I am working with silica nanoparticles and now thinking of synthesizing biodegradable nanoparticles using polymers. But I am worried about the stability of the nanoparticles. Does anyone have any suggestion and solutions for this?
And also which will be the suitable and effective method to go for the synthesis of biodegradable nanoparticles.
Thank you...........(;
Dear Asha, The method for preparation depends on which type of polymer you will use. Myself, I used PLG, using the double emulsion solvent evaporation method (to incorporate hydrophilic substances). If you incorporate substances that are hydrophobic, you will only have to make a single o/w emulsion. Usually microparticles are prepared this way, but I've also made nanoparticles with that method. If I remember correctly, I used higher energy for the second emulsification of the w/o/w emulsion and lower concentration of PLG in the organic solvent. If the polymeric emulsifier is not enough, to prevent aggregation of the prepared nanoparticles, I suggest to add some other steric stablizer, e g Tween 80.
Dear Johan .
Thank you.
Johan i have a query .....
Will this method be suitable for the reselase of the incorporated drug at the targeted site..........
There are several methods available in the literature. You can tune the properties like size, drug loading and degradation rate based on your application . The degradation rate of some synthetic polymers are months to years based on the type and cross-linking between them. Go thro' the attached reviews...
Dear Asha, now you're really into research, discussing ways to control the drug release from biodegradable polymers. In my experience, using PLG, there are several tricks to use. The observed release will be a combination of the degradation of the polymer and its permeability. The degradation of PLG is manly determined by its molecular weight and the fractions of lactictide- and glycolide monomers. The degradation is slower, using high molecular weight of the PLG and using PLG where one of the monomers dominate over the other. Of course, the more mixed the polymer is, the less crystalline and permeable it becomes. Low Mw-PLG can release the drug in a week. High Mw PL can release the drug in a year. If one uses PLG with too slow drug release, one can try to dissolve some additive in the polymer solution, which disturbs the polymer structure. That will also increase the drug release.PLG is not a cross-linked polymer.
To achieve high drug loadings, the phase in which the drug is dissolved should have a high viscosity, preventing the drug to escape during emulsification. It's of course, an advantage if the drug is strongly partitioned in its phase , compared to the other phase.
Talking about the targeted site, one need to administrate the nanoparticles in a proper way. To answer your question one must know what site you're aiming to. An alternative, to nanoparticles, is to use the PLG in the form of an implant, if it can be located near the site of action, by a non-invasive procedure. Implants are much easier to prepare and to produce in large scale.
Some people have the opinion that the lactic acid, formed during the degaradation gives a low local pH, destructive to incorporated protein drugs. We have incorporated antibodies and enzymes, in vitro and in vivo, that retained their bioactivities. there are (and has been) also commercial PLG-products, that contain peptides and growth hormone, with retained bioactivities.
Thank you Johan,
Quite interesting....
Johan could you please forward me the link of the paper of your work.......if its ok with you.
thanks once again.
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