The solubilization of some local anaesthetic ester of p-aminobenzoic acid by lysophosphatidylcholine.

The solubilization by lysophosphatidylcholine (LPC) of three n-alkyl esters of p-aminobenzoic acid has been studied. These esters have a local anaesthetic action. Quantitative studies show that the amount of compound solubilized is proportional to the LPC concentration and that solubilization increases in the order ethyl, n-propyl and n-butyl ester. 100MHz nmr studies indicate that the local anaesthetic esters are solubilized in the hydrocarbon interior of the LPC.