Dear Kavita, are you saying that you prepared some nanoparticulate system (by using a particular - not disclosed - process, by adding known amounts of arsenic plus PLGA, plus other ingredients(??)).

You don't know how much As is "floating around" in the supernatant and how much is adsorbed, entrapped (etc) in the particles, Is that right?

You can, for sure, calculate the concentration/dilution of your initial preparation that inhibits/kills/etc 50% of the cells but what does that tells you regarding the impact of the PLGA particles, the PLGA-As loaded and or As alone in the IC?

Am I missing something?

HTH, Luis

Thanku for replying. sir, i have prepared arsenic loaded plga nanoparticles by W/O/W double emulsion evaporation technique ( briefly i took 200mg plga +4 ml methylene chloride then added 2% arsenic trioxide and 2.25% pva ..mixed it sonicate it. Centrifuge collected powder dried it..characterize it. Now i have to check its effect against breast cancer cell. For that i m performing MTT assay, i dissolve 10mg nanopartcle powder in 1 ml dmso n make serial dilution 50 ug/25ug/12.5/6.25... but i dint get any effect.

Now my question is do i need to calculate drug loading capacity first ..than according to that should make my stock drug.because i dont know in 1mg powder how much arsenic would be there...

Dear Kavita, First of all, please try to write in English without using "u" meaning "you", "n" as for "and", etc. You are free to use your own writing style in SMS's, whatsapp's etc messages sent to your friends but, despite some informality here, IMHO we all should avoid those spelling "shorts".

Regarding your question, you state you "didn't get any effect". What do you mean? a) no reduction of viable cells or b) reduction to zero - in all of them?

In case (if the "no change" is due to a not suitable concentration range) a) you need to increase the concentration of the first nano-dispersion, in case of b) you should dilute it!

Did you performed the As assay in your nanoparticle powder? If not, you should do it but in such a way that you are only quantifying the As that is entrapped/encapsulated/adsorbed onto the particles. There are some additional issues that need to be addressed and experimentally performed in order to conclude what is causing the observed effect (the carrier, the As, both, etc).

HTH, Luis

I apologise for using informal words on such academic platform but as we are so much used to it , unconciously i am writting in such manner. I will take care of it as much possible.

Sir if you dont mind would you suggest me any good book dealing with such concepts of drug designing related to nanoparticles ? So that I can understand the basics..