First barrier encountered by particles

In the mucus barrier, drug particles in dry powder inhaler first dissolve in the mucus layer that contain ______ water.

Dissolution in the mucus is the rate limiting step for absorption of _______ water soluble drugs.

Dissolution in the mucus is the rate limiting step for absorption of water soluble drugs

Highly water soluble drugs may dissolve at the very high relative humidity in the airways

Once in solution, the drug diffuses through the mucus layer and enters the aqueous environment of the epithelial lining fluid

The rate of diffusion through the mucus depends on 3 things:

Self-cleansing mechanism of the respiratory system is part of which of the following barrier?

- Elimination of fluid, microbes and particulates from the respiratory tract due to ciliary function

- Removed from the respiratory tract within a few hours after being deposited

The particles deposited in the alveolar region may be engulfed by macrophages

The macrophages engulfed particles will be eliminated via the lymphatic system or absorbed into the pulmonary circulation

Aerosols are _______ dosage forms that emit a fine dispersion of liquid and/or solid materials containing one or more active ingredient in a gaseous medium

Aerosols requiere the same consideration with respect to formulation, stability and therapeutic efficacy. They depend on the functioning of the container and added component, the ________, to deliver the medication.

Aerosol formulation consist of 3 components

Components of aerosol formulation

You can commonly use propellants, chlorofluorocarbons (CFCs)

Instead of using propellants, hydrocarbons are the best option

Hydrocarbons are/have blends of butane, propane and isobutane. They have compressed air, _______, nitrous oxide.

The vapor pressure by both gases, Pt, is:

The vapor pressure required for a specific application can be calculated in a similar manner and different ratios of propellants may be used to obtain that pressure

Pressurized containers

Glass pressurized containers have good chemical compatibility and high pressure

Metal pressurized containers are of tin plated steel, aluminum, stainless steel and special coatings can be used

Plastics pressurized containers are impermeable to the vapor inside the container

Plastics pressurized containers have drug-plastic interactions

The function of the valve assembly is to permit the expulsion of the contents of the can in the desired form, at the desired rate, and, in the case of metered valves, in the proper amount or dose.

Among the materials used in the manufacture of the various valve parts are:

Aerosol container and valve

Pressurized Metered Dose Inhalers (pMDIs) allos administration of metered doses

In pressurized metered dose inhalers (pMDIs), drug is dispersed in propellants and the device facilitates aerosolization of the drug

Propane cannot be used as propellant

A metered dose inhaler consists of three major components:

Tin plated still is usually used for small volume aerosols

Drug may be dissolved in the propellant system

The actuator in the valve assembly prevents leakage of the formulation when the valve is in the closed position

If the drugs are suspended or emulsified in the propellant system, constant agitation during manufacture and using is required

The drug that may be dissolved in the propellant system should be insoluble

Smaller spray particle size can be achieved after complete propellant evaporation and it is or is supposed to be a simplified manufacturing process

If a drug is dissolved in the propellant system, the chemical degradation may occur faster

Drug may be suspended or emulsified (dispersed) in the propellant system

If the drugs are suspended or emulsified in the propellant system, higher doses may be delivered and physical instability might be a problem

If the drugs are suspended or emulsified in the propellant system, they cannot be used to deliver insoluble drugs.

Valve discharge rate of an aerosol is the amount of the drug discharged per unit volume

Quality assurance

Packaging, labeling and storage

Which of the following are auxiliary labels for packaging, labeling and storage?

Patients should be advised about importance of co-ordination between pMDI actuation and breathing

During patient counseling, the patients should:

The pharmacists are not allowed to put any label on aerosol container because only the manufacturer can do that

If multiple dosing is recommended in administering a pMDI, the patients need to wait for about 1 minute interval between actuations