INDUSTRIAL PHARMACY A SCIENTIFIC REVIEW REPORT ON "EVALUATION OF AEROSOLS"Unlocking the Mysteries of Aerosols: Delve into the Pioneering Insights of Industrial Pharmacy in Our Scientific Review Report – A Journey through the Evaluation of Aerosols."

1. BIRBHUM PHARMACY SCHOOL
BANDHERSOLE, BIRBHUM, WB 731124
Continuous Assessment (CA-2), 2023
A SCIENTIFIC REVIEW REPORT
ON
“
EVALUATION OF AEROSOLS”
Submitted by
NAME: SOUVIK BHATTACHARYYA
ROLL NO: 35301921003
REG NO: 213530201910010 (2021-22)
COURSE: B. PHARM
STREAM - PHARMACEUTICAL TECHNOLOGY (PHARMACY)
SUBJECT: INDUSTRIAL PHARMACY (THEORY)
PAPER CODE: PT-515
YEAR: 3rd
SEMESTER: 5th
DATE OF SUBMISSION- 29/08/23

2. Scientific Report on,
EVALUATION OF AEROSOLS.
Souvik Bhattacharyya*
B.PHARM. Birbhum Phanmacy School. W.B,731124
ABSTRACT
The technology of pharmaceutical aerosols has rapidly developed in the recent few years. Inhalational
therapeutics have offered various advantages over other conventional drugs with other routes of
administration. However, health concerns as well as ecological limitations have been reported and hence
encouraged the researchers in the field of pharmaceutical industry to search for other enhanced alternatives.
Aerosols are the pressurized systems, which act by releasing either continuous or metered dose of fine mist
spray after a proper activation of its valve system. An aerosol is a suspension of liquid or solid particles in a
gas, with particle diameters in the range of 10−9 to 10−4 m. An aerosol is a suspension of fine solid particles
or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols
are fog or mist, dust, forest exudates, and geyser steam. Traditionally, most aerosols container are made from
steel, which is then coated in tin to stop rusting or reacting to the contents. This mixture of steel and tin is
called tinplate. The tinplate is wrapped into a cylinder and then has a top and bottom welded on to keep it leak
proof. Pharmaceutical aerosols are dosage forms that deliver medication to the respiratory system. The types
are
Metered-Dose Inhalers (MDIs): Deliver a fixed dose of medication in propellant-driven sprays.
Dry Powder Inhalers (DPIs): Dispense medication in powder form, activated by the user's inhalation.
Nebulizers: Convert liquid medication into fine aerosol droplets, suitable for inhalation.
Pressurized MDIs (pMDIs): Contain drug suspension in a propellant for lung delivery.
Soft Mist Inhalers (SMIs): Generate a slow-moving aerosol cloud from a propellant-free solution.
These aerosols provide targeted treatment for respiratory diseases like asthma and COPD, ensuring efficient
drug delivery to affected areas in the lungs.
Keywords - Inhalational therapeutics, COPD, Pressurized, Anthropogenic, Geyser

3. 1
INTRODUCTION
Pharmaceutical aerosols represent a sophisticated class of drug delivery systems designed to administer
medications directly to the respiratory system. These aerosols offer a specialized approach to treating various
respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), and other lung-related
ailments. By harnessing the principles of aerosol science, pharmaceutical aerosols ensure that therapeutic
agents are finely dispersed as particles or droplets within a carrier medium, facilitating their efficient and
targeted delivery to the lungs.
The diverse landscape of pharmaceutical aerosols encompasses several distinct types of inhalation devices,
each tailored to meet the unique needs of patients and the specific characteristics of the prescribed medication.
These devices include Metered-Dose Inhalers (MDIs), Dry Powder Inhalers (DPIs), nebulizers, Pressurized
MDIs (pMDIs), and Soft Mist Inhalers (SMIs). Each type offers its own advantages, such as portability, ease
of use, or suitability for patients with varying degrees of lung function.The primary objective of
pharmaceutical aerosols is to ensure that medications directly reach the respiratory tract, where their
therapeutic effects are most needed. This localized delivery minimizes systemic side effects and optimizes the
drug's efficacy by targeting the source of the ailment. Achieving this precision requires careful consideration
of factors such as particle size, inhalation technique, and the properties of the drug formulation. In this context,
it becomes crucial for healthcare professionals to guide patients in selecting the appropriate aerosol device
and provide comprehensive training on correct usage. Likewise, pharmaceutical manufacturers continually
innovate to enhance the design and functionality of aerosol delivery systems, aiming to improve patient
compliance and overall treatment outcomes. This exploration into pharmaceutical aerosols delves into the
intricate realm of respiratory drug delivery, shedding light on the technological advancements and
collaborative efforts that strive to provide patients with effective and manageable solutions for respiratory
conditions.
Fig.1- Pharmaceutical Aerosol

