Endotoxin content testing of injection

Dear all,

we have a product that is multivitamin having 2 to 3 Constituent in it in 1 ml vial. the specification provided mentions its endotoxin limit as 350EU/ml (using K/M calculation). we use gel clot assay. The MVD then comes to be about 2800 (using 0.125 lysate sensitivity) we consider potency/conc or product as 1 ml and we test 1:700 dilution.

However recently we faced certain complaints of this product. The sample tested had passed at MVD. Now we plan to perform quantitative testing by using different dilutions of the product.

can anyone quide how will i quantify the obtained endotoxin, for eg if dilution of 1:350 gives +ve gel clot what should i infer is the endotoxin content of my product.

thanking in anticipation.