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Correction Factors of related substances

Posted: Sun Aug 26, 2012 11:50 am
by Amalia
Hello everyone,
i am new in this forum so please excuse me if i make no sense!
to get straigth to the point, we have a dilemma as far as the calculation of correction factor of the related substances of Ranitidine HCl is concerned. Our final product is expressed as % Ranitidine (as base) but our working std is Ranitidine HCl. When calculating the % of the related substance we take into consideration the convertion of Ranitidine HCl to Ranitidine (base) but our problem is ...do we have to make this convertion when we calculate the correction factor of each related substance? I tried to make my point clear, i hope i did. If there is anyone that can help me please answer!

Thank you in advance

Re: Correction Factors of related substances

Posted: Mon Aug 27, 2012 12:11 am
by DR
Calculate your standard concentration in terms of the base, then all is in terms of that including RS.

Re: Correction Factors of related substances

Posted: Mon Aug 27, 2012 5:30 pm
by Amalia
Thank you for your reply,
so, if i understood what you said, you mean to calculate my standard in terms of base in order to use it to the formula i use to calculate the correction factor of each RS getting a fixed number, which i will later use in the formula to calculate my %w/w of RS in my product -where i will have to calculate my standard in terms of base again (because my product's claim is expressed as base). Did i understand correcly? Does that mean that i do the conversion (Ranitidine HCl to base) twice or not?
Thank you for your time

Re: Correction Factors of related substances

Posted: Mon Aug 27, 2012 8:07 pm
by DR
You just do the conversion one time.

Calculate your ran.HCl concentration, then multuiply it by the ratio of
base formula weight / salt formula weight. This value is your standard concentration in the data system.

Re: Correction Factors of related substances

Posted: Mon Aug 27, 2012 9:24 pm
by Amalia
During the validation of RS i calculate the responce factor from the slope of Ranitidine HCl and the Relative Substance's slope. Do i make the conversion then at the concentration of Ranitidine HCl?
Thank you for your kind help!