"增强口服药物吸收:克服生理和药物障碍,改善生物可用性"

When a drug is taken orally, it undergoes a journey starting from the gastrointestinal (GI) tract, passing through the portal vein, reaching the liver, and finally entering the systemic circulation. This process involves the absorption of the drug across the GI tract. The liver is the primary site for metabolizing the drug, with some metabolism also occurring in the gut wall. This journey significantly reduces the quantity of the drug that reaches the systemic circulation, a phenomenon known as...

The pharmacokinetic journey of oral drugs begins with a crucial first pass through the hepatic portal system, called the first-pass effect. This first pass significantly impacts bioavailability — the proportion of a drug that enters systemic circulation and is available for therapeutic action. The primary route sees the drug absorbed by intestinal membranes and then shunted to the liver via the hepatic portal vein. Here, pre-systemic elimination occurs as drugs face metabolism or biliary...

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...

The physicochemical characteristics of drugs play a crucial role in formulating stable and bioavailable drug products. The solubility of a drug, governed by the varying pH along the GI tract and its dissociation constant (pKa), is pivotal in determining its ionization state and absorption rate. Notably, weak acids and bases remain unionized and are absorbed more rapidly.
Enhanced drug absorption can be achieved by reducing particle sizes and increasing surface areas, thereby facilitating...

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...

The process of drug absorption signifies the transition of a drug from its site of administration into the plasma. This process is influenced by various factors, including the route of administration, the anatomy of the absorption site, the mechanism of absorption, gut motility, and the drug's physicochemical properties.
When drugs are injected intravenously, they directly enter the systemic circulation. Alternatively, orally administered drugs navigate through the gastrointestinal (GI)...