I hardly tried with w/o/w microparticles preparation method for gatifloxcin ocular delivery but it didn't work. So I have to test something else to reach the suitable size for ocular delivery with good entrapment efficiency EE%. But I need a proven protocol by these two methods because i don't have much time.
Thank you all
I have experience in both preparation techniques ?
but there are a few questions I want to ask u ?
1- what is ur target particle size ?
2- What is the solubility of ur compound ?
3- what type of polymer that ur using ? did u look to the Tg temperature ?
u should keep in ur mind that there is no magic formula that could be applied directly to get ur nano-particles ? it need a lot of time, if this is ur first expeience in this field.
Kind regards
A single tip ultrasonic homoginizer can be used for emulsification of either oil-in-water or water-in-oil emulsions.
dear D. ahmad
I am working on ocular drug delivery..so the particle size depending on USP should be less than 20 micrometer (none of them 25 micron)
my drug is Gatifloxacin its solubility is pH dependent with best solubility between 2-5 pH.
my polymer is Polycaprolacton with molecular weight 14000 g/mol
and The fact it is not my first experience but unfortunately I find difficulties to get good results in Gatifloxacin encapsulation with suitable size. despite I've experimenting many ways such as nanoprecipitation method and double emulsification method and It has taken a long time but unfortunately, I did not get the desired results.
thank you for your feedback
yes try to use a very strong emulsifier like PVA (polyvinyl alcohol) which reduce particle size very dramatically compared with tween another approach try to use probe sonication device If u have it or high speed small scale homogenizer it will reduce the particle size.
the quatity of the aqoues phase also play a role in determination of the particle size.
Naam, poly vinyl alcohol is an emulsifier, jeyjed, since it provides a more stable barrier between the phases, minimizing leackage from the inner phase to the continous one, due to its low diffusion, because of its hihger Mw, than smaller surfactants. Since PVA is wate soluble, it should be dissolved in the aqueous phase. For ocular use , it*s not good to use soniation probes, since they emit small metallic fragments that are harmful on the cornea. Better use a high speed homogenizer. A way to increase EE is to use a high viscosity in the inner phase, slowing down the diffusion, of its contents, hence decreasing the outleakage. To obtain a small particle size, while stirring the emulsion, you should increase the temperature and use vaccum or some low pressure, to solidify the dropletsby evaporating the organic solvent. Before the droplets aggregate and coalesce, of course, the substance to be entrapped should have a favorable partioning towards the inner phase , to keep it there, instead of migrating out from the droplets. For instance, if you're using a ionizable substance, to keep in an organic phase, it should be in its nonionic form. / Saba al sheir ! J o h a n at www.ontarget.chemistry.com , Uppsala, Al-Suwid.
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