4. 2
 CLASSIFICATION OF AEROSOLS:
Pharmaceutical aerosols can be classified based on several criteria, including the type of propellant, the
intended use, and the mechanism of action. Here are some common classification categories for
pharmaceutical aerosols:
 Based on Propellant Type:
Hydrofluoroalkane (HFA) Propellants: These are the modern replacement for CFC propellants due to
their lower impact on the ozone layer. HFAs are commonly used in many current aerosol medications.
Compressed Gas Propellants: Some pharmaceutical aerosols use compressed gases such as nitrogen or
carbon dioxide as propellants. These are typically used for products that do not require suspending the
drug in a liquid propellant.
 Based on Intended Use:
 Bronchodilators: Aerosols containing bronchodilator medications like albuterol or salbutamol are used
to relieve symptoms of asthma and other respiratory conditions by opening up the airways.
 Corticosteroids: These aerosols contain anti-inflammatory corticosteroid medications like
beclomethasone or fluticasone. They are used for long-term management of chronic respiratory conditions.
 Combination Products: Some aerosols combine both bronchodilators and corticosteroids in a single
formulation to provide both quick relief and long-term control of respiratory symptoms.
 Anticholinergic: Aerosols containing anticholinergic medications like ipratropium bromide are used to
relax airway muscles and improve airflow in conditions like COPD.
 Mucolytics and Expectorants: Aerosols containing medications like acetylcysteine help thin mucus and
promote its clearance from the respiratory tract.
 Local Anesthetics: Aerosols containing local anesthetics like lidocaine
can be used to provide temporary relief from sore throats or irritated
airways.
 Based on Mechanism of Action:
Fig:2- Pharmaceutical Inhaler
Metered-Dose Inhalers (MDIs): These aerosol devices deliver a specific and consistent dose of medication
with each actuation. They are commonly used for bronchodilators and corticosteroids.
 Dry Powder Inhalers (DPIs): These devices deliver medication in powdered form, relying on the patient's
inhalation to disperse the powder into the airways. They do not require propellants.
 Soft Mist Inhalers (SMIs): These are newer devices that deliver a slow-moving, soft mist of medication,
suitable for patients who have difficulty using traditional MDIs.

5. 3
 Nebulizers: While not aerosol containers in the traditional sense, nebulizers also create an aerosolized
mist of medication using compressed air or ultrasonic vibrations. They are often used for patients who
have difficulty using inhalers.
 MACHANISM OF AEROSOL:
The mechanism of pharmaceutical aerosols involves the controlled release of medication in the form of tiny
particles or droplets suspended in a gas. This allows for targeted delivery of drugs to specific areas of the
body, such as the respiratory system. The primary components involved in the mechanism of pharmaceutical
aerosols include the canister, the valve, the formulation (medication and propellant), and the patient's
inhalation process. Here's an overview of the mechanism:
 Canister: The pharmaceutical aerosol container, also known as the canister, holds the medication
formulation and the propellant. It is typically pressurized to ensure proper dispensing of the medication.
 Valve: The metering valve is a crucial component of the aerosol system. It controls the release of the
medication by opening and closing as the patient activates the inhaler. The valve regulates the flow of
propellant and medication, ensuring consistent dosing with each actuation.
 Formulation: The medication formulation is a mixture of the active pharmaceutical ingredient (API) and
a propellant. The propellant is a liquefied gas that creates pressure within the canister, allowing the
medication to be released when the valve is opened. Common propellants include hydrofluoroalkanes
(HFAs) and compressed gases.
 Patient Inhalation Process:
Activation: When the patient depresses the inhaler's actuator (the part that is pressed down to release the
medication), the metering valve opens, and the propellant is released.
Medication Release: As the propellant is released, it carries the medication with it. The pressure difference
between the canister and the environment causes the propellant to expand rapidly, forcing the medication
through the valve.
Atomization: The medication is forced through a small nozzle within the valve, breaking it into tiny particles
or droplets. These particles become suspended in the propellant gas, forming an aerosol mist.
Inhalation: The patient simultaneously inhales while activating the inhaler. This inhalation creates a flow of
air that draws the aerosol mist into the patient's airways.
Deposition: The inhaled aerosol travels through the respiratory tract, with the fine particles depositing on the
bronchial walls and alveoli in the lungs. The targeted deposition ensures efficient absorption and rapid onset
of action.

