Hey all
what are the ways by which an encapsulated drug inside BSA may escape from its encapsulation.
We had synthesised curcumin encapsulated BSA by desolvation method followed by centrifugation at 12k rpm for 30 minutes and water-bath sonication for 5 minutes.
We had sent the sample for FE-SEM analysis and could find curcumin in the background .
Is this the curcumin that got leaked after encapsulation or is it that one which wasn't removed even after multiple washing steps and centrifugation?
How do to find this out?
Does sonication break encapsulation?
If so how to prevent the leakage of encapsulated curcumin?
An image of the same has been attached for your kind reference.
Thanks and best
Hi V H Krishna Prasad ,
Although it can minimize aggregation and improve the dispersion of the particles, sonication can definitely impact encapsulation and fragilize nanoparticle structure. If it is included in your protocol, its duration and intensity will need to be optimized in such way that you end up with decently dispersed, stable drug-loaded particles.
Ideally, wash steps would eliminate free curcumin. However, in practice, it is likely that you will still have some level of the free curcumin in the background of your particles due to leakage. As well, curcumin loosely bound to the surface of BSA can detach overtime and contribute to a background of free curcumin.
In addition to desolvation, crosslinking can help minimize the escape of the drug associated with BSA and improve the stability of your particles. Crosslinking can further generate aggregates which can skew particle size readings, and potentially impact particle uptake and their overall efficacy. However, this can be dealt with by selecting a fitting crosslinking agent and an optimal duration for the crosslinking reaction.
There are several crosslinking agents out there. Glutaraldehyde is a widely used one for albumin. EDC is another one to consider. In the preparation steps, one recommendation would be to add the crosslinking agents before the centrifugation steps and sonication.
Check out these manuscripts and their methods, especially regarding crosslinking and sonication.
Article The effect of different desolvating agents on BSA nanopartic...
Article Albumin and functionalized albumin nanoparticles: Production...
There a few ways to assess levels of the bound vs free curcumin at each steps of your methodology to identify which step impact most its retention in the BSA articles. Fluorescence-based methods are a good ones since parameters such as anisotropy, lifetime -and perhaps absorbance or fluorescence spectra- can change depending on the interaction of curcumin with its environment.
Article Nanotechnology-Applied Curcumin for Different Diseases Therapy
This is just a general comment for your question, but perhaps more details on your current methodology for the preparation of the BSA-curcumin particles will generate a more precise answer.
Hope this helps though :)!
Dear Akpedje Serena Dossou , Thank you for your suggestions and the links as well. While preparing we do sonicate but only after the addition of 8% glutaraldehyde prior to sonication. I have referred the cited papers, however I couldn't figure out much from them, one paper had used sonication for 10 seconds. Is there anything else that can be done to prevent drug escape?
Hi V H Krishna Prasad ,
Thanks for the additional clarification on the crosslink in your methodology :)
If you are wanting to improve %EE and stability of drug retention, optimizing the crosslinking reaction could help... Here are some manuscripts pertaining to your study with some modifications on the crosslinking step.
Article 1, check page 8311.
Article Curcumin-loaded galactosylated BSA nanoparticles as targeted...
Article 2, page 120
Article Preparation and Characterization of Albumin Nanoparticles En...
Article 3, page 226 (refers back to article 2)
https://briefs.techconnect.org/wp-content/volumes/Nanotech2013v3/pdf/464.pdf
For the sonication step, article 2 performs this in a bath sonicator over 5 mins. Perhaps, switch to a bath sonicator in case you are sonicating with a probe.
This review below has some discussion of different factors and additional ingredients that can be added to improve stability of BSA-based nanoparticles. Page 36 has a suggestion for a cross-linking agent.
Article Factors Affecting the Synthesis of Bovine Serum Albumin Nano...
Of note, you may need to balance prevention of drug escape with the expected action/dynamics of your BSA-curcumin particles. Complete prevention of drug escape may not be achievable in practice, especially when the particles are introduced in a biological system, where degradation happens with time. The impact of this "unwanted" drug release depends on what the expectations are for these BSA-curcumin particles.
If controlled release of curcumin in plasma is an end-goal for these BSA-curcumin particles, then, you don't want to completely prevent drug escape. In contrast, if you are expecting the BSA-curcumin particles to have full retention of the curcumin before target cells uptake the curcumin, then, you want to avoid drug escape as best as you can.
You probably already planned or performed this, but in case not, I would recommend a release behavior and a stability study. These would give you a bit more insight into the integrity of your particles with time. You can then utilize your particles in their stability window so they can produce optimal results.
Hi again V H Krishna Prasad ,
Just noticed from your initial post that you use water-bath sonication, so please disregard my last comment on the sonication by probe. As well, your methodology looks very similar to the ones in articles I added as references, so they may not be as helpful in addressing your particular issue.
Will let you know if I come across relevant methods that can help :)
Thank you Akpedje Serena Dossou for your comments. Kindly let me incase you addition information regarding the same.
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