Chapter 3
Pharmacokinetics: Drug Absorption
Fasi di Somministrazione e Terapia dei Farmaci: Panoramica
Drugs are chemicals used for diagnosing, treating, or preventing diseases. The four phases of drug product preparation are pharmaceutic, pharmacokinetic, ...
Assorbimento del Farmaco: Panoramica
The process of drug absorption involves the passage of a drug from its administration site into the plasma. It is influenced by factors like ...
Somministrazione di Farmaci: Panoramica
The choice of a drug's delivery route depends on its physicochemical features, such as lipid or water solubility and ionization, as well as ...
Somministrazione del Farmaco: Via Enterale
Enteral administration of drugs can occur via oral, sublingual, and buccal routes. Oral administration involves swallowing a pill; in sublingual delivery, ...
Somministrazione del Farmaco: Via Parenterale
The parenteral route delivers drugs directly into the systemic circulation. It facilitates rapid onset of action and is the preferred route for poorly ...
Somministrazione di Farmaci: Percorsi Vari
Drug delivery methods, such as oral inhalation, nasal sprays, transdermal patches, eye drops, intravitreal, and intrathecal injections, mostly offer ...
Membrane Cellulari e Trasporto dei Farmaci
Drugs encounter multiple barriers to reach their target site within the body, including the multiple-cell layered skin, single-layered intestinal ...
Meccanismi di Assorbimento dei Farmaci: Trasporto Paracellulare, Transcellulare e Vescicolare
After administration, drugs must cross cell membranes to reach their target site in the body. For example, oral drugs must navigate intestinal epithelial ...
Diffusione Passiva: Panoramica e Cinetica
Passive diffusion allows small lipophilic drugs to cross the cell membranes along a concentration gradient. During this process, the drug absorption rate ...
Trasporto Attraverso Pori e Trasporto di Coppie Ioniche
Most drugs cross the membrane barriers through passive transport mechanisms, moving along the concentration gradient.
Many low molecular weight drugs move ...
Trasporto Mediato da Carrier
Carrier-mediated transport facilitates the movement of lipid-insoluble drugs via membrane-spanning transporters.
As drug concentration increases during ...
Diffusione Facilitata
The plasma membrane consists of several transporters or carrier proteins interspersed between the lipid bilayer that facilitate solute transport.
...
Trasporto Attivo
Active transport is the process of moving lipid-insoluble molecules against their concentration gradient using energy and specialized transporters.
There ...
Trasporto Vescicolare: Endocitosi, Transcitosi ed Esocitosi
Endocytosis is a process where the cell membrane folds inward as vesicles to engulf large-sized drugs.
This process includes pinocytosis and
...
Fattori che Influenzano l'Assorbimento del Farmaco: Parametri Anatomici
Drug absorption entails transporting drugs from the administration site to the bloodstream.
GI motility moves drugs through the digestive tract, entering ...
Fattori che Influenzano l’Assorbimento del Farmaco: Stato Patologico e Farmacologia
Various disease conditions can influence the body's blood flow and the functioning of the gastrointestinal system, influencing the drug absorption ...
Fattori che Influenzano l'Assorbimento del Farmaco: Parametri Fisico-chimici
The physicochemical properties of drugs are essential parameters for designing stable and bioavailable drug products.
A drug's solubility depends on ...
Fattori che Influenzano l'Assorbimento del Farmaco: Parametri Farmaceutici
For drug products like tablets and capsules, dissolution and absorption are greatly influenced by the manufacturing methods and inactive components or ...
Fattori che Influenzano l'Assorbimento del Farmaco: Dissoluzione del Farmaco
The drug absorption process from solid oral dosage forms, like tablets or capsules, into the systemic circulation involves sequential events.
Firstly, ...
Fattori che Influenzano l'Assorbimento del Farmaco: Eliminazione Presistemica
Most oral drugs are absorbed from the intestines into the hepatic portal vein, passing through the liver before entering the systemic circulation. This ...
Teorie della Dissoluzione: Modello dello Strato di Diffusione
Dissolution, the process of drug particles dissolving in a solvent, is explained by the diffusion layer model.
According to this model, initially, a thin ...
Teorie della Dissoluzione: il Modello di Danckwerts e il Modello della Barriera Interfacciale
Various dissolution theories elucidate factors impacting the dissolution rate.
Danckwert's model postulates that the dissolution medium shows ...
Fattori che Influenzano la Dissoluzione: Dimensione delle Particelle e Area Superficiale Effettiva
Recall the Noyes-Whitney equation, which suggests a direct correlation between dissolution rate and a drug's surface area.
A solid drug's surface ...
Fattori che Influenzano la Dissoluzione: Polimorfismo, Amorfismo e Pseudopolimorfismo
Drug dissolution is influenced by polymorphism, which refers to the existence of a drug substance in multiple crystalline forms like polymorphs, solvates, ...
Fattori che Influenzano la Dissoluzione: pKa del Farmaco, Lipofilia e pH GI
Drug absorption in the gastrointestinal tract depends mainly on the absorption site's pH, the drug's dissociation constant, and lipophilicity.
The ...
Fattori che Influenzano la Dissoluzione: Permeabilità del Farmaco, Stabilità e Stereochimica
Most orally administered drugs travel through the GI tract and diffuse passively through intestinal membranes to enter the systemic circulation.
The ...
Metodi per Studiare l'Assorbimento dei Farmaci: In Vitro
Various in vitro methods utilize different biological barriers to study drug absorption.
In the diffusion cell technique, a donor compartment with the ...
Metodi per Studiare l'Assorbimento dei Farmaci: In Situ
In situ drug absorption methods mimic in vivo conditions by perfusing a drug solution through an anesthetized rat's intestinal segment.
It includes ...
Vie di Assorbimento dei Farmaci Non Orali ExtravascolarI
Non-oral extravascular routes mainly diffuse drugs passively to reach the systemic circulation. Factors influencing extravascular drug absorption include ...
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