胺在鼻腔注射后的药理动力学和大脑分布

Drug distribution within the body is a complex process influenced by several factors, including perfusion rate, the rate at which the bloodstream transports drugs to tissue. This limitation becomes particularly significant when dealing with highly lipophilic drugs. In such cases, the rate at which the drug can move across membranes is crucial, and if the membrane is highly permeable to the drug, distribution becomes rate-limited by perfusion.
Perfusion rate-limited distribution relies on the...

Intravenous anesthetics are drugs administered parenterally to induce anesthesia or sedation. Propofol is a widely used agent formulated as a 1% emulsion in soybean oil, glycerol, and egg phosphatide. It induces rapid anesthesia primarily due to its rapid distribution from the bloodstream to target tissues and is metabolized in the liver. However, it can cause significant pain on injection and hypertriglyceridemia. Fospropofol, a water-based prodrug of propofol, lacks these adverse effects.

The potency and duration of action of local anesthetics (LAs) are determined by their pharmacokinetics. Pharmacokinetics describes how LAs are absorbed, distributed, metabolized, and eliminated from the body. When administered to the vascular tissues, LAs are quickly absorbed and enter the systemic circulation, reducing their localized effects. Adding vasoconstrictors such as epinephrine to LAs reduces their absorption into the systemic circulation, making them clinically effective. The...

Choosing the appropriate route of drug administration is significantly influenced by two key factors: the therapeutic objectives and the inherent properties of the drug being used.
Administering drugs via inhalation allows for the direct delivery of gaseous, volatile substances or droplets to different parts of the respiratory tract. One of the advantages of the inhalation route is the rapid absorption of drugs into the circulatory system, which is possible because of the large surface area of...

The drug distribution process within the human body is a complex interplay of various physicochemical properties inherent to the drugs. These properties, including molecular size, ionization degree, partition coefficient, and stereochemical nature, significantly impact how drugs permeate biological membranes to reach their target tissues.
Small molecules with a molecular weight below 500 to 600 Daltons can easily pass through the capillary membrane, gaining access to different tissues. Larger...

All neuromuscular blocking agents are injected intravenously because they are poorly absorbed from the GI tract. Rapid onset is achieved with intravenous administration, although absorption is also adequate from an intramuscular injection. Since these agents are highly ionized, they do not readily penetrate cell membranes or cross the blood-brain barrier.
Instead, they are transported by the blood to different tissues. Muscles with a greater blood supply (arteries) and blood flow receive more...