脂质体覆盖试验揭示了常见处方药物的意想不到的膜相互作用

Orally administered drugs primarily enter the systemic circulation via passive diffusion through the intestinal membranes. The drug's absorption is influenced by drug stability in the gastrointestinal GI tract, membrane permeability, the surface area available for absorption, luminal drug concentration, and residence time in the lumen. Drug permeability can be enhanced by adjusting the lipophilicity, polarity, or molecular size of the drug, promoting its passive transport across intestinal...

Drug absorption within the gastrointestinal (GI) tract is a complex process influenced by several critical factors, including the site pH, the drug's dissociation constant (pKa), and the drug's lipophilicity. The GI tract exhibits a pH gradient, with an acidic environment in the stomach and a more alkaline environment in the small intestine. This pH variation directly affects the ionization state of drugs.
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles...

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...

Passive transport is a method of drug absorption where small, lipid-soluble drugs can move across the cell membrane. This movement happens along the concentration gradient, which is a natural flow from higher to lower concentration areas. The speed at which the drug moves is directly related to its lipid–water partition coefficient. This means that the more a drug dissolves in lipids, the faster it diffuses or spreads throughout the body. It is important to note that most drugs are either...

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.

The pharmacokinetic journey of drugs from solid oral dosage forms into systemic circulation is multifaceted. It begins with disintegration, a prerequisite ensuring a solid dosage form's subdivision into minute particles. Dissolution occurs next as these granulated entities solubilize in gastrointestinal fluids. This solubilization is crucial for the succeeding stage, permeation, which describes the traversal of the drug across the intestinal membrane and its subsequent entry into the blood...