Efficient approach to acyloxymethyl esters of nalidixic acid and in vitro evaluation as intra-ocular prodrugs

Various alkylcarbonyloxymethyl esters of nalidixic acid ranging from 3 to 15 carbon units in the pro-moiety have been prepared and assessed as potential prodrugs. Their chromatographic retention factors k', silicone oil solubilities and in vitro conversion to nalidixic acid by a commercial esterase were determined together with their in vitro antimicrobial activity and cytotoxicity. The preliminary results suggest that silicone oil may have potential for the intra-ocular delivery of antibacterial compounds. Moreover, the in vitro release rate can be controlled by the lipophilicity of the prodrug.