This week, I began another release study. As mentioned in my last post, the goal of this study was to see the differences in drug release between different masses of gels (related to the surface area to volume ratio as the gels are placed into a vial) and to double check my technique as my results from
my last test looked wonky.
Last Monday (the week during Spring Break), I actually went to lab and prepared for this release study, so that I could start it the following week. Because there are time points one day and two days after the start of the study, my mentor (who takes time points for me when I am not there), I prefer to start release studies on Mondays and so I need to prefer much beforehand.
So, this Monday, with preparation finished, I was able to start the release study quickly and take a couple of time points before I left. Later the night and Tuesday, my mentor took more time points. On Wednesday, I took another time point and ran a test to see amount of drug released so far from the gels.
Here is a graph of the cumulative release over these four days (Sorry for the poor quality, I had to take a screenshot since I don't have paint on this laptop and I cannot find how to copy and paste from Excel or attach files on Blogger):
If you cannot see it well, here is a summary: the top three lines are from the gels without the salt with the topmost line being the gel with the lowest mass. The bottom three lines are from the gels with the salt with the highest of the those three (the purple one) being the lowest mass as well.
Overall, I am mostly satisfied with this data/graph because the difference between the release profiles of the gels with and without the salt are as large as expected (my mentor performed a similar procedure previously without the various masses). Furthermore, that difference is mostly constant with the different masses in the gel. This is especially seen with the lowest mass curves as they are both significantly higher than the other two masses (I used 200 mg, 300 mg, and 400 mg).
However, one reason for doubt is the flatness of the curve after two days. As the curve becomes more flat, the more likely it is that the release is ending. In other words, the slope of the line between each time point is always decreasing. Thus, do the bottom three lines, or any really, reach 100% release? If not, I may have made a mistake somewhere. To check this, I plan to take a time point next Monday (7 days after the study has started and usually around the time when release ends) and see the release.
Nevertheless, the positives outweigh the negatives so far in this case, and so the following week, I want to start a new release study, going back to the first release study I did in which I tested various acids and salts and their effects on release. Hopefully, this time my results make more sense and say something more meaningful.
See you next week!
Russell Llave
Great work, Russell!
ReplyDeleteDoes a time point measure how much gel remains that has not yet been released? In a medical environment, does the release need to be a full 100% to be considered successful? Is there an acceptable "range" for the release to prove effective?
A time point measures how much drug has been released between the previous time point (or start of the release study) and that current time point.
DeleteThat's why in the procedure, once I take some solvent out and place it in a tube, the contents from which I add to a plate reader, I replace the solvent. Thus, the amount of drug recorded in the next time point is the amount of drug released between that time point and the previous time point.
More specifically, with the data, I used time points at 1 hour, 6 hours, 24 hours, and 48 hours. To find the total release of drug at 24 hours, I add the release measured in the 1 hour, 6 hour, and 24 hour.
In an engineering sense, the gel should eventually have a release of 100% because the gel will eventually breakdown completely. Thus, if I don't reach 100% I may have processed the data wrong or made a mistake in the procedure.
The more data you collect, the more confident you can be in your results.
ReplyDeleteAre you able to follow your mentor's experiments while you are in the lab conducting your own? Is your mentor working on something related?
My mentor is focusing more on other projects right now, and he occasionally explains them to me. I also help with those other projects if I have extra time. Nevertheless, basically all of the projects (including mine) focus on the use of one hydrogel, particularly its properties and its applications.
DeleteGreat job on your results! I really enjoy that you're including graphs each week--it's very helpful in understanding your results for the more chemistry-challenged.
ReplyDeleteAs for the results themselves, will the release always be greatest regardless of the amount of salt in the beginning hours? Is there any mechanism or process that allows for a regular release?