Related Experiment Video
Updated: Jun 20, 2026
10:33
Delivery of Therapeutic siRNA to the CNS Using Cationic and Anionic Liposomes
Published on: July 23, 2016
10.5K
Preparing Size-Controlled Liposomes Modified with Polysaccharide Derivatives for pH-Responsive Drug Delivery
Shin Yanagihara1, Yukiya Kitayama1,2, Eiji Yuba1,2
1Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Osaka, Japan.
Life (Basel, Switzerland)
|November 25, 2023
Summary
Liposome size impacts drug release. Smaller liposomes show enhanced pH-responsive release, but high cholesterol content reduces responsiveness, crucial for drug delivery applications.
Area of Science:
- Biotechnology
- Materials Science
- Pharmaceutical Sciences
Background:
- Liposome particle size is critical for controlling drug release due to variations in bilayer curvature and lipid packing.
- Previous studies utilized liposomes of 100-200 nm, leaving the effect of size on pH-responsive properties unclear.
Purpose of the Study:
- To investigate the impact of liposome size on pH-responsive content release.
- To explore the role of cholesterol in liposome stability and responsiveness.
Main Methods:
- Liposome size was controlled using extrusion through polycarbonate membranes of varying pore sizes.
- Cholesterol was incorporated into liposomal lipid components to assess its effect on size stability.
- pH-responsive content release was measured at neutral and weakly acidic pH conditions.
Main Results:
- Liposome size directly correlated with polycarbonate membrane pore size.
- Smaller liposomes demonstrated significantly higher pH-responsive content release compared to larger ones.
- Liposomes containing 50 mol% cholesterol exhibited suppressed content release, even under acidic conditions.
Conclusions:
- Liposome size and cholesterol content are key factors for developing stable liposomes at physiological pH.
- Precise control over liposome size and cholesterol levels is essential for optimizing pH-responsive drug delivery systems.
More Related Videos
Related Concept Videos
01:19Modified-Release Drug Delivery Systems: Rate-Programmed II
Rate-programmed drug delivery systems release drugs in a controlled manner to maintain therapeutic levels. Three main designs include reservoir, matrix, and hybrid systems.Reservoir systems consist of a drug core enclosed within a membrane that controls drug release. In non-swelling reservoir systems, polymers like ethyl cellulose or polymethacrylates are used. These do not hydrate in aqueous media and control release through membrane thickness, porosity, or insolubility. This type includes...
01:20Modified-Release Drug Delivery Systems: Influencing Factors
Modified-release drug delivery systems are designed to optimize the therapeutic effect of drugs by minimizing side effects, reducing the dosage required, and controlling drug release to align with pharmacokinetic and pharmacodynamic needs. The system depends on two key factors: the drug's release from the formulation and its movement through the body to the target site. Unlike conventional dosage forms, where absorption is the limiting step, the rate of drug release is the key determinant in...
01:23Modified-Release Drug Delivery Systems: Classification
Modified-release drug delivery systems improve drug efficacy and minimize side effects by controlling the rate and location of drug release. These systems fall into three categories: rate-programmed, stimuli-activated, and site-targeted.Rate-programmed systems release drugs at a predetermined rate, maintaining consistent therapeutic levels and reducing fluctuations that could lead to toxicity or subtherapeutic effects. These systems use polymeric matrices, reservoir-based designs, or osmotic...
01:22Modified-Release Drug Delivery Systems: Rate-Programmed I
Rate-programmed drug delivery systems (DDS) are designed to release drugs at specific, controlled rates to maintain consistent therapeutic levels. These systems are categorized based on their release mechanisms, including dissolution-controlled DDS, diffusion-controlled DDS, and combined dissolution-diffusion-controlled DDS.In dissolution-controlled DDS, the release rate depends on the slow dissolution of the drug itself or the surrounding matrix. Drugs with inherently slow dissolution rates,...
01:30Modified-Release Drug Delivery Systems: Stimuli-Activated
Stimuli-activated drug delivery systems are designed to release drugs in response to specific physical, chemical, or biological stimuli. These systems often utilize hydrogels—three-dimensional, hydrophilic polymer networks capable of swelling in aqueous environments and retaining significant fluid volumes. Upon exposure to particular stimuli, these hydrogels undergo structural transitions that allow the embedded drug to be released. Due to this adaptive behavior, such systems are also called...
01:24Site-Targeted Drug Delivery Systems: Polymeric Carriers
Polymeric carriers enhance targeted drug delivery by increasing efficacy while minimizing off-target effects. These carriers comprise a biodegradable polymeric backbone integrated with functional elements that enable targeting, improve physicochemical properties, and regulate drug release.Targeting MechanismsThe targeting ability of polymeric carriers is mediated by a homing device, which is a molecular recognition component designed to selectively bind to specific tissues or cells. Monoclonal...