Pharmacokinetic and biodistribution study of eserine and pralidoxime chloride in rabbits following a single application of a transdermal patch.

In the present study, a simple reverse-phase high-performance liquid chromatography method with diode array detection has been developed and validated for the simultaneous determination and quantification of eserine and pralidoxime chloride in rabbit plasma and its application to pharmacokinetic study. The pharmacokinetic study was performed after transdermal application of single patch in rabbits. The plasma levels of both drugs following transdermal application of single patch were maintained for 72 h after removal of the patch. The maximal concentrations (C max) of both drugs were significantly reduced while the mean areas under the plasma concentration vs. time moment curve and mean residence times were evidently increased and extended, respectively. A sustained activity was observed over a period of 3 days. This sustained activity was due to the controlled release of drug into the systemic circulation following transdermal application. Linear correlation was also observed when fraction of drug permeated was correlated with the fraction of drug absorbed at the same time point. Gamma scintigraphy imaging on rabbit following transdermal patch application was performed to ascertain the localization of drugs in rabbit brain.