Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmaceutics 2 > aerosols > Flashcards

aerosols Flashcards

1
Q

what is a dispersed system

A

undissolved or immiscible particles
(drug) distributed throughout a vehicle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the dispersed phase

A

The substance that is distributed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the dispersing phase\ dispersion medium

A

the vehicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are aerosols

A

are pressurized dosage forms that upon actuation emit a fine
dispersion of liquid and/or solid materials containing one or more active ingredients in a gaseous medium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how is the pressure applied in aerosols

A

through the use of one or more liquefied or gaseous
propellants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the physical statues of the propellant

A

liquefied gas or a
compressed gas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the physical form of the contents that are emitted through aerosols

A

a fine mist; a coarse, wet, or dry spray; a steady stream; or
a foam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

on what does the physical form depends on

A

► The physical form selected is based on the intended use.
► An aerosol used for inhalation therapy, as in the treatment
of asthma or emphysema, must present particles in the
form of a fine liquid mist or as finely divided solid particles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

is the particle size important for dermatologic sprays

A

it is coarser and generally less critical
to the therapeutic efficacy of the product.

Some dermatologic aerosols present the medication in the
form of a powder, a wet spray, a stream of liquid ,or an
ointment-like product.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

give examples on everyday use items that are aerosols

A

personal deodorant sprays, perfumes and
colognes, sprays, paint sprays, lubricants and a
number of pet products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the advantages of aerosols

A
  1. A portion of medication may be easily withdrawn from the
    package without contamination or exposure to the remaining
    material.
  2. By virtue of its hermetic character, the container protects
    medicinal agents adversely affected by atmospheric oxygen, light and moisture. it also keeps them steril.

3-Topical medication may be applied in a uniform
thin layer to the skin without anything else. which reduces irritation and also provide a cooling and refreshing effect.

4-the physical form and the particle size of the emitted
product may be controlled, which may contribute to the
efficacy of a drug, as with the fine controlled mist of an
inhalant aerosol.

  1. Aerosol application is a clean process, requiring
    little or no wash up by the user
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the two main parts of aerosols

A

product concentrate and propellant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the product concentrate

A

the active ingredient of the aerosol
combined with the required adjuncts, such as antioxidants,
surface active agents, and solvents, to prepare a stable and
efficacious product.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the role of liquefied propellants

A

it frequently serves the dual role of propellant and
solvent or vehicle for the product concentrate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what was the most common propellant and why did we stop using them

A

A chlorofluorocarbon (CFC) is an organic compound , They reduce the amount of ozone in the stratosphere,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

when can we use CFCs

A

(a) there are no technically feasible alternatives
to the use of a CFC propellant in the product.

b) the product provides a substantial health or
other public benefit unobtainable without the
use of the CFC.

(c) the use does not involve a significant release of CFCs
into the atmosphere or, if it does, the release is warranted
by the benefit conveyed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

give examples on CFCs

A

dichlorodifluoromethane dichlorotetrafluoroethane,
trichloromonofluoromethane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how can we liquefy a gas

A

by cooling and pressure For example, dichlorodifluoromethane will form a liquid when cooled to −30°C or when compressed to 70 psig (pounds per square inch gauge) at 21°C .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the advantage for using liquid propellants

A

Therefore the system has a constant vapor pressure as
long as it still contains a liquid phase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the types of gases used in the compressed gas propellants

A
  1. insoluble gases in liquid phase of aerosol;
    ► e.g., Nitrogen…. will result in emission of a product in
    essentially the same form as it was placed in the container.
    ►Nitrogen is odorless, tasteless and inert towards the other
    components of aerosol and protects the product from
    oxidation.
  2. Slightly soluble gases in liquid phase of aerosol…… These may be employed when their expulsion with the product concentrate is
    desired to achieve spraying or foaming
    ► E.g., Carbon dioxide and nitrous oxide.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the biggest difference between compressed gas and liquid gas aerosols

A

Unlike aerosols prepared with liquefied gas
propellant, compressed gas filled aerosols have no
reservoir of propellant. Thus higher gas pressures
are required in these systems, where the pressure
in these aerosols diminishes as the product is
used.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how can we control the pressure of an aerosol

A

(a) the type and amount of propellant and
(b) the nature and amount of product
concentrate.

23
Q

what is space sprays aerosols

A

► Space sprays generally contain a greater proportion of
propellant than do surface aerosols.
► Space aerosols usually operate at 30 to 40 psig at 21°C
and may contain as much as 85% propellant.

