Absorption Kinetics
Absorption Kinetics - Related Videos
03:07
Kinetic Molecular Theory: Molecular Velocities, Temperature, and Kinetic Energy
0 Views •
2020
The kinetic molecular theory qualitatively explains the behaviors described by the various gas laws. The postulates of this theory may be applied in a more quantitative fashion to derive these individual laws. Collectively, the molecules in a sample of gas have average kinetic energy and average speed; but individually, they move at different speeds. Molecules frequently undergo elastic collisions in which the momentum is conserved. Since the colliding molecules are deflected off at different...
08:07
Enzyme Assays and Kinetics
0 Views •
2023
Enzyme kinetics describes the catalytic effects of enzymes, which are biomolecules that facilitate chemical reactions necessary for living organisms. Enzymes act on molecules, referred to as substrates, to form products. Enzyme kinetic parameters are determined via assays that directly or indirectly measure changes in substrate or product concentration over time. This video will cover the basic principles of enzyme kinetics (including rate equations) and kinetic models. The concepts governing...
01:19
Drug Absorption: Factors Affecting GI Absorption
0 Views •
2023
The process of oral drug absorption can be influenced by several factors. Weakly acidic drugs tend to be absorbed more readily from the stomach due to their nonionized state. However, absorption may be less efficient in the upper intestine, where drugs are often ionized. Interestingly, despite the stomach's apparent advantage for drug absorption, its mucous layer can hinder diffusion. Its surface area is also smaller than the intestine's, which can further slow down the absorption rate. In...
06:14
The Isolation of Flowing Mesenteric Lymph in Mice to Quantify In Vivo Kinetics of Dietary Lipid Absorption and Chylomicron Secretion
0 Views •
Cited by 1 •
2022
The present protocol describes a detailed surgical protocol for isolating flowing intestinal lymph in response to intraduodenal nutrient infusions in mice. This allows for the physiological determination of total intestinal lipid absorption and chylomicron synthesis and secretion in response to various experimental nutrients.
01:25
Carbohydrate Absorption
0 Views •
2025
Carbohydrates are essential macronutrients that serve as the body's primary energy source. Their digestion begins in the mouth, where salivary amylase partially breaks down complex carbohydrates such as starch into smaller oligosaccharides. This mechanical and enzymatic activity prepares carbohydrates for further processing in the gastrointestinal tract. After being swallowed, the partially digested carbohydrates mix with gastric secretions in the stomach. However, the acidic environment...
FAQs
Dissolution, membrane permeability, gastrointestinal conditions, formulation, and local blood flow jointly influence the speed of uptake. A drug must first become available from its dosage form, cross biological membranes, and encounter sufficient perfusion for entry into circulation. Changes in any of these steps can alter the concentration-time profile, shifting the timing and magnitude of clinical effects.
First-order input changes according to the amount of drug remaining at the absorption site, whereas zero-order input supplies drug at a relatively constant rate. These different input patterns produce distinct concentration-time profiles and can influence onset, peak behavior, and duration. Recognizing the pattern helps pharmacologists interpret how a formulation or administration process shapes exposure.
The absorption rate constant characterizes the rate of drug input, while bioavailability describes the fraction reaching systemic circulation. A drug may enter circulation rapidly but incompletely, or slowly with a greater overall fraction absorbed. Considering both measures prevents rate and extent from being treated as interchangeable and supports more meaningful comparisons among dosing conditions or formulations.
Researchers use concentration-time data and pharmacokinetic models to evaluate how formulations alter absorption rate, extent, and profile. Model-based comparisons can identify delayed or incomplete uptake and estimate parameters such as the absorption rate constant and bioavailability. These results help determine whether observed differences reflect the formulation, gastrointestinal conditions, or another factor affecting drug entry.
Altered gastrointestinal conditions, differences in formulation, limited dissolution, reduced membrane permeability, or changes in blood flow can delay or reduce uptake. The resulting exposure may show a later effect, lower systemic availability, or a changed concentration-time pattern. Identifying these possibilities helps clinicians interpret unexpected responses and consider whether altered absorption contributes to variable drug effects.
Absorption information helps connect a dosing regimen with the timing and magnitude of systemic exposure. Clinicians and pharmacologists can use absorption parameters and concentration-time profiles to compare regimens, anticipate altered exposure, and interpret therapeutic monitoring results. This is particularly relevant when delayed or incomplete uptake, formulation differences, or interactions may change the expected clinical response.