Yield/Loading efficiency equations - assistance needed

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jackiemorris01
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Yield/Loading efficiency equations - assistance needed

please help, I am getting myself confused over clarifiaction of a number of equations; your assistence would be much appreciated, Jackie

i can't see it here but I have enclosed an attachment with this request. please would someone let me know if you can't access it.
J

protoldo
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Hola. Your attachment is not

Hola. Your attachment is not visible. Try send it again.Bye

jackiemorris01
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thank you for letting me know

thank you for letting me know - I shall try again now. please let me know if you can/can't see it
jackie

jackiemorris01
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2nd try J

2nd try
J

jackiemorris01
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Attachement

Attachement

protoldo
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Hola, Now your attachment is

Hola, Now your attachment is open. I am biologist, but I understand that microspheres are composed of a polimer and the active drug. If the adecuate proportion of drug is 20% that means 10mg /50 mg of polimer. Probably for any compoud the capacity of polymer would be greater than 10mg/50mg in this case 15.82, so if you are able to immobilize 14.91 you have a yield of 94%.Please, if you consider wrong this reasoning forgive it. Have a nice day

jackiemorris01
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Thank you protoldo,

Thank you protoldo,
we agree that the Incorporation (encapsulation yield is 94% - i.e. 94% of the drug has been caught up in the polymer during manufacture.
However I have made a silly error in the attachment - the 15.82 theoretical weight is 20% of 79.1 mg of microspheres used.... (I am so used to using 50mg I put that in error).
using the correct figures of 14.9 
                                                   79.1 x100

the result is 18.84 - (not 29.8 as I put in my attachment)
my query - (which I may have worded badly) is that some literature refers to this equation/figure as either the drug loading or recovery yield.
am I correct in thinking that this figure supports my initial supposition that I had approx 20% ratio between drug/polymer - i.e. 10mg/50mg.
as these two equations seemed to be quoted together in most of the articles, should I be able to determine a corrolation/link?
I appreciate your assistance, thank you,
J

Bettye
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 Are you trying to figure out

 Are you trying to figure out how much of your drug has been bound or encapsulated into or onto a polymer?

jackiemorris01
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Hi Bettye,

Hi Bettye,
I  put weighed drug in ethanol (79.11mg) agitated, centrifuged rinsed and driedresulting in dry weight 14.91mg. Useing the previous equation the result was 94% loading.... which I presume means I have encapsulated 94% of my expected drug in the polyer. I am happy with that.
this is shown as Encapsualtion Efficincy in some literature although I understand the more suitable term is Yield Efficiancy.

However, when I then looked at the literature (e.g.Maghsoodi AAPS 10.1.3.2009) the equation for yield i.e. weight recovered divided by Weight total x100 is also labelled as drug loading. using this equation my results are 18.84%.
Based on the drug /polymer ratios I have used I was expecting 20% w/vol increase.
my confusion is the interchanging of the terms..........is my 18.8% a loading or a yield - to my mind a yield is the drug released from the microspheres.
I know this is pedantic but I am anxious to try and use the correct terminology as well as the correct equations!
any clarification would ber VERY much appreciated.
J

Bettye
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 I think encapsulation

 I think encapsulation efficiency is the term you are looking for.
When I think of yield, I think of % of a substance produced or recovered from starting material. 
In this case, it seems that you want to know how much drug is associated with the polymer.

You might also look at:
http://dx.doi.org/10.1021/ac048439n
http://tinyurl.com/2c3fv34

I hope this helps. It's not within my area of expertise, but I did ask an analytical chemist.

jackiemorris01
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Thank you Bettye for your

Thank you Bettye for your reply, both links look good but especially the second as it looks a little more relevent at this stage of my research.
regards,
Jackie