作为活性成分的载体的:一项审查

Carrier-mediated transport is a pivotal process in drug absorption, particularly for lipid-insoluble drugs, and encompasses facilitated diffusion and active transport. Facilitated diffusion allows drugs to move along their concentration gradient without energy expenditure, while active transport utilizes ATP to drive drug movement against this gradient.
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...

Certain large, lipid-insoluble drug molecules that resemble amino acids, peptides, or glucose, require specialized carrier proteins to facilitate their diffusion across cell membranes. This transport can occur through either facilitated diffusion, which does not require energy input, or active transport, which does require energy input.
Facilitated diffusion is a passive process that utilizes human Solute Carrier (SLC) transporters. These transporters bind to the drug, undergo structural...

Prodrugs are a class of pharmaceutical compounds that undergo a biotransformation process within the body to be converted into a pharmacologically active drug. Prodrugs are designed to improve the therapeutic properties of the parent drug, such as enhancing bioavailability, increasing stability, or reducing toxicity. The concept of prodrugs revolves around modifying the chemical structure of the original drug to make it more effective or convenient for administration.
Prodrugs help overcome...

Drugs must traverse multiple biological barriers, such as multi-layered skin, single-layered intestinal epithelium, and the plasma membrane, to reach their target sites within the body. The plasma membrane, a highly structured composite of phospholipids, carbohydrates, and proteins, is the cell's protective boundary, facilitating selective substance exchange.
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.

Drugs need to permeate cell membranes to reach their target sites after administration. Orally administered drugs must transcend intestinal epithelial membrane barriers to infiltrate the systemic circulation. Drugs with a molecular weight of less than 500 Daltons diffuse through gaps between neighboring cells, called paracellular pathways.
However, most drugs use the transcellular route, traversing directly through the cell membranes via two mechanisms: passive and active transport. Passive...

Pore transport and ion-pair formation are critical mechanisms for the absorption and distribution of drugs in the body.
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited  but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...