Can we assume from FTIR that our drug is encapsulated in micelle or not or we must have to go for 2-D NMR?
in my opinion, Cryo-TEM may be the best way to determine the location of drug in polymeric micelle. In another way, you can try confocal microscope if your drug have fluorescence effect.
Electron microscopy is a good answer for you. Cryo-TEM or SEM, depending on the size of your micelle.
If you micelles are big enough(>5 microns) the best bet would be florescence imageing using confocal imaging in Z scan.
SEM will give you topographical data i.e only the image of surface. you will not know what is inside the polymer under any condition.
I you go with TEM you will have be very careful in choosing the staining chemical. You would want one which would attach with the drug not with the polymer.
hey actually my polymeric micelle is nm in size and the problem with my work is that as per literature with increase in pH, salt or temperature the solubility of drug in micelle must be increased but with one of my work this is not happening.
my polymeric micelle is PEO-PPO block copolymer in which along with increasing above mentioned the PEO gets dehydrated and core become larger and hence solubility increases but what I assume is that my drug is not that much hydrophobic and hence in might get located in palisade layer formed of PEO and hence upon dehydration the drug might be removed from micelle palisade payer
is my concept true?
or else how can I deal with the problem?
Nanometres you say, hmm. In that case, my only idea is HRTEM with EDS or ELLS, but, there is one catch, your drug must have some element differing it from the polymer. Then you can try to do EDS (EELS) elemental mapping. It is rather difficult on nm size samples and rather very difficult on polymer samples in nm size :(
On the other hand, you can use FTIR or Raman spectroscopy, if your drug have some characteristic bonds with one or the other polymer phase.
Hi Urjita!
In my opinion the microscopic method is not suitable for being sure of encapsulation because this method just shows the core-shell particles and not drug molecules. If your drug has fluorescence properties like Doxorubicin then you may use fluorescence microscopic technics otherwise it is hard to solve become sure of encapsulation.
In some cases if your drug has some molecular interaction with micelle core you may use calorimetric technics to find out encapsulation. One usual method is DSC (differential scanning calorimetry). For example is most cases crystalline molecules like PTX or Triamcinolone have molecular interaction with lipid core of PEG-PE micelle.
how can I find location of Rifampicin, isoniazid and pyrazinamide in pluronic micelle?
What is the importance of the location of these agents in micelle? We just need to become sure of encapsulation..
@ Ebrahim Saadat
actually the problem with my work is that as per literature with increase in pH, salt or temperature the solubility of drug in micelle must be increased but with one of my work this is not happening.
my polymeric micelle is PEO-PPO block copolymer in which along with increasing above mentioned the PEO gets dehydrated and core become larger and hence solubility increases but what I assume is that my drug is not that much hydrophobic and hence in might get located in palisade layer formed of PEO and hence upon dehydration the drug might be removed from micelle palisade payer
is my concept true?
or else how can I deal with the problem?
if i remember correctly, characterization of such fine emulsion is done by sensitive scattering techniques. The best would be small angle neutron scattering but that is not a feasible option pretty much anywhere. May be you choose a scattering technique which is compatible with you like SAXS or XAS.
The drug will be encapsulated either in the hydrophobic part or the hydrophilic part of the polymer micelles depends upon the nature of the drugs you have once. I would relay a bit more on literature and make an educated guess cos PEO-PPO is widely studies ampiphile
High-resolution NMR (in deuterated water) is the best option. By comparing the chemical shift in the absence and presence of the drug, you can see which surfactant signals are most affected by the presence of the drug. In addition, more sophisticated NMR techniques, such as NOE can be used to evaluate which drug specific groups are in the close neighbourhood of which surfactant chemical groups.
2D NOESY is helpful for resolving this issue. The cross peaks between drug and polymeric micelle will give a picture on location of drug molecule in the polymeric micelle. It is understood in many cases polymer mostly resides in the palisade layer rather entering into the core. This also can be exploited using 13C nmr chemical shifts of drug with and without polymer micelle.
You may use 13C nmr chemical shifts of drug with and without polymer micelle (In this approach avoid internal reference, use an external referencing method) The difference when plotted against carbon gives an idea on the preferential location of polymer with drug (This approaches already applied to surfactant micelle-drug systems). I have no idea on FTIR for this matter.
- Badges
- Science topic
- Similar topics
- Chemistry
- Pharmacology
- Pharmaceuticals
- Drugs