6. 4
The mechanism of pharmaceutical aerosols offers several advantages, including
accurate dosing, rapid drug delivery, and targeted action. However, successful
use of aerosols requires proper coordination between actuation and inhalation,
which can sometimes be challenging for certain patients. Ongoing research and
development continue to improve aerosol technologies, enhancing ease of use
and optimizing therapeutic outcomes for individuals with respiratory conditions
and other medical ne
 PHARMACEUTICAL AEROSOL CONTAINER:
A pharmaceutical aerosol container is a specialized packaging system designed to dispense medications
in the form of fine mist or particles suspended in a gas. This innovative technology enables efficient and
targeted delivery of drugs to the respiratory system, making it particularly effective for treating conditions
like asthma, chronic obstructive pulmonary disease (COPD), and other respiratory ailments.These
containers consist of a pressurized canister that holds the medication formulation, a metering valve, and a
propellant. The propellant, usually a liquefied gas,creates Fig.3:Pulmonari Delivery Mechanism Of Inhalation
pressure within the canister, allowing the medication to be released in a controlled manner when the valve
is activated. As the valve is depressed, a precise dose of the medication is propelled through the valve and
atomized into tiny particles. These particles are suspended in the propellant gas, forming a fine aerosol
mist that can be easily inhaled into the lungs through the use of a mouthpiece or a mask. Pharmaceutical
aerosol containers offer several advantages. They provide accurate dosing, ensuring patients receive the
prescribed amount of medication with each use. The fine particles produced by the aerosol enable efficient
drug absorption in the lungs, leading to rapid onset of action. This targeted delivery minimizes systemic
side effects and maximizes therapeutic benefits. Additionally, aerosol containers are portable, user-
friendly, and discreet, enhancing patient adherence to treatment regimens.However, challenges exist in
terms of coordinating the patient's inhalation with the actuation of the device and the proper cleaning and
maintenance of the equipment. Nevertheless, ongoing research and technological advancements continue
to refine pharmaceutical aerosol containers, enhancing their usability, reliability, and overall impact on
respiratory health management.
Fig.4:- Parts of Aerosol Container

7. 5
 EVALUATION OF PHARMACEUTICAL AEROSOLS:
Evaluating pharmaceutical aerosols involves assessing various factors to ensure their safety, efficacy, and
quality. Pharmaceutical aerosols are used
for inhalation therapy and require careful testing to ensure proper delivery of the active pharmaceutical
ingredient (API) to the respiratory system. The evaluation of pharmaceutical is proceed in mainly two types
1.Quality Control. 2.Stability Studies.
 Quality Control: Quality control tests are the most important test to evaluat the pharmaceutical
aerosols Quality control tests on aerosol products include the testing of all components and product
performance as explained below.
(a) Propellant: The identity of propellant is determined by gas chromatography or IR (infrared)
spectrophotometry. The purity and acceptability of the propellant should be checked by determination of
moisture, halogen, and non-volatile residue.
(b) Valves, actuators and dip tubes: These aerosol parts are subjected to physical and chemical inspection
to determine magnitude of valve delivery and degree of uniformity between individual valves. From each
batch 25 valves are selected and placed in suitable containers. The containers are filled with specific test
solutions. A button actuator with 0.02 inch orifice is attached to the valves. The filled containers are placed in
a suitable atmosphere at a temperature of 25±1°C. When the products have attained the temperature of 25±1°C,
the filled containers are actuated to fullest extent for at least 2 seconds. This procedure is repeated for 2
deliveries each from 25 test units. The individual delivery weights in milligrams are divided by the specific
gravity of the test solution to obtain the valve delivery per actuation expressed in L.
(c) Containers: Containers are examined for defects in the lining in terms of degree of conductivity of electric
current as a measure of the exposed metal. Glass containers must be examined for flaws. The dimensions of
the neck and other parts must be checked to verify conformity to specifications.
(d) Weight checking: Weight checking is done by periodically adding tare empty aerosol container to filling
lines, which after filling with concentrate, are removed and weighed. The same procedure is used for checking
the weight of the propellants. The unit of this test is expressed as pounds.
(e) Performance: Performance of aerosol product is tested by valve discharge rate. Contents of the aerosol
product of known weight are discharged for specific period of time. The container is reweighed after the time
limit and change in the weight per time dispensed gives the discharge rate in g/sec.
(f) Dose uniformity over entire contents: The delivered or emitted dose is the total amount of drug emitted
from the inhaler device and available to the user. Dosage Unit Sampling Apparatus for MDIs has REU Marion
specifically for the sampling and testing of Metered Dose Inhalers. Unless otherwise directed in the individual
monograph, the drug content of the minimum delivered doses (minimum number of sprays per nostril as

