克服小分子药物生物可用性的挑战:对关键因素和方法的审查

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...

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...

Bioavailability refers to the extent and rate at which a drug reaches systemic circulation in its active form. Extent refers to the amount of the drug that makes it into circulation, while rate is the speed at which it enters circulation. It is influenced by several factors critical for optimizing drug formulations, dosing regimens, and therapeutic outcomes.Physicochemical properties of drugs and formulationsThe solubility, stability, and dissolution rate of a drug significantly impact its...

Bioavailability is a critical pharmacological concept that measures the extent and rate at which an active drug ingredient or therapeutic moiety enters the systemic circulation, remaining unchanged. It's a pivotal factor in determining a drug's efficacy and safety.The Biopharmaceutics Classification System (BCS) plays an essential role in drug development by categorizing drugs into four classes based on their solubility and permeability. This classification aids in understanding drug absorption...

Bioavailability is a critical factor in determining a drug's effectiveness. It refers to the proportion of a drug that enters the circulation when introduced into the body and is, as a result, able to have an active effect. Enhancing bioavailability is essential for drugs with poor solubility, as it can significantly impact their therapeutic efficacy. Various methods are employed to increase the solubility of drugs, thereby enhancing their bioavailability.Micronization and nanonization are...

After oral administration, poor permeability often limits the rate at which drugs are absorbed through the intestinal epithelium. Enhancing drug permeability is crucial for effective therapy, and several strategies have been developed to overcome this challenge.One effective strategy involves the use of lipid-based formulations. These formulations enhance dissolution and solubility, targeting physiological mechanisms to increase drug absorption. This includes stimulating bile salt secretion,...