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# Assay Calculation

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Gamalmostafa
Egypt

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Status: Frog Egg
 Topic Started by Gamalmostafa on 12/12/2006 17:56 PM

I have a problem in assay calculation. where I analyse hard gelatin capsule of Amoxicillin. the capsule contains 266 mg of Amoxicillin Trihydrate equivlaent to 250mg of amoxicillin. I use the following equation.
mg/cap = A t x W s( mg) x Dfu x P x Av. Fill Wt. of cap.
A s x Dfs x W t (mg) x 100
where
A t : the response of test solution.
A s : the response of standard solution.
Dfu : the dilution factor of test solution.
Dfs : the dilution factor of standard solution.
W t & W s : the weigh of Test and standard respectively.
P : is the purity of amoxicillin standard.( here is the problem)
where I have two assay of Amoxicillin working standard one is AS SUCH ( 85.9%) and ON DRY BASIS 98.8%) my question here when I use ON DRY BASIS potency should I have the result of mg/cap as amoxicillin base or WHAT???
Provided that the USP does not recommend drying the standard of Amoxicillin trihydrate).

Gamal Mostafa

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Status: Frog Egg
 Posted By Srinivasareddy.Attunuri on 1/1/2009 22:02 PM

If u are taking warking standard as is basis result is ammoxacilin base

If u are taking warking standard on dried basis result is ammoxacilin

Ajesh
India

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 Posted By Ajesh on 9/9/2010 10:42 AM

Nice Question.

As we have to find the content of amoxicillin trihydrate equivalent to Amoxicillin in mg per capsule of av.net.weight we have to use as such ie 85.9% for standard purity in calculation because rest of the percentage ,ie 14% may be of water molecule(as the R.S amoxicillin in its trihydrate form)

Last edited Sep 09, 2010, 22:28 PM by Ajesh

bUJJI
India

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 Posted By bUJJI on 9/14/2010 0:51 AM

Potency is always As such unless and otherwise specified. Potency on dried basis should not be considered. since You are getting the area of amoxicillin but not for LOD/WATER by HPLC. you have the absorbance for 85.9% potency.

Last edited Sep 14, 2010, 2:51 AM by bUJJI

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 Posted By Rajeshwari patel on 9/15/2010 1:51 AM

Nice quation.

If you are going to report your potency report on basis of Iu/mg you take  85.9% and if you want to report in IU/cap you take according to that be cause youar measuring replative potency which is coimng according to your standrd which you take for the estimation.

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 Posted By Durga Nautiyal on 11/18/2011 19:46 PM

If in Pharmacopia is not specifying wether value is calculated on As Such Basis OR On Anhydrous Basis then, which calculation we will used (As Such Basis OR On Anhydrous Basis).

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 Posted By Rajeshwari patel on 11/20/2011 17:50 PM

hi,

in this case you assy range unit is what ?  Iu? mg?please explain

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 Posted By Durga Nautiyal on 11/20/2011 18:01 PM

Hello Raj ji,

Actually this regarding the test chloride content i.e in IP limit is mentioned 5.0-5.5%w/w, but they are not specifying wether the specs is on As Such Basis OR On Anhydrous Basis.

Durga

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 Posted By aswini nalamalapu on 2/28/2014 3:24 AM

I HAVE A PROBLEM IN POTENCY CALCULATION, difference between assay on dried basis, assay on as is basis and assay on anhydrous basis? when we can calculate ssay on dried basis, assay on as is basis and assay on anhydrous basis?

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 Posted By aswini nalamalapu on 2/28/2014 3:24 AM

I HAVE A PROBLEM IN POTENCY CALCULATION, difference between assay on dried basis, assay on as is basis and assay on anhydrous basis? when we can calculate ssay on dried basis, assay on as is basis and assay on anhydrous basis?

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Status: Frog Egg
 Posted By amirali2820 on 10/25/2014 6:06 AM

i want to calculation p[otency for erythromycin ethyl succinate

pls help me to have calculation method and formula and sampl of calculateion

thanks alot

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