<prompt> Local anaesthetic with maximum ionized form at physiological pHLignocaineEtidocaineBupivacaineChloroprocaine  <response>: Local anaesthetics with pKa value closest at physiological pH 7.4 will have a higher concentration of nonionized unionized base. Thus, the agent with pKa value away from physiological pH will have more concentration of ionized formChloroprocaine has highest pKa value, hence maximum ionized form at physiological pH.Refer: Morgan and Mikhails Clinical Anaesthesiology, 5th edition, pg no.268-270 