24
Q

what are surface aerosols and foam aerosols

A

Surface aerosols commonly contain 30% to 70% propellant
with pressures between 25 and 55 psig at 21°C.

• Foam aerosols usually operate between 35 and 55 psig at
21°C and may contain only 6% to 10% propellant,Foam aerosols may be considered to be emulsions, because the liquefied propellant is partially emulsified with the product concentrate rather than being dissolved in it.

25
Q

give an example for a reactive propellant

A

trichloromonofluoromethane forms
free hydrochloric acid when formulated with
systems containing water or ethyl alcohol,The hydrochloric acid affects the efficacy of the product and corrodes some container components.

26
Q

what are the possible side effects of propellants

A

► when an active ingredient ordinarily used in a nasal or oral spray is placed in a fine aerosol mist, it may reach deeper into the respiratory tract than desired and result in irritation.

► With new dermatologic, vaginal, and rectal aerosol products, the
influence of the aerosol form of the drug on the recipient tissue
membranes must be evaluated for irritating effects.

► The absorption pattern of a drug may change because of an increased rate of solubility of the fine particles usually produced in aerosol products.

► Although the fluorinated hydrocarbons have a relatively low order of toxicity and are generally nonirritating, certain individuals who use an inhalation aerosol may be sensitive to the propellant agent and may exhibit cardiotoxic effects following rapid and repeated use .

27
Q

what is the two phase aerosol system

A

The two-phase system aerosol consists of
the liquid phase, containing the liquefied
propellant and product concentrate, and the
vapor phase like sprays.

28
Q

whats the 3 phase aerosol system

A

Three-Phase System aerosol consists of a layer of
water-immiscible liquid propellant, a layer of highly
aqueous product concentrate, and the vapor
phase like emulsions (foam)

29
Q

what does the effectiveness of the aerosols depends on

A

the proper combination of formulation, container, and valve assembly.

30
Q

what are the properties of the formulation, container, and valve

A

► formulation must not chemically interact with the
container or valve components.

► The container and valve must be capable of
withstanding the pressure required by the product,
it must resist corrosion,

►the valve must contribute to the form of the product to be
emitted.

31
Q

what are the materials that the container can be made from

A

(a) glass, uncoated or plastic coated; (b) metal,
including tin-plated steel, aluminum, and stainless steel;
and (c) plastics.

32
Q

how do we choose the container

A

based on its adaptability to production methods,
compatibility with formulation components, ability to
sustain the pressure, the interest in design and cost.

33
Q

talk about glass containers

A

► They are chemically compatible with the formula than do metal
containers.
► They are not subject to corrosion.
► BUT:
► glass containers must be precisely engineered to provide the maximum in pressure safety and impact resistance.

►glass containers are quite safe when the
total pressure of an aerosol system is below
25 psig and no more than 50% propellant is
used required, the inner surface of glass
containers may be coated to render them
more chemically resistant to formulation
materials.

34
Q

talk about metal containers

A

►Tin-plated steel containers are the most
widely used metal containers for aerosols

► Aluminum containers are manufactured by extrusion or by
other methods that make them seamless.

► They have the advantage over the seam type of container
of greater safety against leakage, incompatibility.
Stainless steel is employed to produce containers
for certain small-volume aerosols in which a great deal of
chemical resistance is required.

• The main limitation of stainless steel containers
is their high cost.

35
Q

talk about metal containers

A

►Tin-plated steel containers are the most
widely used metal containers for aerosols

► Aluminum containers are manufactured by extrusion or by
other methods that make them seamless.

► They have the advantage over the seam type of container
of greater safety against leakage, incompatibility.
Stainless steel is employed to produce containers
for certain small-volume aerosols in which a great deal of
chemical resistance is required.

• The main limitation of stainless steel containers
is their high cost.

36
Q

talk about plastic containers

A

►Plastic containers have met with varying
success in the packaging of aerosols
because of their problem of being
permeated by the vapor within the
container.

Also, certain drug–plastic interactions affect
the release of drug from the container and
reduce the efficacy of the product.

37
Q

whats the valve’s function

A

to permit expulsion of the contents of the can in the desired form, at the desired rate, and in the proper amount.

The materials of valves must be inert to the
formulations and must be approved by the
FDA. e.g are plastic, rubber, aluminum, and
stainless steel.

38
Q

what are the parts of the valves

A

1- Actuator: The button the user presses to activate the
valve assembly for emission of the product. It permits easy
opening and closing of the valve.

► 2-Stem: Supports the actuator and delivers the
formulation in the proper form to the chamber of
the actuator.

► 3. Gasket: Placed snugly with the stem, prevents
leakage of the formulation when the valve is
closed.

