Everything About PLGA Polymer Dissolution
- Barret
- Date: June 3,2023
The ability of PLGA to dissolve in the body has revolutionized the way medications are administered, especially for long-term treatments. PLGA-based products have been used to deliver a range of drugs, from vaccines to cancer therapeutics, and have shown promising results.
In this article, we will delve deeper into what PLGA dissolve is, how it works, and the benefits it offers in the medical field. We will also explore the challenges faced in developing PLGA-based products and new developments in the field.
How does plga polymer dissolve?
PLGA is a biodegradable polymer that can be dissolved by a wide range of solvents, depending on its composition. The dissolution of PLGA is mainly caused by the hydrolysis of its ester linkages in the presence of water. Different solvents can affect the dissolution rate and extent of PLGA by influencing the water uptake, swelling, and diffusion of the polymer.
There are three types of solvents that can dissolve PLGA: full solvents, non-solvents, and selective solvents.
- Full solvents are solvents that dissolve PLGA regardless of its L:G ratio. Examples of full solvents are acetone, chloroform, ethyl acetate, and dimethyl sulfoxide (DMSO). Full solvents are useful for preparing PLGA solutions for various applications, such as electrospinning, spray drying, or solvent evaporation. However, full solvents may also have some drawbacks, such as high toxicity, volatility, or cost.
- Non-solvents are solvents that do not dissolve PLGA at all. Examples of non-solvents are ethanol, hexane, water, and castor oil. Non-solvents are useful for precipitating PLGA from solution or for washing away residual solvents from PLGA products. However, non-solvents may also have some drawbacks, such as low compatibility with PLGA or poor removal of impurities.
- Selective solvents are solvents that dissolve PLGA depending on its L:G ratio. Examples of selective solvents are hexafluoroisopropanol (HFIP), toluene, and anisole. Selective solvents are useful for separating different PLGAs when used together in one product or for controlling the size and morphology of PLGA particles. However, selective solvents may also have some drawbacks, such as high toxicity, low availability, or complex separation processes.
The mechanism behind the selective solubility of PLGA in different solvents is not fully understood. However, some possible factors that influence the solvent-PLGA interactions are:
- The polarity of the solvent and the PLGA. Polar solvents tend to dissolve polar PLGAs better than non-polar ones. For example, HFIP is a highly polar solvent that can dissolve high glycolide PLGAs better than low glycolide ones.
- The molar volume of the solvent and the PLGA. Solvents with smaller molar volumes tend to diffuse into semi-crystalline glycolide-rich domains more effectively than larger ones. For example, anisole has a smaller molar volume than ethyl acetate and can dissolve high glycolide PLGAs better than low glycolide ones.
- The hydrogen bonding ability of the solvent and the PLGA. Solvents that can form hydrogen bonds with the carbonyl groups of PLGA tend to dissolve it better than those that cannot. For example, DMSO can form hydrogen bonds with PLGA and dissolve it better than hexane that cannot.
Factors that affect PLGA dissolution
PLGA dissolution is influenced by various factors, such as:
- The ratio of lactic acid (LA) to glycolic acid (GA) in PLGA. A higher LA:GA ratio results in a stiffer, stronger polymer with slower degradation rates. Conversely, a lower LA:GA ratio produces a softer polymer with faster degradation rates.
- The molecular weight of PLGA. A higher molecular weight results in a slower degradation rate and vice versa. Additionally, the molecular weight affects the mechanical properties such as tensile strength and elasticity of PLGA.
- The shape and size of PLGA material. The shape and size affect the surface area and water uptake of PLGA, which in turn affect the hydrolysis rate of PLGA. Smaller and more irregular shapes tend to have faster degradation rates than larger and more regular shapes.
- The temperature and pH level of the environment. A higher temperature and a lower pH level accelerate the hydrolysis rate of PLGA due to increased water activity and autocatalytic effect.
- The presence of enzymes or microorganisms. Some enzymes or microorganisms can catalyze the hydrolysis of PLGA, such as lipases, esterases, and fungi.
These factors should be considered when designing and optimizing PLGA-based drug delivery systems for different applications and scenarios.
Also Read: PLGA Polymer: Ultimate Buying Guide
Summary
In this blog post, we have learned that PLGA is a biodegradable polymer that can be dissolved by different solvents depending on many factors, such as the ratio of lactic acid to glycolic acid, the molecular weight, the shape and size, the temperature and pH level, and the presence of enzymes or microorganisms..
We hope that this blog post has given you a better understanding of PLGA dissolution and its implications for drug delivery systems. If you have any questions or comments, please feel free to contact us.
