I am currently working in research entitled:
Development and Quality Control of a Sustained Release Ophthalmic Pharmaceutical Product Using Micro / In Situ Gelling for Gatifloxacin drug... and unfortunately went a whole year of time without access to the required results ...
The way that I wanted to prepare microparticle is the Double-emulsification method,and I have enlisted many of the research techniques, which revolve around the same theme,but unfortunately I did not get satisfactory results. I do not know what the problem is so I need your advice in the way of working ...
The problem is that the dimensions of the particles prepared from a class of 600 microns and entrapment efficiency about 70%, but of course it is not suitable for ophthalmic application ... and when trying to change the criteria to get the required dimensions 1-10 micron, the entrapment efficiency virtually non-existent less than 5%.....
I am currently running out of time so I really need urgently help
In W/O/W micropaticle production method, size and entrapment efficiency are dependent to different parameters such as rate of emulsification, rate of oil phase evaporation or diffusion,type of emulsifier and etc. I have some question: what is the properties of carrier used in this experiment? what method used for decreasing size of particles?
In order to give you some help we need to know the exact structure of the polymer you employed and the experimental parameters up to now evaluated.
As said before, you have to be more specific about what class of polymer you are using, the formulation conditions and so on.
Also, ask yourself if you can achieve the expected results by using another method (direct emulsification).
i am using polycaprolacton PCL as a polymer 1.5g in 15ml of Dichloromethane DCM, then i drop wise the drug solution 50mg/2ml Hcl 0.1N (with or without PVA 0.1% with molecular weight 89000) and emulsify the mixture by ultraturax with 15000 rpm for 5 min, after that i add this w/o emulsion into 50 ml of distilled water with 5% of tween 20, and it is homogenized again with ultraturax 6000 rpm for 2 min so w/o/w should be formed...I let the organic phase to evaporate by mechanical stirring 1000 rpm for 1 hour... but unfortunately like i said before the results are not as expected.. although i changed a lot of parameters (speed,time,polymer conc.,surfactants...etc.)
thank you all
I think it's better to add emulsifier (PVA) to second solution and decrease the stirring time in final stage. But O/W ratio is high (15 ml DCM per 50 ml water), decreasing this ratio may be resulted to better emulsification in final stage and increases in DCM evaporation rate which prevent of particle size growth.
I've experimenting with a lot of experiments, and till don't know yet what the problem is in the low encapsulation, for example, I tried out:
Different sizes of the three phases 2/7/50 2/7/200 2/15/50
Different speeds for the initial emulsification with different times 20000, 15000 and 11000 rpm
Different ratios of Tween 20 1.5%,3% and 5%
Different concentrations of polymer used 500mg, 1g, 1.5g and 2g
Different times of final stage of solvent evaporation 3hrs, 1h and 30min
so drs. I do really appreciate your suggestions but do you think that this method is not suitable for gatifloxacin drug??
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