Pharmacokinetics: Drug Absorption

Drugs are chemicals used for diagnosing, treating, or preventing diseases. The four phases of drug product preparation are pharmaceutic, pharmacokinetic, …

The process of drug absorption involves the passage of a drug from its administration site into the plasma. It is influenced by factors like …

The choice of a drug's delivery route depends on its physicochemical features, such as lipid or water solubility and ionization, as well as …

Enteral administration of drugs can occur via oral, sublingual, and buccal routes. Oral administration involves swallowing a pill; in sublingual delivery, …

The parenteral route delivers drugs directly into the systemic circulation. It facilitates rapid onset of action and is the preferred route for poorly …

Drug delivery methods, such as oral inhalation, nasal sprays, transdermal patches, eye drops, intravitreal, and intrathecal injections, mostly offer …

Drugs encounter multiple barriers to reach their target site within the body, including the multiple-cell layered skin, single-layered intestinal …

After administration, drugs must cross cell membranes to reach their target site in the body. For example, oral drugs must navigate intestinal epithelial …

Passive diffusion allows small lipophilic drugs to cross the cell membranes along a concentration gradient. During this process, the drug absorption rate …

Most drugs cross the membrane barriers through passive transport mechanisms, moving along the concentration gradient. Many low molecular weight drugs move …

Carrier-mediated transport facilitates the movement of lipid-insoluble drugs via membrane-spanning transporters. As drug concentration increases during …

The plasma membrane consists of several transporters or carrier proteins interspersed between the lipid bilayer that facilitate solute transport. …

Active transport is the process of moving lipid-insoluble molecules against their concentration gradient using energy and specialized transporters. There …

Endocytosis is a process where the cell membrane folds inward as vesicles to engulf large-sized drugs. This process includes pinocytosis and …

Drug absorption entails transporting drugs from the administration site to the bloodstream. GI motility moves drugs through the digestive tract, entering …

Various disease conditions can influence the body's blood flow and the functioning of the gastrointestinal system, influencing the drug absorption …

The physicochemical properties of drugs are essential parameters for designing stable and bioavailable drug products. A drug's solubility depends on …

For drug products like tablets and capsules, dissolution and absorption are greatly influenced by the manufacturing methods and inactive components or …

The drug absorption process from solid oral dosage forms, like tablets or capsules, into the systemic circulation involves sequential events. Firstly, …

Most oral drugs are absorbed from the intestines into the hepatic portal vein, passing through the liver before entering the systemic circulation. This …

Dissolution, the process of drug particles dissolving in a solvent, is explained by the diffusion layer model. According to this model, initially, a thin …

Various dissolution theories elucidate factors impacting the dissolution rate. Danckwert's model postulates that the dissolution medium shows …

Recall the Noyes-Whitney equation, which suggests a direct correlation between dissolution rate and a drug's surface area. A solid drug's surface …

Drug dissolution is influenced by polymorphism, which refers to the existence of a drug substance in multiple crystalline forms like polymorphs, solvates, …

Drug absorption in the gastrointestinal tract depends mainly on the absorption site's pH, the drug's dissociation constant, and lipophilicity. The …

Most orally administered drugs travel through the GI tract and diffuse passively through intestinal membranes to enter the systemic circulation. The …

Various in vitro methods utilize different biological barriers to study drug absorption. In the diffusion cell technique, a donor compartment with the …

In situ drug absorption methods mimic in vivo conditions by perfusing a drug solution through an anesthetized rat's intestinal segment. It includes …

Non-oral extravascular routes mainly diffuse drugs passively to reach the systemic circulation. Factors influencing extravascular drug absorption include …