Related Experiment Video
Updated: Jun 10, 2025
11:27
A Package of Established Analytical Tools to Investigate the Solid-State Alteration of Lipid-Based Excipients
Published on: August 9, 2022
2.0K
Dissolution of copovidone-based amorphous solid dispersions: Influence of atomic layer coating, hydration kinetics,
Emily G Benson1, Dana E Moseson1, Shradha Bhalla1
1Department of Industrial and Molecular Pharmaceutics, College of Pharmacy, Purdue University, West Lafayette, IN 47907, United States.
Journal of Pharmaceutical Sciences
|October 10, 2024
Summary
Atomic layer coating (ALC) improves amorphous solid dispersion (ASD) powder characteristics. However, ALC
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Drug Delivery
Background:
- Amorphous solid dispersions (ASDs) enhance drug solubility and bioavailability.
- Atomic layer coating (ALC) is a solvent-free technique for nanolayer ceramic coating of particles.
- ALC can improve powder properties and prevent drug crystallization in ASDs.
Purpose of the Study:
- To evaluate the effect of aluminum oxide coating thickness and conformality on ritonavir/copovidone ASD release.
- To investigate the influence of ALC on ASD hydration and phase separation.
- To assess the role of formulation in mitigating coating effects on drug release.
Main Methods:
- Coating of ritonavir/copovidone ASD particles with aluminum oxide via ALC.
- Preparation and dissolution testing of uncoated and coated ASD powders, neat tablets, and formulated tablets.
- Confocal fluorescence microscopy (CFM) to visualize particle hydration and phase separation.
Main Results:
- ALC had minimal impact on powder dissolution when defects allowed solvent penetration.
- In tablets, ALC slowed hydration, leading to drug-polymer phase separation and reduced release.
- Formulation with superdisintegrants and lactose restored rapid drug release from coated ASDs.
Conclusions:
- Hydration rate is critical for ASD performance in solid dosage forms.
- CFM is a valuable tool for understanding ASD release and phase behavior.
- Effective formulation strategies can overcome release limitations imposed by ALC.
Related Concept Videos
01:21Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
289
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...
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
289
01:28Factors Influencing Drug Absorption: Pharmaceutical Parameters
121
Solid dosage forms such as tablets and capsules undergo rigorous manufacturing processes to ensure stability and effectiveness. Their dissolution and absorption properties are influenced significantly by the choice of excipients (inactive ingredients that serve various roles in the formulation), and the methodology applied during production. The manufacturing parameters, such as compression force and granulation techniques, significantly affect dissolution rates. Elevated compression forces...
121
01:23Factors Affecting Dissolution: Particle Size and Effective Surface Area
750
Dissolution kinetics, an essential aspect of oral drug delivery, is significantly influenced by the drug's particle size. According to the Noyes-Whitney dissolution model, the dissolution rate correlates directly with the drug's surface area. The larger the surface area, the higher the drug's solubility in water, leading to a faster drug dissolution rate. Reducing particle size increases the effective surface area, enhancing the dissolution process. Micronization and nanosizing are...
750
01:15Theories of Dissolution: Diffusion Layer Model
698
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
698
01:20Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
179
Orally administered drugs primarily enter the systemic circulation via passive diffusion through the intestinal membranes. The drug's absorption is influenced by drug stability in the gastrointestinal GI tract, membrane permeability, the surface area available for absorption, luminal drug concentration, and residence time in the lumen. Drug permeability can be enhanced by adjusting the lipophilicity, polarity, or molecular size of the drug, promoting its passive transport across intestinal...
179
01:27Factors Influencing Drug Absorption: Drug Dissolution
424
The pharmacokinetic journey of drugs from solid oral dosage forms into systemic circulation is multifaceted. It begins with disintegration, a prerequisite ensuring a solid dosage form's subdivision into minute particles. Dissolution occurs next as these granulated entities solubilize in gastrointestinal fluids. This solubilization is crucial for the succeeding stage, permeation, which describes the traversal of the drug across the intestinal membrane and its subsequent entry into the blood...
424