8. 6
described on the label, or instructions for use) collected at the beginning of unit life (after priming as described
on the label, or instructions for use) and at the label claim number of metered sprays from each of 10 separate
containers, must meet the following acceptance criteria: not more than 2 of the 20 doses are outside the range
of +20% of label claim, and none are outside the range of +25% as per label claim, while the mean for each
of the beginning and end doses falls within the range of +15% of label claim.
(g) Total number of discharges per container: According to USP-NF, this test is performed only on topical
aerosols of solution or suspension fitted with dose-metering valves. The number of discharges or deliveries is
determined by counting the number of priming discharges plus those used in defining the spray contents, and
continue to fire until the number of discharges as per label claim. The requirements are met if all the containers
or inhalers tested contain not less than the number of discharges stated on the label.
(h) Leak testing: It is a means of checking crimping of the valve and detecting the defective containers due
to leakage. It is done by measuring and comparing the Crimp's dimension. Final testing of valve closure is
done by passing the filled containers through water bath. Twelve aerosol containers (topical
solution/suspension aerosols) are selected and each container is weighed (W). Containers are allowed to stand
in an upright position at a temperature of 25+2°C for not less than 3 days, and again weighed (W). The time,
T during which the containers were under test, is determined in hours and the leakage rate is calculated in mg
per year, of each container taken by the formula: Leakage rate (mg/year)=(24/7) x (W₁-W₂) × (365) The
requirements are met if the average leakage rate per year for the 12 containers is not more than 3.5% of the
net fill weight, and none of the containers leaks more than 5% of the net fill weight per year.
(i) Spray pattern: This is done to check any defects in valves and spray pattern. It serves to clear the dip tube
of pure propellant and pure concentrate. Many pharmaceutical aerosols are 100% spray tested. Determination
of spray patterns involves the impingement of sprays on a piece of paper, which has been treated with dye-
tale mixture. The particles that strike the paper cause the dye to go into solution and to be absorbed onto the
paper. It gives a record of the spray pattern.
(j) Flame projection: The aerosol product is sprayed to an open flame for 4 seconds and the extension of the
flame is measured with the help of a ruler. Flame Projection is expressed as cm.
(k) Flash point: Tag Open Cup (TOC) apparatus is the standard apparatus for this test. The aerosol product
is chilled to a temperature of about-25°F and transferred to the test apparatus. The temperature of the test
liquid is increased slowly and the temperature at which the vapours ignite, is taken as the flash point, expressed
in °C.
(l) Vapour pressure: The vapour pressure is determined by pressure gauge. Variation in pressure indicates
the presence of air in head-space. A can punctuating device is also available for accurate measurement of
vapour pressure. The unit of this test is expressed as psig.

9. 7
(m) Density: The density is generally expressed as g/mL and deter- mined by hydrometer or a pycnometer.
(n) Moisture content: Moisture content is determined by Karl Fischer or gas chromatography method and
expressed as %.
(o) Net contents: The tared cans, placed onto the filling line are reweighed, and the difference in weight gives
the amount of contents present in the container. The unit of this test is expressed as pounds.
(p) Foam stability: The life of a foam ranges from a few seconds for quick breaking foam to one hour or
more depending on the formulation. Foam stability of an aerosol product can be determined by visual
evaluation: (i) time for a given mass to penetrate the foam, (ii) time for a given rod that is inserted into the
foam to fall, and (iii) rotational viscometer.
(q) Particle size distribuion: Particle size (expressed as um) is determined using Cascade Impactor and Light
Scattering Decay methods.
(r) Therapeutic activity: For inhalation aerosols, the determi- nation of therapeutic activity depends on the
particle size. For topical aerosols, therapeutic activity is determined by applying the therapeutically active
ingredients topically to the test areas and the amount of therapeutically active substances absorbed is
determined.
(s) Toxicity study: The topically administered aerosols are checked for chilling effect or irritation in the skin.
When the aerosol is topically applied, thermistor probe attached to the recording thermometer is used to
determine the change in skin temperature over a given period of time. REDM For inhalation acosols, toxicity
study is done by exposing test animals to ALQUADC vapours spA from the aerosol container.
(t) Mean delivered dose: The amount of drug substance per actuation is determined. Limits of +15% of the
label claim are acceptable.
(u) Microbial contamination: The total viable aerobic bacterial count in Inhalation Powders shall not be
more than 100 CFU (colony forming units) per g of the powder.Following tests are conducted specially for
topical aerosols: pressure, minimum fill, number of discharges per container, delivered-dose and dose
uniformity.Following tests are conducted specially for inhalation aerosols:uniformity of content, uniformity
of delivered dose, and number of deliveries.
 STABILITY STUDIES:
(a) Containers: Aerosol products are subject to
two types of stability testing: (i) electrochemical
testing, and (ii) long term static testing. Fig.5: Quality controlled test
Electrochemical testing provides a limited amount of information but is an effective screening tool. Long term
static testing provides the most significant information such as: weight loss, concentrate/propellant saturation

