Use of over the counter oral relief aids or dietary supplements for the ring-opening polymerization of lactide

Over the counter oral relief aids or dietary supplements, namely calcium carbonate, calcium hydroxyapatite, magnesium oxide, zinc oxide, Tums (R) and Pepto-Bismol (R) have been investigated in the melt ringopening polymerization of lactide and a direct comparison with that involving tin(II) octanoate has been made. Of these, Pepto-Bismol (R) is shown to be the most active and comparable to tin octanoate. The active ingredient in Pepto-Bismol (R) is bismuth subsalicylate and when this is employed as the initiator similar results are obtained in melt polymerizations which suggests it could be employed as an alternative to the commercially used tin(II) octanoate.