Investigating the properties of degradable starch microspheres

Abstract

Introduction: Improvements of the analytical methods used to study starch microspheres that may aid the development and analysis of medical device products.
Background: Some of the current methods used to study the starch microspheres may be time consuming, prone to errors (in cases of manual methods), in need of better reproducibility and robustness, and there is a demand to improve them.
Aim: The aim of these experiments was to develop and improve analytical methods that are used to study the properties of the microspheres and the materials that are used to create the spheres.
Methods: The visual and optical methods used to analyze the swelling of the spheres were investigated. A study of the sample preparation of the emulsifier Starch Acetate Butyrate (SAB), a key raw material when producing the spheres, was performed, and then analyzed using gas chromatography. Additionally, an automatic sampling method to be applied when investigating the degradation of the microspheres was developed using an ion chromatograph autosampler.
Results: A connection between the diameter of the fully swollen spheres and the time it takes for the sphere to reach this size was found. This may reduce the time of some analytical methods and ease the development of future sphere products. It was also found that spheres that swelled statically swelled similarly to the spheres that swelled dynamically. A sample preparation method to study the emulsifier was developed which resulted in higher reproducibility. The automatic sampling method to be applied during degradation studies was improved through quicker sampling with more efficient mixing.
Conclusion: Optical analysis of the microspheres gave useful information regarding the spheres size and swelling time. The SAB sample preparation method showed good reproducibility, but further investigations are needed to gain trustworthy accuracy of the measurements. Further development is needed for the automatic sampling method and for the analytical degradation method.

Popular Abstract

Degradable Starch Microspheres (DSMs), made from potato starch, can be formulated in various ways and used as medical devices to treat cancer and traumatic wounds, amongst other things. Improving methods for determining chemical and physical properties of these spheres might improve their development and analysis. The aim of this study is to improve the analytical methods used to study these properties as well as gain a deeper understanding about the technology.
The first properties investigated during this study was swelling and size of the spheres. This was analyzed using laser light that hits the sample and scatters, the intensity of the scattered light can then be modulated as a function of the time which allows for the determination of the radius of the spheres. The spheres absorb water and swell, increasing in volume until the sphere is fully swollen. The swelling can be measured as the size of the spheres increases with time. It was found that there is a connection between the size of the fully swollen sphere and the time it takes for the sphere to reach this size. The results may be used to optimize of analysis time for some of the analytical methods and increase the efficiency of development of future medical devices.
Another property that was investigated was the degradation of the spheres. The spheres are broken down to smaller sugar polymers, maltose, and glucose by the protein α-amylase in the body. This process is replicated in the lab using the protein in vitro and then the degradation is analyzed. The current analytical method uses a manual sampling method that is prone to human errors and is time consuming. Development of an automatic sampling method was started which showed promise, illustrating a path for further optimization.
There are batches of a key chemical used during the creation of the spheres that perform better than others and more information regarding this is needed for a better understanding of the chemical. The method to investigate the components of the chemical needs improvement. This was done by testing different factors that affect the preparation of the chemical to find factors that produced repeatable results. After the preparation the components of the chemical was separated and analyzed using a technique called gas chromatography. This analysis showed that repeatable results could be obtained but the accuracy of the analysis is faulty.

• author: Gustafsson, Vendela
• supervisor: Viveca Oltner
• organization: Department of Chemistry
• course: KEMR30 20231
• year: 2023
• type: H2 - Master's Degree (Two Years)
• subject: Chemistry
• keywords: Analytical Chemistry, Degradation, DLS, GC, Microsphere, Swelling
• language: English
• id: 9129619
• date added to LUP: 2023-06-28 11:35:01
• date last changed: 2023-06-28 11:35:01