Preservatives in pharmaceutical formulations

[angupa]

I would like to know if there is someone that is working with determination of preservatives in pharmaceuticals.
I want to develop an HPLC method to quantify methyl parahydroxybenzoate, propyl parahydroxybenzoate and sodium citrate in a parenteral formulation. Is there any bibilographic reference about this?

[Consumer Products Guy]

The first two (parabens) are readily assayed on RP-18 using water-ACN, maybe better if buffered at acidic pH, using UV detection at 280 nm. Citrates we done on ion exclusion column with sulfuric acid eluent and conductivity detector. Any HPLC column supplier should have applications for these, they are common.