 DEFINITION

Actuator =

It is the component of the aerosol system which is used to opening the valve and producing required type of discharge.

🔴DEFINITION

Liquefaction =

It is the process of converting of gases into liquid.

🔴 CLASSIFICATION

Propellants used in Pharmaceutical Aerosols:

🔺1. Chlorofluorocarbons (CFCs)

Trichloromonofluoromethane
Dichlorodifluoromethane
Dichlorotetrafluoroethane

🔺2. Hydrochlorofluorocarbons
(HCFCs)

Difluoroethane
Hydrofluorocarbons (HFCs)
Tetrafluoroethane
Heptafluoropropane

🔺3.Hydrocarbons (HCs)

Butane
Isobutane
Propane
Hydrocarbon Ethers (HEs)
Dimethyl ether

🔺4.Compressed gases (CGs)

Carbon dioxide
Nitrous oxide
Nitrogen

Aerosols

-The term aerosol is used to denote various systems ranging from those of a colloidal nature to systems consisting of pressurized packages.

-Aerosols have been defined as colloidal systems consisting of very finely subdivided liquid or solid particles dispersed in and surrounded by a gas.

-Originally, the term aerosol referred to liquid or solid particles having a specific size range, but this concept has fallen into disuse.

-The present-day definition refers to those products that depend upon the power of a liquefied or compressed gas to dispense the active ingredient(s) in a finely dispersed spray, foam, or semisolid.

-Topical pharmaceutical aerosols can be formulated as:
•spray
•foam
•semisolid
and can be used to deliver therapeutic agents topically to the skin surface, rectally, and vaginally.

-They consist of a liquid, emulsion, or semisolid concentrate and liquefied gas or compressed gas propellant.

-Many therapeutically active ingredients have been administered or applied to the body by means of the aerosol dosage form.

-In 1978, the use of certain chlorofluorocarbons (CFCs) was curtailed by the FDA, EPA, and CPSC. These restrictions ap- plied to the use of Propellants 11, 12, and 114 (CFCs) for use in all aerosol products.


MODE OF OPERATION

1. Liquefied-Gas Systems

-Liquefied gases have been used widely as propellants for most aerosol products.
-Types of system:
a. TWO-PHASE SYSTEM

-This is the simplest of all aerosol systems. It consists of a solution or a suspension of active ingredients in liquid propellant or a mixture of liquid propellant and solvent.

b. THREE-PHASE SYSTEM

-This system is useful for topical pharmaceutical aerosols in that it allows a greater use of liquid components not miscible with the propellants.

2. Compressed-Gas Aerosols

-Aerosols using compressed gases as the propellant are finding increased use. These propellants, especially nitrogen, carbon dioxide, and nitrous oxide, are acceptable for use with pharmaceuticals.

3. Barrier-Type Systems

-These systems separate the propellant from the product itself. The pressure on the outside of the barrier serves to push the contents from the container.

a. PISTON TYPE
b. PLASTIC-BAG AND BAG-IN-BAG
TYPE
c. CAN-IN-CAN SYSTEMS

PROPELLANTS

-The propellant generally is regarded as the heart of the aerosol package.

-In addition to supplying the necessary force to expel the product, the propellant must also act as a solvent and diluent and has much to do with determining the characteristics of the product as it leaves the container.

-Various chemical compounds have been used as aerosol propellants.

-Compounds useful as propellants can be classified as:


1. Liquefied gases
-Chlorofluorocarbons (CFC)
-Hydrochlorofluorocarbons (HCFC)
-Hydrofluorocarbons (HFC)
-Hydrocarbons (HC)
2. Hydrocarbon ethers
3. Compressed gases
-Nitrogen
-Nitrous oxide
-Carbon dioxide


CONTAINERS

•Metal
-TIN-PLATED STEEL
-ALUMINUM
-GLASS

PARTS OF CONTAINER:

•VALVES
-The primary purpose of the valve is to regulate the flow of product from the container.
-Continuous-Spray Valves
A small hole about 0.013 to 0.020􏰇 in diameter sometimes is placed in the valve body.

-Foam Valves
Valves for foam or aerated products usually have only one ex- pansion orifice, the one at the seat.

•ACTUATORS
-The actuator provides a rapid and convenient means for releasing the contents from a pressurized container. It provides the additional functional use in allowing the product to be dispensed in the desired form, that is, a fine mist, wet spray, foam, or solid stream.

•PACKAGING
-Depending on the nature of the product concentrate, the aerosol can be filled by a cold-filling or a pressure-filling process. There are advantages and disadvantages to both methods, and there are many factors that must be considered before deciding which process to use.

🗝

🔴Binding of drugs to receptors🔴

📌•Binding of drugs to receptors necessarily obeys the Law of Mass Action.

📌 •At equilibrium, receptor occupancy is related to drug concentration by the Hill–Langmuir equation

📌•The higher the affinity of the drug for the receptor, the lower the concentration at which it produces a given level of occupancy.

📌•The same principles apply when two or more drugs compete for the same receptors; each has the effect of reducing the apparent affinity for the other.