The Pharmacokinetics of Drugs Delivered to the Upper Nasal Space

AbstractPharmacokinetics (PK) includes how a drug is absorbed, distributed, metabolized and eliminated. The compartment providing this information is usually  the plasma. This is as close to the tissue of interest that we can get, although biopsies may be obtained to give “tissue levels” of drugs. Ultimately, the goal of PK is to understand how long the drug is actually engaged with the target in the tissue of interest after a dose has been administ ered. Most drugs at some point in their development will have been administered intravenously (IV), which acts as the standard for 100% bioavailability. By comparing various routes of administration to IV, the percentage of drug delivered to the plasma, on a dose-normalized basis, can be calculated and is referred to as the “absolute bioavailability”. As pharmacology has advanced and more drugs have become available, many older products have been reformulated to be given by routes other than those originally intended (often oral). As the drawbacks of oral (or IV) administration have become better appreciated, non-oral, non-IV formulations and methods of administration have become more popular. Nasal administration is one route that has historically been overlooked as an alternative to oral administration—particularly for products needing rapid and non-invasive access to the target tissue—mostly via the blood stream. But attention is now focused on nasal administration for direct access to the brain, as that has the po...
Source: Pharmaceutical Medicine - Category: Drugs & Pharmacology Source Type: research