Dear colleagues and academics,
For the research work we're conducting, we have synthesized active ingredient-loaded polymeric micelles. After finding the best formulation and preparing a big batch, we need to perform an antioxidant activity assay on these loaded micelles to make sure that this loading system preserves the active ingredient's antioxidant activity. For this, I have read many studies to look for a method. The problem is that all these articles do not specify some details. The 2 points that I'm currently wondering about are as follows:
- The analysis is to be performed on different concentrations of free active ingredient, as well as encapsulated active ingredient. The concentration for both should be the same for comparison (e.g., 1, 0.75, 0.5, ... mg/mL for both free and encapsulated active ingredient). In the case of the encapsulated active ingredient, is the concentration including the polymeric micelles' mass or just the concentration of encapsulated active ingredient?
- Do we need to dissolve (or disassemble) our loaded micelles before the DPPH analysis, or should we just leave it for hours with DPPH solution in the dark to analyze the antioxidant activity of the active ingredient it releases through time?
Thank you for your valuable time. Have a good day.
Kindly check https://link.springer.com/article/10.1007/s00204-011-0774-2
1. You should consider the corresponding concentration of the active ingredient, not the micelles.
2. The DPPH assay is usually performed in ethanol or methanol (DPPH is not soluble in water), and these usually disrupt nanoparticles. Here in the lab, we have actually used the DPPH assay to measure radical scavenging activity of nanoparticles containing vegetal extracts and found that simply mixing the suspension with DPPH is able to disrupt them and release the active ingredient.
The experiment of release over time would be another approach, but this kind of experiment is usually conducted in physiological conditions (aqueous PBS), and not ethanol or methanol.
You should take care with possible light scattering effects of insoluble material from the capsules, because they can interfere in the absorbance readings. To overcome this, we usually conduct the assays in tubes, centrifuge them, and then transfer to microtiter plates for reading.
Thank you Mr. Chinaza Godswill Awuchi and Mr. Daniel Carneiro Moreira for you valuable answers. The articles provided by Mr. Chinaza were very vital to enrich my knowledge about the mechanisms of antioxidants and the various assays available to measure their free radical scavenging activity. On the other hand, Mr. Daniel's answers have perfectly pinpointed the points that I needed to understand.
- Badges
- Science topic
- Similar topics
- Chemistry
- Pharmacology
- Medical Pharmacology
- Clinical Pharmacology