10. 8
changes (vapour pressure measurement), any change in spray characteristic, corrosion, and concentrate
stability (separation, coagulation, chemical change.colour and odour change). Long term static testing is
normally done at a temperature of 120°F for a period of 3 to 12 months.
Concentrate Stability testing is usually run in glass containers to rule out the possibility of the container
contributing to formula's instability. Product and Container Stability testing is conducted in the packaged and
sealed aerosol can.
(b) Concentrate and Propellant Stability : It is a good practice to prepare an adequate number of samples
so that at least one sample can be tested every week for the first three months, then tested every month
depending upon the time allotted for stability testing. Weekly tests should be made at ambient temperatures.
Testing will involve: (a) weight loss, (b) pressure testing. (c)
spray rate and spray pattern, (d) evacuation of net weight, (e)
concentrate colour and odour, and open aerosol container and
evaluate for corrosion and dip tube condition Low Temperature
Stability directions such as "protect from freezing" need to be
added to the product label if the product is not freeze-thaw stable.
Fig.6: stability studies
 ADVATAGES OF PHARMACEUTICAL AEROSOL:
Pharmaceutical aerosols offer several advantages as a drug delivery system, particularly for respiratory
medications and localized treatments. Some of the key advantages include:
 Targeted Delivery: Aerosols are designed to deliver medication directly to the site of action, such as the
lungs in the case of respiratory medications. This targeted delivery minimizes systemic exposure, reducing
the risk of unwanted side effects in other parts of the body.
 Rapid Onset of Action: Aerosol particles are typically fine and easily absorbed by the body. This leads
to a quick onset of action, making aerosols especially effective for providing rapid relief in conditions like
asthma attacks.
 Precise Dosing: Aerosol formulations are engineered to deliver consistent and precise doses with each
actuation. This accuracy helps ensure that patients receive the correct amount of medication, enhancing
treatment effectiveness.

11. 9
 Reduced Systemic Side Effects: By delivering medication directly to the site of need, aerosols can
minimize systemic absorption. This reduces the risk of systemic side effects that might occur with oral
medications.
 Portable and Convenient: Aerosol devices are usually small and portable, making them easy for patients
to carry and use on-the-go. This convenience encourages better adherence to treatment regimens.
 Discreet Administration: Aerosol devices are often discreet and can be used without drawing attention,
which can be important for individuals who need to take medications in public settings.
 Minimized First-Pass Metabolism: When drugs are taken orally, they often pass through the liver before
entering the systemic circulation. This can result in a reduction in drug concentration due to metabolism.
Aerosols bypass the digestive system and liver, reducing the impact of first-pass metabolism.
 Localized Treatments: Aerosols can be designed to deliver medications to specific areas, such as the
respiratory tract or the oral cavity. This is particularly useful for treating conditions that require localized
treatment, like asthma, COPD, and sore throats.
 Improved Inhalation Technique: For inhalable medications, patients need to inhale deeply to effectively
administer the medication. This practice can improve lung function and patient awareness of their
breathing.
 Variety of Inhalation Devices: Aerosols come in various forms, including metered-dose inhalers (MDIs),
dry powder inhalers (DPIs), and soft mist inhalers (SMIs), catering to different patient preferences and
needs.
 Pediatric and Geriatric Use: Aerosol devices can be adapted for use by children and the elderly, who
may have difficulty swallowing pills or using other forms of medication.
 Emergency Treatment: Aerosols can provide quick relief during acute medical situations, such as severe
asthma attacks, where prompt intervention is essential. While pharmaceutical aerosols offer many
advantages, proper instruction and education on correct usage are essential to ensure patients receive the
maximum benefit from these devices.
 DISADVANTAGE OF PHARMACEUTICAL AEROSOL
While pharmaceutical aerosols offer numerous advantages, they also come with certain disadvantages and
challenges. Some of the notable disadvantages include:
 Coordination Difficulty: Using aerosol inhalers requires coordination between pressing the canister and
inhaling deeply. Some patients, particularly children, elderly individuals, and those with certain physical
or cognitive impairments, may find it challenging to coordinate these actions correctly.
 Propellant Sensitivity: Some individuals may be sensitive or allergic to the propellants used in aerosols,
which could lead to adverse reactions like skin irritation or respiratory discomfort.

