Aerosol: a preparation in which the drug is sprayed into a mist by mechanical (nebulizer or atomizer) action.
Inhalation: refers to the main drug itself with the characteristics of volatilization and sublimation for patients to inhale the preparation.
I. Aerosol features: fast-acting positioning, clean and sterile, stable, no local irritation, high cost.
Two, aerosol classification: inhalation aerosol, skin and mucous membranes, and space disinfection aerosol according to medical use.
By type of composition:
1, two-phase aerosol: solution type
2, three-phase aerosol: suspension or emulsion system type.
3, inhalation aerosol characteristics: mainly absorbed through the lungs Factors affecting the distribution of drugs in the respiratory system: gravity deposition, inertial embeddedness, Brownian motion Source: the examination of the big
1, the air flow of breathing: the amount of particles deposited with the amount of respiration is proportional to the amount of respiration, and the respiratory frequency is inversely proportional.
2, the size of particles: pharmacopoeia regulations below 10um, mostly less than 5um usually 0.5-5um is the most appropriate
3, the nature of the drug: passive diffusion, lipid / water partition coefficient is easy to absorb.
Composition of aerosols
I. Ejection agent: mostly liquefied gas, boiling point below room temperature at atmospheric pressure. Classification: chlorofluorocarbons, hydrocarbons, compressed gases chlorofluorocarbons: Freon, insoluble in water, solvent for fat-soluble drugs, stable in water, f11, f12, f114 Source: Examination
II, drugs and additives Source: Examination
Three, pressure-resistant containers
Four, the valve system
Preparation of aerosols
I. Aerosol prescription types and examples:
1, solution-type aerosol: isoprenaline hydrochloride aerosol : add ethanol as a potential solvent,
2, mixing and dissolving into a homogeneous phase,
3, vc as an antioxidant .
4, suspension aerosol: add surfactant as wetting agent, dispersant and suspending agent.
5, emulsion-type aerosol: the use of mixed ejection agent. Add emulsifier
Two, the preparation process of aerosol: pay attention to avoid microbial contamination.
Ejection agent filling:
1, pressure irrigation method: multi-purpose, simple equipment, small loss, no need for low temperature, but the pressure change is large. Source: the examination
2, cold irrigation method: the liquid cold to -20 ℃, the ejectant cold to 5 ℃ below the boiling point, fast, stable pressure, low temperature, water-containing varieties should not.
The quality of aerosol evaluation Source: Examination
1, safety, air leakage check
2, the amount of spray and spray times check
3, spray speed check Source: Examination
4, the fog particle size determination : three-phase inspection of the particle size
5, the amount of drug deposition of the effective site (in vitro) and efficacy (in vivo) evaluation
Spray, inhalation aerosol spray: refers to the application of compressed gas, oxygen, inert gases and other gases as the driving force of the sprayer or nebulizer spraying liquid droplets or semi-solid preparations, also known as pneumatic agents. The power to eject the liquid is compressed in the container of gas, but not liquefied. Source: exams
Nitrogen: small solubility, stable;
Carbon oxide: high solubility, change the ph of the liquid. inhalation powder aerosol: a preparation in which micronized drugs and carriers are in the form of capsules, blisters, or multiple dosage reservoirs in the form of a specially designed dry-powder inhalation device, where the patient is actively inhaling the aerosolized medication. Pay attention to moisture.