Related Experiment Video
Updated: Aug 31, 2025

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Dissolution Behavior of Weakly Basic Pharmaceuticals from Amorphous Dispersions Stabilized by a
Derek S Frank1, Prateek Prasad1, Luca Iuzzolino2
1Particle Engineering Lab, Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States.
Amorphous solid dispersions (ASDs) using Eudragit EPO show promise for weakly basic drugs, but their performance depends on gastric pH. Careful formulation is needed to manage drug release and prevent precipitation.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
Background:
- Amorphous solid dispersions (ASDs) enhance dissolution of hydrophobic drugs.
- Weakly basic drugs present challenges due to pH-dependent solubility and precipitation issues in ASDs.
Purpose of the Study:
- To investigate the release mechanisms of amorphous dispersions containing weakly basic drugs (posaconazole, lumefantrine) from a basic polymer (Eudragit EPO).
- To compare dissolution behavior with ASDs stabilized by acidic/neutral polymers.
- To understand the benefits and drawbacks of basic polymeric stabilizers for weak bases.
Main Methods:
- Preparation and dissolution testing of amorphous solid dispersions (ASDs).
- Utilized model weakly basic pharmaceuticals: posaconazole and lumefantrine.
- Employed a basic polymer, Eudragit EPO, and compared with acidic/neutral polymers.
Main Results:
- Eudragit EPO ASDs achieved supersaturation in gastric conditions, sustained at neutral pH.
- Dissolution was sensitive to initial gastric pH, causing precipitation or crystallization for lumefantrine and posaconazole, respectively.
- The polymer's impact on gastric pH and drug solubility influenced release.
Conclusions:
- Eudragit EPO offers benefits for ASDs with weak bases, enabling sustained supersaturation.
- Sensitivity to initial gastric pH is a key liability, requiring careful formulation design.
- Understanding these benefits and liabilities guides the development of robust ASD formulations for weak bases.
More Related Videos
11:42Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers
Published on: June 20, 2019
11:32Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants
Published on: December 23, 2013
Related Concept Videos
Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Factors Influencing Drug Absorption: Pharmaceutical Parameters
Factors Affecting Dissolution: Particle Size and Effective Surface Area
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Factors Affecting Dissolution: Drug pKa, Lipophilicity and GI pH
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles...
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model