12. 10
 Environmental Impact: Traditional aerosol propellants, such as chlorofluorocarbons (CFCs), were
harmful to the ozone layer. While newer propellants like hydrofluoroalkanes (HFAs) are less harmful,
environmental concerns are still relevant.
 Device Maintenance: Aerosol inhalers require regular cleaning and maintenance to ensure proper
functioning. Neglecting maintenance could result in inconsistent dosing or device malfunction.
 Device Availability and Cost: Depending on geographic location and healthcare systems, certain aerosol
devices or formulations might not be readily available or affordable for all patients.
 Deposition Variability: Achieving consistent deposition of aerosol particles within the respiratory tract
can be challenging due to variations in inhalation technique, lung anatomy, and disease severity.
 Spacer Use: While spacers (aerosol extension devices) can help improve drug delivery by reducing the
need for precise coordination, not all patients may use them consistently.
 Residue and Taste: Some patients may experience an unpleasant taste or sensation after inhaling aerosols.
This residue can affect the mouth and throat, leading to issues like thrush or an aversion to using the device.
 Limited Formulations: Not all medications can be formulated for aerosol delivery. Some drugs may not
be stable in aerosol form or may not effectively produce the desired therapeutic effect through inhalation.
 Local Irritation: Inhaled medications can sometimes cause local irritation in the respiratory tract, leading
to symptoms like coughing or throat irritation.
 Patient Compliance: Ensuring consistent and proper use of aerosol inhalers can be challenging. Poor
adherence to prescribed regimens may lead to inadequate treatment outcomes.
To mitigate these disadvantages, healthcare professionals play a crucial role in educating patients about proper
device usage, addressing concerns, and offering alternative treatment options when necessary.

13. 11
CONCLUSION
The pharmaceutical aerosols Several types of therapeutic aerosol delivery systems, including pMDI, DPI,
nebulizer, the solution mist inhaler, and nasal sprays, are widely used. Both oral and nasal inhalation routes
are used for the delivery of therapeutic aerosols. Nasal inhalation is used for nasal sprays to deposit in the
nasal cavity, whereas oral inhalation is used for other delivery systems to maximize deposition in the
tracheobronchial and alveolar regions. Several methods have been used to estimate the dose to the respiratory
tract for pharmaceutical aerosol. FPF obtained from the in vitro test of particle size generally correlated with
lung deposition fraction obtained from in vivo data but did not predict the correct deposition fraction. Aerosol
deposition mechanisms in the human respiratory tract have been well studied. Prediction of pharmaceutical
aerosol deposition using established lung deposition models has limited success primarily because they
underestimated oropharyngeal deposition. Recent studies using realistic upper airway replicas and CFD
simulation improved our understanding of aerosol transport and deposition process in the oropharyngeal
regions. These studies prove that deposition by the impinging turbulent jet from the narrow diameter of the
DPI mouthpiece is the main mechanism for the enhanced deposition in the oropharyngeal region. For pMDI
devices, a high-speed jet from the nozzle is responsible for high deposition in the oropharyngeal region. Nasal
spray devices producing droplets >40 μm would be deposited completely in the nasal cavity following the
conventional lung deposition model. Materials penetrating the nasal valve available for deposition in the
turbinate region are desirable. Studies using gamma scintigraphy and nasal airway replicas showed that there
were minimal effects of droplet size, inspiratory flow, and device type on the deposition pattern. Both plume
angle and administration angle were found to be the critical parameters in determining deposition efficiency.
In thes report I discuss the various types of the evaluation method of the pharmaceutical aerosols and describes
the test which is used to evaluate the pharmaceutical aerosols.

14. 12
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