Drug delivery methods like oral inhalation, nasal sprays, transdermal patches, eye drops, intravitreal injection,  and rectal administration provide localized effects with reduced toxicity.
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs through the...

Drug distribution within the body is a dynamic process involving the movement of a drug in two directions across various compartments: from the bloodstream into tissues (tissue uptake) and from tissues back into the bloodstream (tissue release or redistribution). This process is passive and primarily driven by two variables: the concentration gradient between the bloodstream and the extravascular tissues and the drug's ability to cross the cell membrane.
Initially, the free drug in the...

Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...

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...

Since eddy currents occur only in conductors, magnets can separate metals from other materials. For example, in a recycling center, trash is dumped in batches down a ramp, beneath which lies a powerful magnet. Conductors in the trash are slowed by eddy currents, while nonmetals in the trash move on, separating from the metals. This works for all metals, not just ferromagnetic ones.
Other major applications of eddy currents appear in metal detectors and the braking systems of trains and roller...

The volume of distribution refers to the theoretical volume necessary to contain the entire amount of an administered drug at the same concentration observed in the blood plasma. The body's intracellular fluid compartment, which makes up two-thirds of the total body water, is contrasted with the extracellular fluid compartment—comprising plasma and interstitial fluid—that accounts for one-third. The volume of distribution can vary depending on the characteristics of the drug.