► 4. Spring: Holds the gasket in place and is the
mechanism by which the actuator retracts when
pressure is released, returning the valve to the
closed position

5- Mounting cup: Attached to the aerosol
container, holds the valve in place. Its
underside is exposed to the formulation, it
must receive the same consideration as the
inner part of the container with respect to
meeting criteria of compatibility.
it may be coated with an inert material
(e.g., an epoxy resin or vinyl) to prevent an
undesired interaction

►6. Housing: below the mounting cup, it
links the dip tube and the stem and
actuator. With the stem, its orifice helps to
determine the delivery rate and the form in
which the product is emitted.

►7. Dip tube: Extends from the housing down
into the product; brings the formulation
from the container to the valve.

39
Q

what part of the valvue determines the physical form and particle size

A

The type and quantity of propellant used and the actuator
design and dimensions control the particle size of the
emitted product. The design of the inner chamber and size of the emission orifice of the actuator contribute to the physical form

40
Q

what are MDIs

A

A metered-dose inhaler (MDI) is a
device that delivers a specific amount of
medication to the lungs, in the form of a
short burst of aerosolized medicine.

41
Q

how do MDIs work

A

► They are employed when the formulation is a
potent medication, as in inhalation therapy.

► In metered valve systems, the amount of material
discharged is regulated by an auxiliary valve
chamber by virtue of its capacity or dimensions.

► A single depression of the actuator causes
evacuation of this chamber and delivery of its
contents.

42
Q

what are DPIs

A

A dry-powder inhaler (DPI) is a device that delivers
medication to the lungs in the form of a dry powder.
DPIs are commonly used to treat respiratory diseases
such as asthma, bronchitis, emphysema

43
Q

what are the DPIs proparties

A

 In DPI systems, drug is inhaled
As a cloud of fine particles.

 The drug is either:
 Preloaded in the device or
Filled into hard gelatin capsules or
 Filled in foil blister discs which
Are loaded into a device

Delivery of the respirable
dose depends on:
 Powder formulation.
 Inhalation Device.
 Patient’s inspiratory flow.

44
Q

what are the two filling ways of aerosols

A

► cooling below their boiling point
►or compressing the gas at room
temperature.

45
Q

talk about cold filling

A

both the product concentrate and the propellant must be cooled to−34.5°C to −40°C

The cooling system may be a mixture of dry ice and acetone or
refrigeration

• After the product concentrate has been quantitatively metered into a cold aerosol container, the liquefied gas is added.

• The heavy vapors of the cold liquid propellant displace the air in the container. some of the propellant vapors are also lost.

• When sufficient propellant has been added, the valve assembly is inserted and crimped into place.

46
Q

can aqueous systems be filled by cold filling

A

No, because the water turns to ice.
► For nonaqueous systems, some moisture
usually appears in the final product due to
the condensation of atmospheric moisture
within the cold containers.

47
Q

what are the advantages for pressure filling

A

There is less danger of moisture contamination of
the product
► Less propellant is lost in the process.

48
Q

When compressed gases are employed as the
propellant:

A

► The product concentrate is placed in the container, the
valve assembly is crimped into place, and the air is
evacuated from the container by a vacuum pump.

► The compressed gas is then passed into the container
through a pressure-reducing valve attached to the gas
cylinder.

► When the pressure in the aerosol container is equal to the
predetermined and regulated delivery pressure, the gas
flow stops and the aerosol valve is closed

49
Q

whats unique about aerosols

A

compared to other dosage forms is that the
product is actually packaged as part of the
manufacturing process.

50
Q

why do we use a cap in aerosols

A

This protects the valve against contamination with dust and dirt.

51
Q

abels must warn users not to puncture
pressurized containers, not to use or store
them near heat or an open flame.

A

ok

52
Q

talk about topical aerosols

A

► Convenient aerosol packages for use on the skin include
the anti-infective agents povidone iodine, tolnaftate, and
thimerosal.

► The preparation may be applied to the desired surface
area without the use of the fingertips, making the
procedure less messy than with most other types of topical
preparations.

► Among the disadvantages to the use of topical aerosols are
the difficulty in applying the medication to a small area and
the greater expense associated with the aerosol package.

53
Q

what are vaginal aerosols

A

► Aerosol foams containing estrogenic substances
and contraceptive agents are commercially
available.
► The foams are used intravaginally in the same
manner as for creams.
► ProctoFoam (Schwartz), contains pramoxine
hydrochloride is an example of commercial rectal
foams.

Pharmaceutics 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions