Related Experiment Video
Updated: May 30, 2026

Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
[Correlation between absorption rates of beta-adrenoreceptor antagonists in rat small intestine and their molecular
1Department of Pharmacy, Zhejiang University City College, Hangzhou 310015, China.
Objective:
To study the correlation between the absorption rate constants of beta-adrenoreceptor antagonists in rat small intestinal segments and their molecular structural parameters.
Methods:
The net atomic charges and the molecular volumes of 11 beta-adrenoreceptor antagonists were obtained with the semiempirical self-consistent field molecular orbital calculation CNDO/2 method and Mont Carlo method respectively, using the minimum energy conformation obtained from the optimization of the standard molecular geometry with the molecular mechanics MM+ method. The stepwise multiple regression analysis was used to obtain the correlation equations.
Results:
The absorption rate constants of beta-adrenoreceptor antagonists in rat jejunum or ileum were well linearly correlated with the sum of the net charges of all hydrogen atoms and the molecular volumes. The beta-adrenoreceptor antagonist with higher lipophilicity, weaker hydrogen-bonding potential,and smaller molecular volume had greater absorption rate constants.
Conclusion:
The absorption rate constants of beta-adrenoreceptor antagonists in rat small intestinal segments are mainly related with their lipophilicity,hydrogen-bonding potential and molecular size.
Related Concept Videos
Drug Absorption: Factors Affecting GI Absorption
In...
Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Factors Influencing Drug Absorption: Anatomical Parameters
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Methods for Studying Drug Absorption: In vitro
The diffusion cell method uses a two-compartment cell, including a donor compartment with the drug solution, which simulates the environment where the drug is applied, and a receptor compartment with a buffer solution, which simulates the environment...
Methods for Studying Drug Absorption: In situ
The Doluisio method involves perfusing a prepared segment of a rat's small intestine with a solution of radiolabeled drug and a non-absorbable marker. This helps to differentiate between absorbed and non-absorbed drug concentrations. The intestinal segment is connected at both ends using tubing and syringes,...

