Please post this querry on Pharma PKBack to the Top
I have noticed one peculier problem, but not able to justify what can be
reason, hope one of you can throw some light.
We had one product "Erythromycin Ethyl Succinate 200 mg / 5ml in
form". The same was evaluated for dissolution profile as compared to
Innovator and both the refrence and test products showed more that 95%
dissolution in first 15 minutes in 0.1 N HCl, 0.01N HCl, 4.5 pH buffer.
checked in Ph6.8 both the products showed dissolution below 10% as drug
Dissolution profile in water is also same over the pH range of (5-6.8)
Assay of both these products in the range of +/- 5%
But when this product was evaluated for Bioequivalence, my product
higher bioequivalence as compared to Innovator viz AUC ratio more that
[Literature shows that, drug is readilly absorbed in GIT and Cmax of
hours and elimination half life of about 2 hours]
The point which I am mentioning here is when both these products shows
dissolution above 98% that meance they are in solution form in the
system and formulation is not a rate limiting step as pH range of 1.2 -
covers the portion of Stomach upto beganing of small instestine.
Then what can be reson for this mystery ?
Dear Dr. MaheshBack to the Top
I have few questions and probably answer to superequivalence may lie in
to these questions.
1. Have you done polymorphic studies of your raw material supplies, and
suspensions? what are the results?
2. are these dosage forms dry powder or ready use? In case of Dry
does user reconstitute the dry powder, using marking on bottle or
label or addition of predetermined exact measured quantity of water?
3. Have you checked for intrinsic solubility? why not do disso test
points of 5 and 10 minutes as well?
I hope these are the clues.
wishing you good luck
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