Dear Sir. Concerning your issue about the method for propylene glycol alginate estimation. Two samples of propylene glycol alginate (PGA), one uniformly labelled with ~'*C in the alginate moiety and the other labelled with 14C in the propylene glycol moiety were administered to mice by gastric intubation. In the former case, 1 ml of a 10 ~ aqueous solution was given and in the latter, 0.5 ml of a 5% solution, providing in both cases a dose of 2 tzc. The absorption, distribution through the body tissues and excretion of label were followed from 1 hr to 5 days after administration, using the technique of whole-body autoradiography. Results were consistent with the proposition that the alginate moiety and any unhydrolysed ester are not absorbed from the gastro-intestinal tract but that, at the dosage level given, partial hydrolysis does occur, the propylene glycol being absorbed and metabolized by known pathways. A single dose of the compound was eliminated virtually completely within 5 days of administration to mice I think the following below links and the attached file may help you in your analysis: