Hello guys, i would like to ask about my DSC thermogram results. There is an unexpected crowded peak that appeared on my thermogram result (the one in the blue circle). I have tried to search about the cause of it but I haven't found the answer to it yet. The sample that I made is a solid dispersion consisting pure drug of valsartan, PEG 6000, and Kollidon VA64, that are prepared using solvent evaporation method. Could someone please enlighten me about this? Thank you so much in advance.
The melting point of valsartan is 110 degree centegrate, it's not shown in the chart, also the melting point of PEG 6000, and Kollidon VA64 is 62 and 140 C respectively, so I think either there is impurities in the pure drug or change in the physical properties due to environmental effect resulted in these peaks
Hi, repeat the measurement to see if the peak oscillation is systematic or random. If it is systematic, it might be some impurities as suggested by @Mahmood Haiss . O. The other hand, random variation of the signal is usually due to physical instability of the sample - e.g. when the evaporating fumes move with the sample or sometimes even deform the pan.
There are many reasons for your case. First, I do agree with Petr to repeat at least three times and compare the obtained thrmograms to make a conclusion. I do suggest you run individual components, say valsartan, PEG 6000, and Kollidon VA64, and then compare the thermogram of your formulation. It is common to see fewer curves than the original ones or even some shift of the curves because of the blending and possible reactions among constituents during heating. All the best.
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Powders