Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism

Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism

Polymorphism refers to the existence of a drug substance in multiple crystalline forms, known as polymorphs. Recently, this term has been expanded to include solvates (forms containing a solvent), amorphous forms (non-crystalline forms), and desolvated solvates (forms from which the solvent has been removed).
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...

Polymer Classification: Crystallinity

Polymer Classification: Crystallinity

Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...

Pharmaceutical Alternatives: Polymorphic Form-Related and Particle Size-Related Therapeutic Nonequivalence

Pharmaceutical Alternatives: Polymorphic Form-Related and Particle Size-Related Therapeutic Nonequivalence

Changes in polymorphic forms can significantly influence the bioavailability of poorly soluble drugs. Although the FDA defines pharmaceutical equivalence based on having the same active ingredient, dosage form, and route of administration, it does not automatically disqualify products with different polymorphic forms. This means two products with different polymorphs can still be deemed pharmaceutically equivalent. However, polymorphic differences can affect properties like wettability,...

Passive Diffusion: Overview and Kinetics

Passive Diffusion: Overview and Kinetics

Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...

Mechanisms of Drug Absorption: Paracellular, Transcellular, and Vesicular Transport

Mechanisms of Drug Absorption: Paracellular, Transcellular, and Vesicular Transport

Drugs need to permeate cell membranes to reach their target sites after administration. Orally administered drugs must transcend intestinal epithelial membrane barriers to infiltrate the systemic circulation. Drugs with a molecular weight of less than 500 Daltons diffuse through gaps between neighboring cells, called paracellular pathways.
However, most drugs use the transcellular route, traversing directly through the cell membranes via two mechanisms: passive and active transport. Passive...

Drug Absorption Mechanism: Passive Membrane Transport

Drug Absorption Mechanism: Passive Membrane Transport

Passive transport is a method of drug absorption where small, lipid-soluble drugs can move across the cell membrane. This movement happens along the concentration gradient, which is a natural flow from higher to lower concentration areas. The speed at which the drug moves is directly related to its lipid–water partition coefficient. This means that the more a drug dissolves in lipids, the faster it diffuses or spreads throughout the body. It is important to note that most drugs are either weak...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Restoring warped document images through 3D shape modeling.

IEEE transactions on pattern analysis and machine intelligence·2006

Same author

Lamivudine prophylaxis reduces the incidence and severity of hepatitis in hepatitis B virus carriers who receive chemotherapy for lymphoma.

Cancer·2006

Same author

Influence of an amide group in methyl octadecanoates on the monolayer stability.

Langmuir : the ACS journal of surfaces and colloids·2006

Same author

The co-existence of two growth hormone receptors in teleost fish and their differential signal transduction, tissue distribution and hormonal regulation of expression in seabream.

Journal of molecular endocrinology·2006

Same author

Proteomic profiling of regionalized proteins in rat epididymis indicates consistency between specialized distribution and protein functions.

Journal of proteome research·2006

Same author

Identification of a new Neisseria meningitidis serogroup C clone from Anhui province, China.

Lancet (London, England)·2006

Search research articles

Related Experiment Video

Updated: Jul 15, 2026

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

A different diffusion mechanism for drug molecules in amorphous polymers.

Zhi-Jian Zhao¹, Qi Wang, Li Zhang

¹Department of Chemistry, Zhejiang University, Hangzhou 310027, People's Republic of China.

The Journal of Physical Chemistry. B

|April 13, 2007

Summary

Drug diffusion in polymers like PLA-PEG is crucial for controlled release. Molecular dynamics simulations show polymer chain wriggling, not free volume, primarily dictates aspirin diffusion, proposing a new drug transport mechanism.

More Related Videos

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Published on: August 15, 2016

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Published on: September 8, 2016

Related Experiment Videos

Last Updated: Jul 15, 2026

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Published on: August 15, 2016

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Published on: September 8, 2016

Area of Science:

Materials Science
Polymer Chemistry
Computational Chemistry

Background:

Polymer materials are essential for controlled drug delivery systems.
Understanding drug molecule diffusion within polymer matrices is critical for optimizing drug release profiles.

Purpose of the Study:

To investigate the diffusion behavior of aspirin, a model drug, in poly(lactic acid-co-ethylene glycol) (PLA-PEG) copolymers.
To elucidate the key factors governing drug diffusion in polymer matrices, specifically polymer chain wriggling and free volume.

Main Methods:

Utilized molecular dynamics simulations to model and analyze the diffusion of aspirin within varying ratios of PLA-PEG.
Examined the interplay between polymer chain dynamics (wriggling) and matrix free volume in influencing drug transport.

Main Results:

Polymer chain wriggling was identified as the dominant factor controlling aspirin diffusion in PLA-PEG.
Free volume plays a secondary role, becoming significant only when polymer chain wriggling is comparable between different polymer compositions.
A distinct diffusion mechanism for drug molecules, differing from small gas molecules, was proposed, highlighting diffusion coupled with polymer matrix movement.

Conclusions:

The diffusion of drug molecules like aspirin in polymer matrices is primarily governed by the dynamic motion of the polymer chains.
This study proposes a new model where drug molecules effectively 'hitchhike' on the wriggling polymer chains for transport.
Findings provide valuable insights for designing advanced polymer-based drug delivery systems with tailored release kinetics.