Page 1 of 1
captopril tablets USP method
Posted: Fri Sep 02, 2005 4:17 am
by sneha
has anybody faced problem with analysis of captopril tablets using USP method
Posted: Fri Sep 02, 2005 5:46 pm
by Uwe Neue
Don't know the method, but if you are getting strange peak shapes with captopril you are probably at the wrong pH. Can you describe the method and the problem?
captopril tablets
Posted: Tue Sep 06, 2005 6:22 am
by sneha
the dissolution method invovles
media: 0.01nHcl, 900ml
basket:50rpm
detection by hplc
mobile phase: buffer: MEOH : 450: 550
buffer = (0.5ml OPA in 450ml WATER)
column :30cm c18 with 10microns
wavelength :220nm
USP suggest to inject samples immediately before 8hrs
i usually encountered problems like high Dissolution, and samples have to be injected within 2hrs.
secondaly assay with same chromatographic setup but diluent being diff
shows 100% assay if injected immediately and higher assay after even 1hr.
[/u]
could I ask you a question
Posted: Mon Sep 12, 2005 8:21 am
by ym3142
when you are talking about "USP suggest to inject samples immediately before 8hrs ; i usually encountered problems like high Dissolution, and samples have to be injected within 2hrs.
secondaly assay with same chromatographic setup but diluent being diff
shows 100% assay if injected immediately and higher assay after even 1hr. " are you meaing that the detected amount increases with the time of sample storage before injection such as 40% at 10:00 AM when the sample is prepared and injected, 45% at 11:00 AM if the same sample was injected again, and 50% at 12:00 AM if the same sample was injected again....?
If so, could you set up a way so you always inject the samples with the same delay or immediately? I am sorry to bother you.
Posted: Tue Sep 13, 2005 7:13 am
by syx
I think Captopril is unstable in aqueous media. You may store the sample in cooler, in vials those closed tightly to reduce degradation rate. Is it light sensitive too?