IBUPROFEN HETEROCYCLIC ESTERS AS DERMAL PRODRUGS IN-VITRO EVALUATION

Synthetic ibuprofen heterocyclic esters were assayed to determine thei r stability in water and isopropyl myristate, their susceptibility to enzymatic hydrolysis, and flux through excised rat skin. The biodegrad ability of the ester prodrugs was examined with porcine esterase in is otonic pH 7.4 phosphate buffer. The esters were readily hydrolysed in vitro by esterases and were stable in the given buffer, especially in isopropyl myristate. The skin permeation rate of ester compounds I to IV through the skin over 72 h was decreased compared to the parent dru g. The permeation rate at steady state (J(s)) of each compound was det ermined as follows : ibuprofen : 5.43, compound I : 2.05, compound II : 0.86, compound III : 0.51 and compound IV : 1.23 mu g/cm(2)/h, respe ctively.