1. Inhalation administration
Pathway: absorbed by lung epithelial cells or respiratory mucosa → into blood circulation.
Features:
It takes effect quickly, which is equivalent to intravenous injection. The lungs have a large surface area.
Can avoid the first round of elimination.
It is especially suitable for lung diseases.
Disadvantages → The drug dosage is difficult to control, which will stimulate lung epithelium.
Application: gas, volatile drugs (such as inhaled anesthetics), atomization of drug solutions, fine gas or solid particles dispersed in the air.
For example:
Isoproterenol aerosol can be used to treat bronchial asthma.
A spray with dense fog particles is used for local treatment of nasopharynx, such as antibacterial, anti-inflammatory, expectorant and nasal congestion.
In addition, lung absorption is also an important way to absorb drugs and environmental pollutants.
2. Nasal administration
Pathway: drugs → abundant villi and capillaries of nasal mucosa → enter the blood circulation. Medicine → nasal mucus and cilia → from turbinate to nasopharynx → clearance.
Features:
Avoid the first round of elimination.
Drugs with molecular weight less than 1000 are absorbed quickly; Macromolecular drugs can also be collected and sorted through absorption and medical education network to achieve effective bioavailability.
Application:
Patients with migraine accompanied by nausea and vomiting, or patients who are not suitable for oral preparations, can use the medical education network to collect and sort out sumatriptan and zolmitriptan nasal sprays.
Treatment of osteoporosis with calcitonin nasal spray.
Diabetes insipidus, desmopressin nasal administration.
Abuse drugs or drugs, such as cocaine, are inhaled through the nasal cavity.
3. Local administration
Play a role in the local area.
Topical skin administration: anti-infection, such as clotrimazole cream collected by Medical Education Network, is directly applied to the skin to treat fungal infections.
Topical ocular administration:
Atropine is dripped into eyes, which is used to dilate pupils and refractive patients.
Features:
It can avoid first-pass elimination, is insensitive to immune response, and is suitable for the administration of polypeptide drugs. Intravascular drug therapy.
Drugs are irritating, which can lead to tears and damage eye tissues.
The drug is easy to lose and the retention time is short.
Drugs that stay for a long time, such as eye ointment, are collected and sorted by some medical education networks, which will affect vision.
4. Transdermal administration
When the excipient is applied to the skin, the drug dissolves out and can enter the epidermis.
The speed and degree of absorption depends on:
(1) medication area.
(2) Fat solubility of drugs.
(3) Physical characteristics of the skin at the site of administration, complete skin absorption, poor collection and sorting; For chafed, burned or reddened skin, drugs can be absorbed quickly.
Application:
Sustained-release pharmaceutical preparations usually use transdermal patches, such as nitroglycerin, an anti-angina drug, and fentanyl, an analgesic drug.
Insecticides with high fat solubility can be absorbed through the skin and collected by medical education network, causing poisoning.